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Oral-History:Chester Smith

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== About Chester Smith  ==
 
== About Chester Smith  ==
  
Dr. Chester Smith's career focused on the problem of electric interference. Smith was part of the early IEEE Electromagnetic Control Society (EMC), and has witnessed the evolution of interference control from World War One to the present. During World War Two, Smith served overseas with the U.S. Army Signal Corps, working on naval communications and interference problems. After the war, he helped develop national standards for controlling interference effects and helped eliminate interference in the Air Force's ground wave emergency network.  
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<p>Dr. Chester Smith's career focused on the problem of electric interference. Smith was part of the early IEEE Electromagnetic Compatibility Society (EMC), and has witnessed the evolution of interference control from World War One to the present. During World War Two, Smith served overseas with the U.S. Army Signal Corps, working on naval communications and interference problems. After the war, he helped develop national standards for controlling interference effects and helped eliminate interference in the Air Force's ground wave emergency network. </p>
  
The interview does not cover Smith's background or education, but instead begins rather suddenly with his descriptions of the EMC. Smith focuses on the history of interference control, particularly the work of the EMC and the American National Standards Institute. He credits amateur radio operators' contributions to the field, and gives examples of how frequency management and equipment tuning eliminate interference problems. Smith also discusses computer leakage, electromagnetic pulse effects, and electronic jamming. He recommends other people to interview, and closes with his reminiscences of World War Two and the first days of the Cold War.  
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<p>The interview does not cover Smith's background or education, but instead begins rather suddenly with his descriptions of the EMC. Smith focuses on the history of interference control, particularly the work of the EMC and the American National Standards Institute. He credits amateur radio operators' contributions to the field, and gives examples of how frequency management and equipment tuning eliminate interference problems. Smith also discusses computer leakage, electromagnetic pulse effects, and electronic jamming. He recommends other people to interview, and closes with his reminiscences of World War Two and the first days of the Cold War. </p>
 
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<br>  
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== About the Interview  ==
 
== About the Interview  ==
  
Chester Smith: An Interview Conducted by William Aspray, IEEE History Center, April 8, 1993  
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<p>Chester Smith: An Interview Conducted by William Aspray, IEEE History Center, April 8, 1993 </p>
  
Interview # 151 for the IEEE History Center, The Institute of Electrical and Electronics Engineers, Inc. and Rutgers, The State University of New Jersey
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<p>Interview # 151 for the IEEE History Center, The Institute of Electrical and Electronics Engineers, Inc. </p>
 
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<br>  
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== Copyright Statement  ==
 
== Copyright Statement  ==
  
This manuscript is being made available for research purposes only. All literary rights in the manuscript, including the right to publish, are reserved to the IEEE History Center. No part of the manuscript may be quoted for publication without the written permission of the Director of IEEE History Center.  
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<p>This manuscript is being made available for research purposes only. All literary rights in the manuscript, including the right to publish, are reserved to the IEEE History Center. No part of the manuscript may be quoted for publication without the written permission of the Director of IEEE History Center. </p>
  
Request for permission to quote for publication should be addressed to the IEEE History Center Oral History Program, Rutgers - the State University, 39 Union Street, New Brunswick, NJ 08901-8538 USA. It should include identification of the specific passages to be quoted, anticipated use of the passages, and identification of the user.  
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<p>Request for permission to quote for publication should be addressed to the IEEE History Center Oral History Program, 39 Union Street, New Brunswick, NJ 08901-8538 USA. It should include identification of the specific passages to be quoted, anticipated use of the passages, and identification of the user. </p>
  
It is recommended that this oral history be cited as follows:  
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<p>It is recommended that this oral history be cited as follows: </p>
  
Chester Smith, an oral history conducted in 1993 by William Aspray, IEEE History Center, Rutgers University, New Brunswick, NJ, USA.  
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<p>Chester Smith, an oral history conducted in 1993 by William Aspray, IEEE History Center, New Brunswick, NJ, USA. </p>
 
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<br>  
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== Interview  ==
 
== Interview  ==
  
Interviewee: Chester Smith <br>Interviewer: William Aspray <br>Date: April 8, 1993 <br>Place:
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<p>Interviewee: Chester Smith </p>
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<p>Interviewer: William Aspray </p>
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<p>Place Unknown </p>
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<p>Date: April 8, 1993 </p>
  
 
=== Electromagnetic Control Society  ===
 
=== Electromagnetic Control Society  ===
  
'''Smith:'''  
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<p>'''Smith:''' </p>
  
The EMC Society started as the radio frequency interference group of IRE. The guiding light in those days was Rexford Daniels, who lived over here in Concord, Massachusetts, and he passed on three or four years ago. A couple of other people who are still around are Gene Knowles in Renton, Washington and Leonard Thomas. Len lives in Baltimore, Maryland. I would have to look up his address for you. Both of these people were in on the earliest days of the EMC society and I got involved in it a little bit later.  
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<p>The EMC Society started as the radio frequency interference group of IRE. The guiding light in those days was Rexford Daniels, who lived over here in Concord, Massachusetts, and he passed on three or four years ago. A couple of other people who are still around are Gene Knowles in Renton, Washington and [[Oral-History:Leonard Thomas Sr.|Leonard Thomas]]. Len lives in Baltimore, Maryland. I would have to look up his address for you. Both of these people were in on the earliest days of the EMC society and I got involved in it a little bit later. </p>
  
There was also someone by the name of Robert Berkovits, who now (1993) works with Grumman on Long Island, NY. Bob is one of those people who just never gives up. He kept the local chapter of the radio frequency interference group going, and when the IRE and the AIEE merged it became the electromagnetic compatibility group. I was the first chairman of the new merged chapter of Aerospace Electronic Systems (AES). To keep the Boston IEEE section from putting it out of business because they didn’t have enough meetings in a year, Bob used to bug me for joint meetings with AES. So we were holding joint meetings after the merger, and all during the 1960s. I moved into the EMC technology area, myself. The major concern then was effects of electromagnetic pulse and other nuclear phenomena on electronics. There were comments about some of the earlier studies in those newsletters that I sent you. You can find some of Rex Daniels’ original comments about it. Later there were some of the pioneering studies on cable coupling by Clayton Paul, a professor down at the University of Kentucky. He did a lot of early work on that and he is still very active.  
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<p>There was also someone by the name of Robert Berkovits, who now (1993) works with Grumman on Long Island, NY. Bob is one of those people who just never gives up. He kept the local chapter of the radio frequency interference group going, and when [[Formation of IEEE by the Merger of AIEE and IRE|the IRE and the AIEE merged]] it became the electromagnetic compatibility group. I was the first chairman of the new merged chapter of Aerospace Electronic Systems (AES). To keep the [[IEEE Boston Section History|Boston IEEE section]] from putting it out of business because they didn’t have enough meetings in a year, Bob used to bug me for joint meetings with AES. So we were holding joint meetings after the merger, and all during the 1960s. I moved into the EMC technology area, myself. The major concern then was effects of electromagnetic pulse and other nuclear phenomena on electronics. There were comments about some of the earlier studies in those newsletters that I sent you. You can find some of Rex Daniels’ original comments about it. Later there were some of the pioneering studies on cable coupling by Clayton Paul, a professor down at the University of Kentucky. He did a lot of early work on that and he is still very active. </p>
  
'''Aspray:'''  
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<p>'''Aspray:''' </p>
  
What’s the issue there?  
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<p>What’s the issue there? </p>
  
'''Smith:'''  
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<p>'''Smith:''' </p>
  
Wire coupling. I think it really got started as an outgrowth of studies by the telephone people because they were very interested in keeping their circuits free of cross-talk. So there was some early work done on that, but I don’t think they ever took it to the degree that Dr. Paul has with his studies. Who else would be a major pioneer?  
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<p>Wire coupling. I think it really got started as an outgrowth of studies by the telephone people because they were very interested in keeping their circuits free of cross-talk. So there was some early work done on that, but I don’t think they ever took it to the degree that Dr. Paul has with his studies. Who else would be a major pioneer? </p>
  
On Fields, Myron Crawford at the Bureau of Standards is another person that you ought to talk to. The famous Crawford Cell is named after him. It is a TEM mode device for studying effects of fields on devices. Put your electronic widget in there and zap it! The field can be adjusted spacing from a low to high impedance type field or of course, it can be set to a straight transverse electromagnetic field (377Ω). That is another major area that needs attention. Another area when you talk about the history of electromagnetics interference control is frequency management. Now EMC-S has a whole task group and it has been active for many years. I was involved with that group for a while in the mid-1970s. One way among others to control electromagnetic interference is to control the way the spectrum is managed. We dealt with such things as cross-polarization effects, time-sharing, and this whole list.  
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<p>On Fields, Myron Crawford at the Bureau of Standards is another person that you ought to talk to. The famous Crawford Cell is named after him. It is a TEM mode device for studying effects of fields on devices. Put your electronic widget in there and zap it! The field can be adjusted spacing from a low to high impedance type field or of course, it can be set to a straight transverse electromagnetic field (377Ω). That is another major area that needs attention. Another area when you talk about the history of electromagnetics interference control is frequency management. Now EMC-S has a whole task group and it has been active for many years. I was involved with that group for a while in the mid-1970s. One way among others to control electromagnetic interference is to control the way the spectrum is managed. We dealt with such things as cross-polarization effects, time-sharing, and this whole list. </p>
  
 
=== Military Impetus for EMC Research  ===
 
=== Military Impetus for EMC Research  ===
  
'''Aspray:'''  
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<p>'''Aspray:''' </p>
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<p>How did the Society come about in the first place? Where were most of the people drawn from? </p>
  
How did the Society come about in the first place? Where were most of the people drawn from?
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<p>'''Smith:''' </p>
  
'''Smith:'''
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<p><flashmp3>Image:151 - smith - clip 1.mp3</flashmp3> </p>
  
The big push really for the creation of the Society in the first place came from two major military sources: the Air Force and the Navy. The problem being that the equipment of these services can be pretty cramped as far as space which is conducive of cross-coupling. The other military people, the Army and the Marines, didn’t seem to be too perturbed about it. They spread out more. The civilian market is just now beginning to really wake up and we are getting quite a bit of static out of the European people. But the major push for it came from the military. You have to get Len Thomas’s version of it. He tells the story about making some design measurements with a field strength meter and antennas in a field near the Navy boot training station in San Diego. They were out measuring and taking readings on the fields. A Navy captain, a four-striper, came out there and wanted to know what they were doing. He said, “We are making field strength measurements.” The captain looked at him kind of funny and then stomped on the ground a few times, and he said, “This field looks strong enough to me.”  
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<p>The big push really for the creation of the Society in the first place came from two major military sources: the Air Force and the Navy. The problem being that the equipment of these services can be pretty cramped as far as space which is conducive of cross-coupling. The other military people, the Army and the Marines, didn’t seem to be too perturbed about it. They spread out more. The civilian market is just now beginning to really wake up and we are getting quite a bit of static out of the European people. But the major push for it came from the military. You have to get Len Thomas’s version of it. He tells the story about making some design measurements with a field strength meter and antennas in a field near the Navy boot training station in San Diego. They were out measuring and taking readings on the fields. A Navy captain, a four-striper, came out there and wanted to know what they were doing. He said, “We are making field strength measurements.” The captain looked at him kind of funny and then stomped on the ground a few times, and he said, “This field looks strong enough to me.” </p>
  
Interference on board ship was a major driver because they were stacking electronic boxes and antennas were right next to each other, all near field coupling, and the thing would get to be a hairy mess. The Air Force was not far behind them. Both services, particularly the Air Force, became very interested in the electromagnetic pulse effects. That is because they would presumably have to fly near where something like that might happen. That is another major area where an important function created a lot of interest.  
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<p>Interference on board ship was a major driver because they were stacking electronic boxes and antennas were right next to each other, all near field coupling, and the thing would get to be a hairy mess. The Air Force was not far behind them. Both services, particularly the Air Force, became very interested in the electromagnetic pulse effects. That is because they would presumably have to fly near where something like that might happen. That is another major area where an important function created a lot of interest. </p>
  
Civilian markets have really taken off recently over the last five or six years. I have spent some time on American National Standards Institute’s C63 Committee. Germany is probably the tightest about interference effects. The Federal Communications Commission has had authorization in the Goldwater-Vanick-Wirth Bill of 1982 to write immunity standards, but the bill did not mandate it. So all the Federal Communications Commission’s rules and regulations on it deal only with emissions. However, ANSI, IEEE and jointly C63 sub-committee 5 chaired by Don Heirman of AT&amp;T labs in Holmdel, are working on the immunity standard. The FCC participates in it, chiefly in the person of Arthur Wall. Also they have taken some steps to answer people who are complaining about interference effects, but mainly they (the FCC) pushed it off on the manufacturers. If one complains loudly enough maybe they (the manufacturer) will do something. Most of the people don’t worry about it or just live with it. I read a paper a year ago at a meeting in Denver on the domestic EMC standard. It dealt with some rather innocuous things like those little colorful sprinkles you see on your television set when somebody turns on a hair dryer or a mixer or something. Those are just annoying, but it is not so funny when it gets into the navigation equipment of an airliner.  
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<p>Civilian markets have really taken off recently over the last five or six years. I have spent some time on American National Standards Institute’s C63 Committee. Germany is probably the tightest about interference effects. The Federal Communications Commission has had authorization in the Goldwater-Vanick-Wirth Bill of 1982 to write immunity standards, but the bill did not mandate it. So all the Federal Communications Commission’s rules and regulations on it deal only with emissions. However, ANSI, IEEE and jointly C63 sub-committee 5 chaired by Don Heirman of AT&amp;T labs in Holmdel, are working on the immunity standard. The FCC participates in it, chiefly in the person of Arthur Wall. Also they have taken some steps to answer people who are complaining about interference effects, but mainly they (the FCC) pushed it off on the manufacturers. If one complains loudly enough maybe they (the manufacturer) will do something. Most of the people don’t worry about it or just live with it. I read a paper a year ago at a meeting in Denver on the domestic EMC standard. It dealt with some rather innocuous things like those little colorful sprinkles you see on your television set when somebody turns on a hair dryer or a mixer or something. Those are just annoying, but it is not so funny when it gets into the navigation equipment of an airliner. </p>
  
'''Aspray:'''  
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<p>'''Aspray:''' </p>
  
I could imagine.  
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<p>I could imagine. </p>
  
'''Smith:'''  
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<p>'''Smith:''' </p>
  
We found that with the low frequencies (a few KHz to MHz) primarily conducted, we weren’t seeing too much in the way of radiation. But when the frequency was up to the high end of HF and into VHF, it was by antenna-like structure, such as lead-ins and power cords almost entirely radiated and then picked up. It is also common mode.  
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<p>We found that with the low frequencies (a few KHz to MHz) primarily conducted, we weren’t seeing too much in the way of radiation. But when the frequency was up to the high end of HF and into VHF, it was by antenna-like structure, such as lead-ins and power cords almost entirely radiated and then picked up. It is also common mode. </p>
  
'''Aspray:'''  
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<p>'''Aspray:''' </p>
  
What other companies or government organizations that were interested in these kinds of problems made studies of them?  
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<p>What other companies or government organizations that were interested in these kinds of problems made studies of them? </p>
  
'''Smith:'''  
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<p>'''Smith:''' </p>
  
The Army got very interested in the mid-1960s in the effect of electromagnetic pulses on their fielded equipment. There has always of course been the business of the outgrowth of the radar and electronic warfare area. Would your equipment stand up against a radar set? So they played a lot of games with that. Some of that stuff is still pretty highly classified.  
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<p>The Army got very interested in the mid-1960s in the effect of electromagnetic pulses on their fielded equipment. There has always of course been the business of the outgrowth of the radar and electronic warfare area. Would your equipment stand up against a radar set? So they played a lot of games with that. Some of that stuff is still pretty highly classified. </p>
  
'''Aspray:'''  
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<p>'''Aspray:''' </p>
  
Do you know where it was done? What locations in the Army?  
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<p>Do you know where it was done? What locations in the Army? </p>
  
'''Smith:'''  
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<p>'''Smith:''' </p>
  
Some of it was done here at MIT. Most of the major universities had a finger in the pie at one time or another. Ohio State did an awful lot of work. They were looking at the antenna-to-antenna kind of coupling. How to couple, how to decouple, generally how to handle nuclear interference problems. Syracuse University was big in it too; they were involved with the IEMCAP program. The IEMCAP is Interference and Electromagnetic Control Analysis Program. It came out of Rome [NY] Development Center at the Griffiss Air Base. The initial work was done by McDonnell-Douglas in St. Louis, and the program was extremely bulky and very awkward to use when Rome Development Center asked for the models for antenna-to-antenna coupling and things like that. The company took an attitude that the models were proprietary. People at RADC gave a reverse engineering contract to Don Wiener and his outfit at Syracuse to go back over the thing. For example it didn’t handle switching well. It used a power series for the electronic and analytical modeling. By the time you got enough turns to make this square wave a good amount of computer time had been burned up. I was talking to Al Leber who was sort of the grandfather of this whole thing, he is a Rand guy from the West Coast. He is the one who put RADC up to doing this in the first place. I guess it was that extra Manhattan that did it. I told him that the antenna coupling model was wrong. What they did was put the antenna on top of the airplane and another one on the bottom. If you tied a string for the shortest possible path, that’s what they used. Then they treated it as if it were a free space, Friis-type coupling, as if these antennas were in free space looking at each other. Well, that sounds like a worst-case example, and unfortunately it is not. There are corners in airplane structure, in the tails and other places. The shortest path may not represent the tightest coupling. They followed that up with a contract to Bill Duff at Atlantic Research. His group rewrote that part of the IEMCAP code to couple by the tightest path, not necessarily by the shortest. I felt pretty good about that one. That was the major effort that went into it. That was a big program and it is still around. Kaman Sciences in Utica has copies of that program now so that any government contracting company or educational institution can get a copy of it. They also have it revised to run on a PC.  
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<p>Some of it was done here at MIT. Most of the major universities had a finger in the pie at one time or another. Ohio State did an awful lot of work. They were looking at the antenna-to-antenna kind of coupling. How to couple, how to decouple, generally how to handle nuclear interference problems. Syracuse University was big in it too; they were involved with the IEMCAP program. The IEMCAP is Interference and Electromagnetic Control Analysis Program. It came out of Rome [NY] Development Center at the Griffiss Air Base. The initial work was done by McDonnell-Douglas in St. Louis, and the program was extremely bulky and very awkward to use when Rome Development Center asked for the models for antenna-to-antenna coupling and things like that. The company took an attitude that the models were proprietary. People at RADC gave a reverse engineering contract to Don Wiener and his outfit at Syracuse to go back over the thing. For example it didn’t handle switching well. It used a power series for the electronic and analytical modeling. By the time you got enough turns to make this square wave a good amount of computer time had been burned up. I was talking to Al Leber who was sort of the grandfather of this whole thing, he is a Rand guy from the West Coast. He is the one who put RADC up to doing this in the first place. I guess it was that extra Manhattan that did it. I told him that the antenna coupling model was wrong. What they did was put the antenna on top of the airplane and another one on the bottom. If you tied a string for the shortest possible path, that’s what they used. Then they treated it as if it were a free space, [[Harald T. Friis|Friis]]-type coupling, as if these antennas were in free space looking at each other. Well, that sounds like a worst-case example, and unfortunately it is not. There are corners in airplane structure, in the tails and other places. The shortest path may not represent the tightest coupling. They followed that up with a contract to Bill Duff at Atlantic Research. His group rewrote that part of the IEMCAP code to couple by the tightest path, not necessarily by the shortest. I felt pretty good about that one. That was the major effort that went into it. That was a big program and it is still around. Kaman Sciences in Utica has copies of that program now so that any government contracting company or educational institution can get a copy of it. They also have it revised to run on a PC. </p>
  
Also, a version of it has been re-worked by Lawrence Livermore Labs, and that’s available from the Naval Post-Graduate Center in Monterey, CA. They have format now so instead of computer paper stacked four feet high, the output comes out on a single 8 1/2 x 11 inch sheet. You list all the electronic goodies down one side and across the top, and it sorts itself. Any interference within ten dB of that a pre-set threshold marks. It can think a candidate list of ten thousand or a hundred thousand possible interferences down to maybe less than one hundred. It is not a very smart program in the sense that it has a tendency to yell wolf when there is no wolf. In closer analysis of the areas where it says to look, most of them will go away and end up with at least five or ten. Those are the areas that require redesign. So that’s about what I know about that. I have used the program. The biggest problem with it is that it costs quite a bit to get the baseline in. Once the baseline is set, it’s not much trouble to modify it, to try changes, to move things around. It takes a big machine; an IBM 370 or something of that sort would run it. Jerry Caprero (sic) at Kaman Sciences says he has a cut-down version that would run on a good-sized PC; a 386 or 486 can handle it quite happily, but it is slow compared to big frames. They left out some things that don’t trouble most people. In the original program they had some routine that calculated the electrical disturbances when a satellite crosses the magnetopause, but most of us don’t need that. It is not something we see in the average airplane or ground vehicle.  
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<p>Also, a version of it has been re-worked by Lawrence Livermore Labs, and that’s available from the Naval Post-Graduate Center in Monterey, CA. They have format now so instead of computer paper stacked four feet high, the output comes out on a single 8 1/2 x 11 inch sheet. You list all the electronic goodies down one side and across the top, and it sorts itself. Any interference within ten dB of that a pre-set threshold marks. It can think a candidate list of ten thousand or a hundred thousand possible interferences down to maybe less than one hundred. It is not a very smart program in the sense that it has a tendency to yell wolf when there is no wolf. In closer analysis of the areas where it says to look, most of them will go away and end up with at least five or ten. Those are the areas that require redesign. So that’s about what I know about that. I have used the program. The biggest problem with it is that it costs quite a bit to get the baseline in. Once the baseline is set, it’s not much trouble to modify it, to try changes, to move things around. It takes a big machine; an IBM 370 or something of that sort would run it. Jerry Caprero (sic) at Kaman Sciences says he has a cut-down version that would run on a good-sized PC; a 386 or 486 can handle it quite happily, but it is slow compared to big frames. They left out some things that don’t trouble most people. In the original program they had some routine that calculated the electrical disturbances when a satellite crosses the magnetopause, but most of us don’t need that. It is not something we see in the average airplane or ground vehicle. </p>
  
 
=== Civilian Concerns with EMC  ===
 
=== Civilian Concerns with EMC  ===
  
'''Smith:'''  
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<p>'''Smith:''' </p>
  
The civilian side of EMC will be a biggie from now on I think, for two reasons: first, the military is beginning to wake up with the fact that they won’t be inspecting everything since they found that that costs too much. I don’t know the relative changes and costs. It’s like half again or twice as much for the absolutely the same identical item. I remember pricing some transmitters. One was for an over-the-counter item at most radio retail stores, Radio Shack for example. It cost at that time about $250 to buy it over-the-counter. The military price was about $400. The company said that they had to do that because the government asked for a long list of tests and checks. Consequently they couldn’t afford to sell it to the government at the lower price. The FCC is tightening up the electromagnetic requirements on civilian items. Now immunity standards are being prepared by ANSI. These are being coordinated with the European ones. CISPR’s [International Special Committee on Radio Interference] set of standards are strictly advisory. Even though they are advisory, manufacturers ignore them at their peril. Fortunately, a number of countries have adopted them as law. Belgium and Spain for example bought CISPR regulations and they are now the law of the land. The Germans and the British have always had their own. The German rules are pretty stiff. The penalty for trying to take a piece of electronic equipment into Germany that does not meet their requirements is not only a big fine, but the government may confiscate your shipment and destroy it. So this has strongly motivated people to meet the rules.  
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<p>The civilian side of EMC will be a biggie from now on I think, for two reasons: first, the military is beginning to wake up with the fact that they won’t be inspecting everything since they found that that costs too much. I don’t know the relative changes and costs. It’s like half again or twice as much for the absolutely the same identical item. I remember pricing some transmitters. One was for an over-the-counter item at most radio retail stores, Radio Shack for example. It cost at that time about $250 to buy it over-the-counter. The military price was about $400. The company said that they had to do that because the government asked for a long list of tests and checks. Consequently they couldn’t afford to sell it to the government at the lower price. The FCC is tightening up the electromagnetic requirements on civilian items. Now immunity standards are being prepared by ANSI. These are being coordinated with the European ones. CISPR’s [International Special Committee on Radio Interference] set of standards are strictly advisory. Even though they are advisory, manufacturers ignore them at their peril. Fortunately, a number of countries have adopted them as law. Belgium and Spain for example bought CISPR regulations and they are now the law of the land. The Germans and the British have always had their own. The German rules are pretty stiff. The penalty for trying to take a piece of electronic equipment into Germany that does not meet their requirements is not only a big fine, but the government may confiscate your shipment and destroy it. So this has strongly motivated people to meet the rules. </p>
  
The latest goings-on in the EMC field... Well, IEEE isn’t the only outfit that’s been involved in the Society of Automotive Engineers. The so-called SAE-4 Committee has been dealing with interference ever since people started putting Motorola radios in cars. At first ignition noise all but made the radios useless if the transmitters were not nearby. The remedy was to use carbon filament high-tension wires to go to the spark plugs. Replacing the wire with a filament of carbon cut down most of the noise without interfering with the spark action. Now that there are a lot of other electronic goodies going into cars, two-way radio, cellular radio...  
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<p>The latest goings-on in the EMC field... Well, IEEE isn’t the only outfit that’s been involved in the Society of Automotive Engineers. The so-called SAE-4 Committee has been dealing with interference ever since people started putting Motorola radios in cars. At first ignition noise all but made the radios useless if the transmitters were not nearby. The remedy was to use carbon filament high-tension wires to go to the spark plugs. Replacing the wire with a filament of carbon cut down most of the noise without interfering with the spark action. Now that there are a lot of other electronic goodies going into cars, two-way radio, cellular radio... </p>
  
'''Aspray:'''  
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<p>'''Aspray:''' </p>
  
Cellular phones, right.  
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<p>Cellular phones, right. </p>
  
 
=== Hazards of Electromagnetic Fields  ===
 
=== Hazards of Electromagnetic Fields  ===
  
'''Smith:'''  
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<p>'''Smith:''' </p>
  
You have phones and that sort of thing. The other major area that you should consider that has really boiled over now is personnel hazards with electromagnetic fields. That famous Denver study by that woman doctor, I think was so badly controlled that it is next to worthless.  
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<p>You have phones and that sort of thing. The other major area that you should consider that has really boiled over now is personnel hazards with electromagnetic fields. That famous Denver study by that woman doctor, I think was so badly controlled that it is next to worthless. </p>
  
'''Aspray:'''  
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<p>'''Aspray:''' </p>
  
Have there been studies by your society?  
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<p>Have there been studies by your society? </p>
  
'''Smith:'''  
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<p>'''Smith:''' </p>
  
Yes, they are working on it. Almost every year at the symposium there will be two or three papers on it and sometimes they will hold sessions on five or six of them. There is a lot of overlap: the SAE 4, the ANSI, etc., have the same cast of characters. A lot of people on one committee are on another or they are working in the field and they know each other; it is a big club. Sometimes we meet in Washington and the next time somewhere else. It is almost a floating crap game: we are in Dallas, San Diego or something, but it is the same bunch of people. Herb Mertel is involved with international standards and I was looking at domestic EMC problems, antennas. The antenna people, standardizing test facilities it is the same group of people who float around. At one time they are the IEEE group, and the same bunch later meet as ANSI-C63. This tends to confuse everybody, but it is a lot of the same people. Bob Hoffman, for example, I know for a fact is on at least three of those committees. Don Heirman I know is nearly on every one of them.  
+
<p>Yes, they are working on it. Almost every year at the symposium there will be two or three papers on it and sometimes they will hold sessions on five or six of them. There is a lot of overlap: the SAE 4, the ANSI, etc., have the same cast of characters. A lot of people on one committee are on another or they are working in the field and they know each other; it is a big club. Sometimes we meet in Washington and the next time somewhere else. It is almost a floating crap game: we are in Dallas, San Diego or something, but it is the same bunch of people. Herb Mertel is involved with international standards and I was looking at domestic EMC problems, antennas. The antenna people, standardizing test facilities it is the same group of people who float around. At one time they are the [[IEEE History|IEEE]] group, and the same bunch later meet as ANSI-C63. This tends to confuse everybody, but it is a lot of the same people. Bob Hoffman, for example, I know for a fact is on at least three of those committees. Don Heirman I know is nearly on every one of them. </p>
  
'''Aspray:'''  
+
<p>'''Aspray:''' </p>
  
Do you think that is good or bad?  
+
<p>Do you think that is good or bad? </p>
  
'''Smith:'''  
+
<p>'''Smith:''' </p>
  
The good side to it is this: different parent organizations see the commonalty of the problems. That’s the good side. The bad side is that the thing is incestuous; the same people do all the same stuff.  
+
<p>The good side to it is this: different parent organizations see the commonalty of the problems. That’s the good side. The bad side is that the thing is incestuous; the same people do all the same stuff. </p>
  
 
=== American Radio Relay League  ===
 
=== American Radio Relay League  ===
  
'''Aspray:'''  
+
<p>'''Aspray:''' </p>
  
If you were to look way back in history, where were the first interference problems addressed?  
+
<p>If you were to look way back in history, where were the first interference problems addressed? </p>
  
'''Smith:'''  
+
<p>'''Smith:''' </p>
  
The American Radio Relay League was talking about that in 1927.  
+
<p>The American Radio Relay League was talking about that in 1927. </p>
  
'''Aspray:'''  
+
<p>'''Aspray:''' </p>
  
What was the context?  
+
<p>What was the context? </p>
  
'''Smith:'''  
+
<p>'''Smith:''' </p>
  
The amateurs and the professionals were interfering, or the professionals were interfering with the hams and the hams vice-versa. This was the day when the vacuum tube was just beginning to get common. A lot of the rigs in those days were spark gap. One of the favorite rigs of the hams was the Ford Model T ignition coil. You know where the American Radio Relay League is headquartered. They are in Newington, Connecticut, at 225 Main Street. The executive vice-president is a man by the name of David Sumner. He is very personable and a very easy guy to talk to.  
+
<p>The amateurs and the professionals were interfering, or the professionals were interfering with the hams and the hams vice-versa. This was the day when the vacuum tube was just beginning to get common. A lot of the rigs in those days were spark gap. One of the favorite rigs of the hams was the Ford Model T ignition coil. You know where the American Radio Relay League is headquartered. They are in Newington, Connecticut, at 225 Main Street. The executive vice-president is a man by the name of David Sumner. He is very personable and a very easy guy to talk to. </p>
  
Some of the earliest papers that I have run across dealing with interference... 1927 through 1957, was thirty years before the pros began to really wake up. Then Rexford Daniels and some others began to wake up the professionals. The amateur fraternity had dealt with it. They are not a bunch of lightweights; you have a lot of Ph.D.’s among the radio amateurs. They have produced a lot of papers of the quality that one would really expect of a professional writer. To my personal knowledge the earliest paper dealing specifically and exclusively with radio interference was that 1927 paper in ''QST'', their magazine. This goes back to Marconi himself; I think he and Herz must have had a problem. It goes way, way back.  
+
<p>Some of the earliest papers that I have run across dealing with interference... 1927 through 1957, was thirty years before the pros began to really wake up. Then Rexford Daniels and some others began to wake up the professionals. The amateur fraternity had dealt with it. They are not a bunch of lightweights; you have a lot of Ph.D.’s among the radio amateurs. They have produced a lot of papers of the quality that one would really expect of a professional writer. To my personal knowledge the earliest paper dealing specifically and exclusively with radio interference was that 1927 paper in ''QST'', their magazine. This goes back to Marconi himself; I think he and Herz must have had a problem. It goes way, way back. </p>
  
 
=== Government Regulation  ===
 
=== Government Regulation  ===
  
'''Aspray:'''  
+
<p>'''Aspray:''' </p>
  
Did the government take a hand in this by regulation?  
+
<p>Did the government take a hand in this by regulation? </p>
  
'''Smith:'''  
+
<p>'''Smith:''' </p>
  
Not right away. The regulations came later when the Hoover Commission set them up before Herbert Hoover was elected President. Mostly the pros were interfering with each other. Of course, public broadcasting was being promoted: KDKA was on the air, but not many other stations. The news people were getting information back and forth inter-continentally with very low frequency (VLF 30 - 300kHz), and they were using these huge antennas. The Beverage antenna for receiving and transmitting was not a very efficient device, but it is quite directional. They were communicating with Morse code, hence the NCW, and they had operators. That was also the same time when the secrecy provision in the international treaty was implemented. Of course, in following up on the ''Titanic'' problem, there was an international treaty that required the ships to carry radio. The generators, the electric lights, and so forth were big open-coil things with lots of sparks. I am sure if we burrowed around we could find some comments about interference in the early days.  
+
<p>Not right away. The regulations came later when the Hoover Commission set them up before Herbert Hoover was elected President. Mostly the pros were interfering with each other. Of course, public broadcasting was being promoted: KDKA was on the air, but not many other stations. The news people were getting information back and forth inter-continentally with very low frequency (VLF 30 - 300kHz), and they were using these huge antennas. The Beverage antenna for receiving and transmitting was not a very efficient device, but it is quite directional. They were communicating with Morse code, hence the NCW, and they had operators. That was also the same time when the secrecy provision in the international treaty was implemented. Of course, in following up on the ''Titanic'' problem, there was an international treaty that required the ships to carry radio. The [[Generators|generators]], the electric lights, and so forth were big open-coil things with lots of sparks. I am sure if we burrowed around we could find some comments about interference in the early days. </p>
  
Basically Hoover’s commission set up the bands. The low frequency bands, the MF broadcast band that ran from 550 to 1500 kHz. The amateurs were relegated to 200 meters, shorter wavelengths. When they started screwing around we found out that frequencies around fourteen to fifteen megahertz were going all over the world with only a few watts. Commercials began a rush in there and amateurs were restricted to set bands that were originally harmonic. The idea behind the harmonic was an interference problem; if someone on 160-meters (1700-2000 kHz) had a harmonic, it would land on the 80 meter band. From forty to twenty to ten, and then ten to five and finally two and a half meters; anything above that was fair game. That condition lasted until World War II broke out, but the idea behind it was that ham interference problem would only trouble with their own people. The American Radio Relay League’s magazine and a couple of other clubs began to publish articles on harmonic suppression and generally began to look into the technology of narrowing signal bandwidth. They were advocating crystal control and doing some interesting research on filters. The early filters were bulky things. They were made with wires, homemade coils and so on, but the things worked. One could put those things between the transmitter and the antenna and they pretty well cleaned up the signal. A lot of their 1930s articles on how to build circuits dealt with the issue of suppressing parasitic oscillations, which is a source of unwanted radiation. The amateur fraternity was about thirty years ahead of the pros when it came to formal recognition of the seriousness of interference and the technology for controlling it. Give them brownie points. Some of these guys were professors at MIT and other universities, like John Kraus, Professor Emeritus now at Ohio State. These people wrote a lot of the articles, so I am saying that they weren’t all backyard experimenters and high school kids just playing with flukes. They were pretty serious people.  
+
<p>Basically Hoover’s commission set up the bands. The low frequency bands, the MF broadcast band that ran from 550 to 1500 kHz. The amateurs were relegated to 200 meters, shorter wavelengths. When they started screwing around we found out that frequencies around fourteen to fifteen megahertz were going all over the world with only a few watts. Commercials began a rush in there and amateurs were restricted to set bands that were originally harmonic. The idea behind the harmonic was an interference problem; if someone on 160-meters (1700-2000 kHz) had a harmonic, it would land on the 80 meter band. From forty to twenty to ten, and then ten to five and finally two and a half meters; anything above that was fair game. That condition lasted until World War II broke out, but the idea behind it was that ham interference problem would only trouble with their own people. The American Radio Relay League’s magazine and a couple of other clubs began to publish articles on harmonic suppression and generally began to look into the technology of narrowing signal bandwidth. They were advocating crystal control and doing some interesting research on filters. The early filters were bulky things. They were made with wires, homemade coils and so on, but the things worked. One could put those things between the transmitter and the antenna and they pretty well cleaned up the signal. A lot of their 1930s articles on how to build circuits dealt with the issue of suppressing parasitic oscillations, which is a source of unwanted radiation. The amateur fraternity was about thirty years ahead of the pros when it came to formal recognition of the seriousness of interference and the technology for controlling it. Give them brownie points. Some of these guys were professors at MIT and other universities, like [[John D. Kraus|John Kraus]], Professor Emeritus now at Ohio State. These people wrote a lot of the articles, so I am saying that they weren’t all backyard experimenters and high school kids just playing with flukes. They were pretty serious people. </p>
  
 
=== Magnetic Fields and Telephone Lines  ===
 
=== Magnetic Fields and Telephone Lines  ===
  
'''Aspray:'''  
+
<p>'''Aspray:''' </p>
  
Were the telephone engineers interested in these issues early on?  
+
<p>Were the telephone engineers interested in these issues early on? </p>
  
'''Smith:'''  
+
<p>'''Smith:''' </p>
  
Yes, they were but they were keeping to themselves. If you go through the Bell System journal you can find that occasionally they talked about it. They were concerned with circuit cross talk and then they started this base band and then the harmonic band to get more lines on the same circuit.  
+
<p>Yes, they were but they were keeping to themselves. If you go through the Bell System journal you can find that occasionally they talked about it. They were concerned with circuit cross talk and then they started this base band and then the harmonic band to get more lines on the same circuit. </p>
  
'''Aspray:'''  
+
<p>'''Aspray:''' </p>
  
I guess it was sometime in the 1930s there was a big lawsuit between the telephone companies and I think it was the utilities... I don’t remember if it was regular power transmission or railroad power that was interfering with telephone lines.  
+
<p>I guess it was sometime in the 1930s there was a big lawsuit between the telephone companies and I think it was the utilities... I don’t remember if it was regular power transmission or railroad power that was interfering with telephone lines. </p>
  
'''Smith:'''  
+
<p>'''Smith:''' </p>
  
All of them. Part of the problem was that their right-of-ways were limited. The municipalities controlled where they could put their lines. If the telephone company had its way of course, they would have been miles away, but the utilities, the municipalities and the county governments said, “You can run your pole line there, and the power company is running down there.” They were often times forced by government action to use the same poles. So then they started playing games about inverting every little bit; they twisted and rolled these things over to reduce the amount of coupling between them. The local quasi-static field around a power line is quite strong, and it may astonish you what the volts per meter under one of these lines is like. We have one going through Burlington into Lexington to a sub-station. It’s 365,000 volts phase to phase. That thing would put about 25,000 volts per meter where the cars run under it. No one stays in it very long, not at sixty-five miles per hour. It also has a pretty respectable magnetic field, but these are really non-propagating in that they don’t radiate. There is very slight radiation from things like that because the radiation resistance is of the order of micro-ohms. Wires are about ten meters apart, ten meters to a wavelength for sixty hertz (5000 km). From Boulder Dam to Los Angeles is about a quarter wavelength of that frequency, so figure it out from there. The moment is very small, so they don’t really radiate much, but the local field can be really juicy. I don’t recommend spending a great deal of time under it, but running under it with a car, which is basically a Faraday cage, won’t hurt anything. With running a telephone line in that dense fifty- or sixty-hertz field, of course it would hum like a bunch of bees, so they did play games to twist and try to help that.  
+
<p>All of them. Part of the problem was that their right-of-ways were limited. The municipalities controlled where they could put their lines. If the telephone company had its way of course, they would have been miles away, but the utilities, the municipalities and the county governments said, “You can run your pole line there, and the power company is running down there.” They were often times forced by government action to use the same poles. So then they started playing games about inverting every little bit; they twisted and rolled these things over to reduce the amount of coupling between them. The local quasi-static field around a power line is quite strong, and it may astonish you what the volts per meter under one of these lines is like. We have one going through Burlington into Lexington to a sub-station. It’s 365,000 volts phase to phase. That thing would put about 25,000 volts per meter where the cars run under it. No one stays in it very long, not at sixty-five miles per hour. It also has a pretty respectable magnetic field, but these are really non-propagating in that they don’t radiate. There is very slight radiation from things like that because the radiation resistance is of the order of micro-ohms. Wires are about ten meters apart, ten meters to a wavelength for sixty hertz (5000 km). From Boulder Dam to Los Angeles is about a quarter wavelength of that frequency, so figure it out from there. The moment is very small, so they don’t really radiate much, but the local field can be really juicy. I don’t recommend spending a great deal of time under it, but running under it with a car, which is basically a Faraday cage, won’t hurt anything. With running a telephone line in that dense fifty- or sixty-hertz field, of course it would hum like a bunch of bees, so they did play games to twist and try to help that. </p>
  
The thing that really saved their bacon was the sheath cable. They started putting everything in these shielded multi-pairs. There is a whole flock of pairs inside of them, maybe 200 or 300 greatly twisted pairs. This is something that the Dr. Paul I was telling you about investigated in great detail, how much twisting, what it did to have two pairs going like this, and how you could twist it. The mathematics that he gets into is pretty busy at times, too. They also have metallized mylar films around them to keep them from talking to each other. One twists one way and the other in the other direction so they don’t talk to each other. The shielding kept the AC out of their hair, and they are more at peace now. When everybody was using open wiring, you can see it in some places yet, they go along these wooden pole lines and they will have three phase AC on the top and then they will have a couple of cross arms, and a half dozen pairs of open telephone or telegraph wire below. This is the technique that was also used by the railroads, in their own right-of-way. That was telegraph. Almost from the beginning but not quite, the power companies ran what they call carrier current signaling on the power lines, but they don’t do it on the extra-high voltage lines.  
+
<p>The thing that really saved their bacon was the sheath cable. They started putting everything in these shielded multi-pairs. There is a whole flock of pairs inside of them, maybe 200 or 300 greatly twisted pairs. This is something that the Dr. Paul I was telling you about investigated in great detail, how much twisting, what it did to have two pairs going like this, and how you could twist it. The mathematics that he gets into is pretty busy at times, too. They also have metallized mylar films around them to keep them from talking to each other. One twists one way and the other in the other direction so they don’t talk to each other. The shielding kept the AC out of their hair, and they are more at peace now. When everybody was using open wiring, you can see it in some places yet, they go along these wooden pole lines and they will have three phase AC on the top and then they will have a couple of cross arms, and a half dozen pairs of open telephone or telegraph wire below. This is the technique that was also used by the railroads, in their own right-of-way. That was telegraph. Almost from the beginning but not quite, the power companies ran what they call carrier current signaling on the power lines, but they don’t do it on the extra-high voltage lines. </p>
  
The thing that stopped them from doing that is the price of the capacitor. When you go and grab a hold of a 750,000 volt line you do it with a great deal of finesse, and do you know what the price of a 0.01 capacitor to tie onto this thing would look like? Those they used to tap on the 161,000-volt lines are pretty big. You would think that there is some kind of a transformer because there is a great big insulator. But the capacitor is a little oil-filled thing inside a can, but to stand up against the voltage it has to be pretty high. Now the carrier current was, at first primarily, common mode. That is, they got on one line with an earth turn, so that all wires in the lines in the three-way-system were either inductively coupled. The power that they use is fairly low, about one watt, except when there are calls on the line and the thing jumps up to ten watts. The common mode ones radiate somewhat but they are not too bad. The frequencies that they use ran from 25 kHz to about 490, and some of the experimenters on the low frequency (VLF) band down here, especially in New Jersey, were using the Edison Company’s carrier current signal as a frequency standard. They tuned it back off about 10 kHz and were running one watt into fifty feet of cable, and this works out to be less than 100 microwatts in the Effective Radiated Power (ERP). Most of the energy is low. The EHV lines on the 365 kVz, and also on the 161’s, have what is called the static drain wire, the lightening protection devices, running along. These things are grounded at every tower, but in the newer construction they don’t ground them directly. They do it through a gap and the gap is set at about 5 kVz, so if lightning comes in, it jumps the gap, goes to ground, and behaves itself. It doesn’t fry the substation. What they are using now is a differential mode. They put the carrier current signal on that thing as a parallel transmission line using two static drain links and they have even less radiation leakage from those.  
+
<p>The thing that stopped them from doing that is the price of the capacitor. When you go and grab a hold of a 750,000 volt line you do it with a great deal of finesse, and do you know what the price of a 0.01 capacitor to tie onto this thing would look like? Those they used to tap on the 161,000-volt lines are pretty big. You would think that there is some kind of a transformer because there is a great big insulator. But the capacitor is a little oil-filled thing inside a can, but to stand up against the voltage it has to be pretty high. Now the carrier current was, at first primarily, common mode. That is, they got on one line with an earth turn, so that all wires in the lines in the three-way-system were either inductively coupled. The power that they use is fairly low, about one watt, except when there are calls on the line and the thing jumps up to ten watts. The common mode ones radiate somewhat but they are not too bad. The frequencies that they use ran from 25 kHz to about 490, and some of the experimenters on the low frequency (VLF) band down here, especially in New Jersey, were using the Edison Company’s carrier current signal as a frequency standard. They tuned it back off about 10 kHz and were running one watt into fifty feet of cable, and this works out to be less than 100 microwatts in the Effective Radiated Power (ERP). Most of the energy is low. The EHV lines on the 365 kVz, and also on the 161’s, have what is called the static drain wire, the lightening protection devices, running along. These things are grounded at every tower, but in the newer construction they don’t ground them directly. They do it through a gap and the gap is set at about 5 kVz, so if lightning comes in, it jumps the gap, goes to ground, and behaves itself. It doesn’t fry the substation. What they are using now is a differential mode. They put the carrier current signal on that thing as a parallel transmission line using two static drain links and they have even less radiation leakage from those. </p>
  
 
=== Ground Wave Emergency Network  ===
 
=== Ground Wave Emergency Network  ===
  
'''Smith:'''  
+
<p>'''Smith:''' </p>
  
When the ground wave emergency network for the Air Force a few years ago in Pueblo, Colorado went on-line there was an interference problem. The people who were doing the EMC analysis for the 500 kV line to 161 kV and from then to the domestic voltages of 2,300 and 660 and 220 and so on assumed a straight line between the substations, only they don’t go straight. The GWEN Station, instead of being fourteen miles away from the high line, was a little less than a mile. At this point Murphy takes charge of the whole project. The GWEN stations are LF and they picked a frequency that would be within 1 kHz of the operating frequency of this carrier current system. These carrier current systems are pretty busy, so when you get an interference problem you are going to know it. They carry a lot of data. There is a voice channel, and a voice receiver has very tight skirts at the pass band that chops off nearly dead at 500 and 2500 Hz. So it will handle normal voice. Then they got some auxiliary channels that they run tele-type through, and they are running a lot of data on the status of the system, so they shuttle back and forth. The system management of power companies is very sophisticated, with a lot of computer-driven equipment. It has load balancing and switching; the power is routed and re-routed. When the GWEN Station came on the air, there was a persistent 2 kH squeal. They were within about 2 kH of the carrier because they use an “H” mode which is a side band with carrier. The carrier is actually a break wire scheme. So if that carrier disappears, then the system is in a state of fault.  
+
<p>When the ground wave emergency network for the Air Force a few years ago in Pueblo, Colorado went on-line there was an interference problem. The people who were doing the EMC analysis for the 500 kV line to 161 kV and from then to the domestic voltages of 2,300 and 660 and 220 and so on assumed a straight line between the substations, only they don’t go straight. The GWEN Station, instead of being fourteen miles away from the high line, was a little less than a mile. At this point Murphy takes charge of the whole project. The GWEN stations are LF and they picked a frequency that would be within 1 kHz of the operating frequency of this carrier current system. These carrier current systems are pretty busy, so when you get an interference problem you are going to know it. They carry a lot of data. There is a voice channel, and a voice receiver has very tight skirts at the pass band that chops off nearly dead at 500 and 2500 Hz. So it will handle normal voice. Then they got some auxiliary channels that they run tele-type through, and they are running a lot of data on the status of the system, so they shuttle back and forth. The system management of power companies is very sophisticated, with a lot of computer-driven equipment. It has load balancing and switching; the power is routed and re-routed. When the GWEN Station came on the air, there was a persistent 2 kH squeal. They were within about 2 kH of the carrier because they use an “H” mode which is a side band with carrier. The carrier is actually a break wire scheme. So if that carrier disappears, then the system is in a state of fault. </p>
  
The penetrating squeal was very irritating to the people operating the substation. The colonel in charge of the ground wave emergency network for the Air Force was down the hall from me. He came in and wanted to know, “Dr. Smith, what can we do for this?” I said, “Well, I know what the problem what is. You know what you can do? You can hire old men who can’t hear 2 kH.” The colonel wasn’t too amused with that one. It was early in the program and I said the obvious thing to do was just move that thing 3 kHz or more one way or the other. Then you are out of the pass band and the system won’t even pay any attention to it. Frequency management was the basic tool for solving the interference problem and that’s why the EMC Society has had a standing committee working on frequency management for years. Frequency management is getting tighter because more and more people want to get into the spectrum and then on top of that you have incidental radiation from computers.  
+
<p>The penetrating squeal was very irritating to the people operating the substation. The colonel in charge of the ground wave emergency network for the Air Force was down the hall from me. He came in and wanted to know, “Dr. Smith, what can we do for this?” I said, “Well, I know what the problem what is. You know what you can do? You can hire old men who can’t hear 2 kH.” The colonel wasn’t too amused with that one. It was early in the program and I said the obvious thing to do was just move that thing 3 kHz or more one way or the other. Then you are out of the pass band and the system won’t even pay any attention to it. Frequency management was the basic tool for solving the interference problem and that’s why the EMC Society has had a standing committee working on frequency management for years. Frequency management is getting tighter because more and more people want to get into the spectrum and then on top of that you have incidental radiation from computers. </p>
  
 
=== Computer Radiation Leakage  ===
 
=== Computer Radiation Leakage  ===
  
'''Smith:'''  
+
<p>'''Smith:''' </p>
  
Computers are notorious for leakage. The computers, themselves are good, it’s the local area networks that leak. The LAN is a net that ties all the computers in a complex to the central computer lab. That is OK, but the only trouble is that people use cheap cable. The computers are fine, but their radiation can be picked up and decoded quite easily. Even with poor cable it is possible to still suppress radiation by doing some things to it. They could put some ferrite loading in various places, which does not interfere with the operation of the net but would suppress the radiation. It is a labor intensive “fix.”  
+
<p>Computers are notorious for leakage. The computers, themselves are good, it’s the local area networks that leak. The LAN is a net that ties all the computers in a complex to the central computer lab. That is OK, but the only trouble is that people use cheap cable. The computers are fine, but their radiation can be picked up and decoded quite easily. Even with poor cable it is possible to still suppress radiation by doing some things to it. They could put some ferrite loading in various places, which does not interfere with the operation of the net but would suppress the radiation. It is a labor intensive “fix.” </p>
  
'''Aspray:'''  
+
<p>'''Aspray:''' </p>
  
What problem is the radiation causing right now?  
+
<p>What problem is the radiation causing right now? </p>
  
'''Smith:'''  
+
<p>'''Smith:''' </p>
  
Well, they had an amateur radio operator complained about us at MITRE because he was trying to reach the Stone ham repeater on top of the White Memorial Hospital, from the Middlesex Turnpike in Bedford, MA. He was a hundred to two or three hundred yards away from the nearest MITRE building and he could not open the repeater because of the interference from something in the area that was leaking on the two meter amateur band. This is highly illegal; in fact the local ham repeater association shut down a number of channels of the cable company because they were leaking into the 144 to 148 megahertz band. That’s about 600, and they have some political swat when there are that many. Fortunately for everybody’s sanity, the guy was also an employee at MITRE and I was president of the ham club at the time and had heard about this, so we started looking into it. We found out that it was leakage from a computer. They said it wasn’t processing classified information and we said, “What does that have to do anything?” We were able to get rid of the problem before the FCC got in on it. That is not only an interference problem which I think the EMC society is aware of; I have heard some talk in some private conversations, and there has been a paper or two addressing this inadvertent data leakage. The security is terrible. This is I think one of the major areas for the EMC community and IEEE and its sister organizations in other groups are going to have to address in more depth as time goes on.  
+
<p>Well, they had an amateur radio operator complained about us at MITRE because he was trying to reach the Stone ham repeater on top of the White Memorial Hospital, from the Middlesex Turnpike in Bedford, MA. He was a hundred to two or three hundred yards away from the nearest MITRE building and he could not open the repeater because of the interference from something in the area that was leaking on the two meter amateur band. This is highly illegal; in fact the local ham repeater association shut down a number of channels of the cable company because they were leaking into the 144 to 148 megahertz band. That’s about 600, and they have some political swat when there are that many. Fortunately for everybody’s sanity, the guy was also an employee at MITRE and I was president of the ham club at the time and had heard about this, so we started looking into it. We found out that it was leakage from a computer. They said it wasn’t processing classified information and we said, “What does that have to do anything?” We were able to get rid of the problem before the FCC got in on it. That is not only an interference problem which I think the EMC society is aware of; I have heard some talk in some private conversations, and there has been a paper or two addressing this inadvertent data leakage. The security is terrible. This is I think one of the major areas for the EMC community and IEEE and its sister organizations in other groups are going to have to address in more depth as time goes on. </p>
  
As for encryption and decryption, the banks are already doing that. That merely says that they are on the air, and unless you have some way of getting at the code, you can’t get the information. If they are radiating then there is also the possibility to jam it. I think you are going to see some mischief from that direction when they really get on to the fact that they are capable of causing some serious trouble. Some years ago, the Navy sent through a classified inquiry about a device that was supposed to simulate an EMP event. They wanted to make the Navy Russian trawlers back off. Some of us had the poor grace to point out that they would kill their own electronics first. So anyway that was one of the things. I don’t know whether I have made any sense or not.  
+
<p>As for encryption and decryption, the banks are already doing that. That merely says that they are on the air, and unless you have some way of getting at the code, you can’t get the information. If they are radiating then there is also the possibility to jam it. I think you are going to see some mischief from that direction when they really get on to the fact that they are capable of causing some serious trouble. Some years ago, the Navy sent through a classified inquiry about a device that was supposed to simulate an EMP event. They wanted to make the Navy Russian trawlers back off. Some of us had the poor grace to point out that they would kill their own electronics first. So anyway that was one of the things. I don’t know whether I have made any sense or not. </p>
  
'''Aspray:'''  
+
<p>'''Aspray:''' </p>
  
Well, it has been helpful.  
+
<p>Well, it has been helpful. </p>
  
 
=== History of Radio Frequency Interference  ===
 
=== History of Radio Frequency Interference  ===
  
'''Smith:'''  
+
<p>'''Smith:''' </p>
  
Radio frequency interference goes back to sometime in the last Ice Age. If you are really looking for some really early history, the American Radio Relay League would be a good place to start. They have history buffs running loose down there too. The Connecticut Wireless Association maintains a museum of antique radio apparatus some of which they have. A good friend of ours who worked for me at GTE for many years used to teach down at Harvard at one time. He was something of a curmudgeon and hardly anyone could stand him. He used to refer to some of the other guys on the air, on the six-meter band, as “kinky-headed manure-noggins.” His sons neither of whom were amateur people, and they didn’t know anything about it. When he passed on, the sons asked some of us to come and look over his equipment. Some of his apparatus had some value, but most of it was junk. One of the things I found in his basement was a spark gap transmitter. It wasn’t in working order but it was an honest-to-God tooth-wheeled gap spark transmitter. I told his son, “Do you know what that thing is? The people with the Connecticut Wireless Association would love had to have it for their museum.” I think they got it. Of course, the thing itself was beyond repair, but there were parts in it that they could use for other things. A spark gap transmitter had a band that went from “DC to daylight” and a little beyond: Class-B modulation is a “no no,” and that was what they did. It’s no surprise the amateur community probably bumped into interference before anybody else. But the pros were into it by the latter part of the 1920s and that’s when the Hoover Commission came in and set up the bands.  
+
<p>Radio frequency interference goes back to sometime in the last Ice Age. If you are really looking for some really early history, the American Radio Relay League would be a good place to start. They have history buffs running loose down there too. The Connecticut Wireless Association maintains a museum of antique radio apparatus some of which they have. A good friend of ours who worked for me at GTE for many years used to teach down at Harvard at one time. He was something of a curmudgeon and hardly anyone could stand him. He used to refer to some of the other guys on the air, on the six-meter band, as “kinky-headed manure-noggins.” His sons neither of whom were amateur people, and they didn’t know anything about it. When he passed on, the sons asked some of us to come and look over his equipment. Some of his apparatus had some value, but most of it was junk. One of the things I found in his basement was a spark gap transmitter. It wasn’t in working order but it was an honest-to-God tooth-wheeled gap spark transmitter. I told his son, “Do you know what that thing is? The people with the Connecticut Wireless Association would love had to have it for their museum.” I think they got it. Of course, the thing itself was beyond repair, but there were parts in it that they could use for other things. A spark gap transmitter had a band that went from “DC to daylight” and a little beyond: Class-B modulation is a “no no,” and that was what they did. It’s no surprise the amateur community probably bumped into interference before anybody else. But the pros were into it by the latter part of the 1920s and that’s when the Hoover Commission came in and set up the bands. </p>
  
 
=== Wartime Jamming and Electronics  ===
 
=== Wartime Jamming and Electronics  ===
  
'''Aspray:'''  
+
<p>'''Aspray:''' </p>
  
When did the military services first get interested?  
+
<p>When did the military services first get interested? </p>
  
'''Smith:'''  
+
<p>'''Smith:''' </p>
  
World War I. The Germans caught on to what our side was doing and started jamming. So the electronic warfare started with World War I. To get rid of that when all that started, we started damping and trying to narrow the band up, and all kinds of stuff like that. So it really goes back to that day. During the 1920s not much of anything was done by the military because the United States wasn’t much interested in the military. The Army was down to less than a hundred thousand men. In the Navy most of the ships were mothballed and tied up and some of them were sunk. The aviation people were trying to convince the military that Navy ships should have airplanes on them. At that time, most of the admiral flag rank officers had sailed in Civil war-type monitors. Monitors were the top of the line; there was a famous duel at that time. These fly guys threw the bomb down the stack of the battleship and sank it. Radio was just a nice name. The United States Army Signal Corps was paying more attention because they were developing portable field-type apparatus. The old BC-10 was a terrible-looking thing. It had some tungsten filament tubes in it. When I went to Fort Monmouth the first thing they did was introduce us to this. I was a corporal at that time. If you had a stripe or two you were stuck; if you didn’t then you could duck a lot of responsibility.  
+
<p>World War I. The Germans caught on to what our side was doing and started jamming. So the electronic warfare started with World War I. To get rid of that when all that started, we started damping and trying to narrow the band up, and all kinds of stuff like that. So it really goes back to that day. During the 1920s not much of anything was done by the military because the United States wasn’t much interested in the military. The Army was down to less than a hundred thousand men. In the Navy most of the ships were mothballed and tied up and some of them were sunk. The aviation people were trying to convince the military that Navy ships should have airplanes on them. At that time, most of the admiral flag rank officers had sailed in Civil war-type monitors. Monitors were the top of the line; there was a famous duel at that time. These fly guys threw the bomb down the stack of the battleship and sank it. Radio was just a nice name. The United States Army Signal Corps was paying more attention because they were developing portable field-type apparatus. The old BC-10 was a terrible-looking thing. It had some tungsten filament tubes in it. When I went to Fort Monmouth the first thing they did was introduce us to this. I was a corporal at that time. If you had a stripe or two you were stuck; if you didn’t then you could duck a lot of responsibility. </p>
  
They assigned a fellow to me by the name of Gotleib (sic) who could have been a model for Sad Sack. His uniform hung on him on odd ways but he was an awfully sweet person, and totally inept when it came to electronics. One day I asked him, “How in the name of common sense did you ever get stuck in radio?” He said, “I work in it. My civilian job was working in radio,” and I said, “What?” He said, “I am a studio organist.” I was a good friend of the chaplain at the time, and the chaplain had just lost his assistant. The job called for the rank of staff sergeant and the chaplain was a colonel. I said, “This guy is going to kill himself. He is in there and he doesn’t know anything about electricity and I am just afraid he is going to get electrocuted!” I also said that he was a musician. The chaplain said, “Send him around.” It turns out that this Jewish kid knew all of the hymns of any church you wanted to name by heart. He was good and the chaplain snapped him up and saved his life. We had some real electromagnetic hazards there. We went on overseas and I put a lot of equipment in all across North Africa into Turkey and so on. The equipment we had in those days was Super Pros and it just racked them up one after the other. We started listening to the Russians when the war was over, and got them annoyed. One other adventure we had at that time that was really not electromagnetic. I guess it’s incompatibility, if you want to call it that.  
+
<p>They assigned a fellow to me by the name of Gotleib (sic) who could have been a model for Sad Sack. His uniform hung on him on odd ways but he was an awfully sweet person, and totally inept when it came to electronics. One day I asked him, “How in the name of common sense did you ever get stuck in radio?” He said, “I work in it. My civilian job was working in radio,” and I said, “What?” He said, “I am a studio organist.” I was a good friend of the chaplain at the time, and the chaplain had just lost his assistant. The job called for the rank of staff sergeant and the chaplain was a colonel. I said, “This guy is going to kill himself. He is in there and he doesn’t know anything about electricity and I am just afraid he is going to get electrocuted!” I also said that he was a musician. The chaplain said, “Send him around.” It turns out that this Jewish kid knew all of the hymns of any church you wanted to name by heart. He was good and the chaplain snapped him up and saved his life. We had some real electromagnetic hazards there. We went on overseas and I put a lot of equipment in all across North Africa into Turkey and so on. The equipment we had in those days was Super Pros and it just racked them up one after the other. We started listening to the Russians when the war was over, and got them annoyed. One other adventure we had at that time that was really not electromagnetic. I guess it’s incompatibility, if you want to call it that. </p>
  
In Ankara, the British ambassador office one of his staff with a problem. The only thing that kept this man sane, was his ability to listen to BBC in the evening. That was his lifeline. He had a Marconi receiver, and they had in those days a form of electrolytic capacitor that actually had liquid in it, and this thing apparently got shorted through. He kept listening to BBC through this hum and finally one day he had an old-fashioned steam boiler explosion where this can exploded, broke the tubes, and scattered corrosive liquid all over the whole thing. We were busy installing those Hammerlund receivers. We put them on the guise that we were helping the Turkish government upgrade its airports for both the civilian and the military. The real reason we were putting them in was to listen in on Soviet Union and they knew it. This British officer looks brought in his poor receiver and he says, “Can you Yanks do anything for it?” I was chief of the radio section, and I said, “No, that thing is beyond repair.” And the lieutenant says, “Give him one of the Super Pros.” It was pretty big, the size of a good-sized oven, and it had a power supply that contained a lot of iron. So we sent this poor guy off with his toy. After he was gone I went back to the office and said, “OK, sir. How are you going to explain this one?” He looks me straight in the eye and says, “Lost in combat.” By that time the war was on the other side of the world!  
+
<p>In Ankara, the British ambassador office one of his staff with a problem. The only thing that kept this man sane, was his ability to listen to BBC in the evening. That was his lifeline. He had a Marconi receiver, and they had in those days a form of electrolytic capacitor that actually had liquid in it, and this thing apparently got shorted through. He kept listening to BBC through this hum and finally one day he had an old-fashioned steam boiler explosion where this can exploded, broke the tubes, and scattered corrosive liquid all over the whole thing. We were busy installing those Hammerlund receivers. We put them on the guise that we were helping the Turkish government upgrade its airports for both the civilian and the military. The real reason we were putting them in was to listen in on Soviet Union and they knew it. This British officer looks brought in his poor receiver and he says, “Can you Yanks do anything for it?” I was chief of the radio section, and I said, “No, that thing is beyond repair.” And the lieutenant says, “Give him one of the Super Pros.” It was pretty big, the size of a good-sized oven, and it had a power supply that contained a lot of iron. So we sent this poor guy off with his toy. After he was gone I went back to the office and said, “OK, sir. How are you going to explain this one?” He looks me straight in the eye and says, “Lost in combat.” By that time the war was on the other side of the world! </p>
  
[[Category:People_and_organizations]] [[Category:Engineers]] [[Category:Inventors]] [[Category:Fields,_waves_&_electromagnetics|Category:Fields,_waves_&amp;_electromagnetics]] [[Category:Electromagnetic_compatibility]] [[Category:Electromagnetic_shielding]] [[Category:Interference]] [[Category:Interference_elimination]] [[Category:Signals]] [[Category:Signal_detection]] [[Category:Radar_detection]] [[Category:Culture_and_society]] [[Category:Defense_&_security|Category:Defense_&amp;_security]] [[Category:World_War_II]] [[Category:IEEE]] [[Category:Standards]] [[Category:Prominent_members]]
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[[Category:Fields, waves & electromagnetics|Smith]] [[Category:Defense & security|Smith]] [[Category:People and organizations|Smith]] [[Category:Engineers|Smith]] [[Category:Inventors|Smith]] [[Category:Electromagnetic compatibility|Smith]] [[Category:Electromagnetic shielding|Smith]] [[Category:Interference|Smith]] [[Category:Interference elimination|Smith]] [[Category:Signals|Smith]] [[Category:Signal detection|Smith]] [[Category:Radar detection|Smith]] [[Category:Culture and society|Smith]] [[Category:World War II|Smith]] [[Category:IEEE|Smith]] [[Category:Standards|Smith]] [[Category:Prominent members|Smith]] [[Category:Automation|Smith]] [[Category:Variable control|Smith]] [[Category:Magnetic variables control|Smith]] [[Category:News|Smith]]

Latest revision as of 15:37, 6 August 2012

Contents

About Chester Smith

Dr. Chester Smith's career focused on the problem of electric interference. Smith was part of the early IEEE Electromagnetic Compatibility Society (EMC), and has witnessed the evolution of interference control from World War One to the present. During World War Two, Smith served overseas with the U.S. Army Signal Corps, working on naval communications and interference problems. After the war, he helped develop national standards for controlling interference effects and helped eliminate interference in the Air Force's ground wave emergency network.

The interview does not cover Smith's background or education, but instead begins rather suddenly with his descriptions of the EMC. Smith focuses on the history of interference control, particularly the work of the EMC and the American National Standards Institute. He credits amateur radio operators' contributions to the field, and gives examples of how frequency management and equipment tuning eliminate interference problems. Smith also discusses computer leakage, electromagnetic pulse effects, and electronic jamming. He recommends other people to interview, and closes with his reminiscences of World War Two and the first days of the Cold War.

About the Interview

Chester Smith: An Interview Conducted by William Aspray, IEEE History Center, April 8, 1993

Interview # 151 for the IEEE History Center, The Institute of Electrical and Electronics Engineers, Inc.

Copyright Statement

This manuscript is being made available for research purposes only. All literary rights in the manuscript, including the right to publish, are reserved to the IEEE History Center. No part of the manuscript may be quoted for publication without the written permission of the Director of IEEE History Center.

Request for permission to quote for publication should be addressed to the IEEE History Center Oral History Program, 39 Union Street, New Brunswick, NJ 08901-8538 USA. It should include identification of the specific passages to be quoted, anticipated use of the passages, and identification of the user.

It is recommended that this oral history be cited as follows:

Chester Smith, an oral history conducted in 1993 by William Aspray, IEEE History Center, New Brunswick, NJ, USA.

Interview

Interviewee: Chester Smith

Interviewer: William Aspray

Place Unknown

Date: April 8, 1993

Electromagnetic Control Society

Smith:

The EMC Society started as the radio frequency interference group of IRE. The guiding light in those days was Rexford Daniels, who lived over here in Concord, Massachusetts, and he passed on three or four years ago. A couple of other people who are still around are Gene Knowles in Renton, Washington and Leonard Thomas. Len lives in Baltimore, Maryland. I would have to look up his address for you. Both of these people were in on the earliest days of the EMC society and I got involved in it a little bit later.

There was also someone by the name of Robert Berkovits, who now (1993) works with Grumman on Long Island, NY. Bob is one of those people who just never gives up. He kept the local chapter of the radio frequency interference group going, and when the IRE and the AIEE merged it became the electromagnetic compatibility group. I was the first chairman of the new merged chapter of Aerospace Electronic Systems (AES). To keep the Boston IEEE section from putting it out of business because they didn’t have enough meetings in a year, Bob used to bug me for joint meetings with AES. So we were holding joint meetings after the merger, and all during the 1960s. I moved into the EMC technology area, myself. The major concern then was effects of electromagnetic pulse and other nuclear phenomena on electronics. There were comments about some of the earlier studies in those newsletters that I sent you. You can find some of Rex Daniels’ original comments about it. Later there were some of the pioneering studies on cable coupling by Clayton Paul, a professor down at the University of Kentucky. He did a lot of early work on that and he is still very active.

Aspray:

What’s the issue there?

Smith:

Wire coupling. I think it really got started as an outgrowth of studies by the telephone people because they were very interested in keeping their circuits free of cross-talk. So there was some early work done on that, but I don’t think they ever took it to the degree that Dr. Paul has with his studies. Who else would be a major pioneer?

On Fields, Myron Crawford at the Bureau of Standards is another person that you ought to talk to. The famous Crawford Cell is named after him. It is a TEM mode device for studying effects of fields on devices. Put your electronic widget in there and zap it! The field can be adjusted spacing from a low to high impedance type field or of course, it can be set to a straight transverse electromagnetic field (377Ω). That is another major area that needs attention. Another area when you talk about the history of electromagnetics interference control is frequency management. Now EMC-S has a whole task group and it has been active for many years. I was involved with that group for a while in the mid-1970s. One way among others to control electromagnetic interference is to control the way the spectrum is managed. We dealt with such things as cross-polarization effects, time-sharing, and this whole list.

Military Impetus for EMC Research

Aspray:

How did the Society come about in the first place? Where were most of the people drawn from?

Smith:

The big push really for the creation of the Society in the first place came from two major military sources: the Air Force and the Navy. The problem being that the equipment of these services can be pretty cramped as far as space which is conducive of cross-coupling. The other military people, the Army and the Marines, didn’t seem to be too perturbed about it. They spread out more. The civilian market is just now beginning to really wake up and we are getting quite a bit of static out of the European people. But the major push for it came from the military. You have to get Len Thomas’s version of it. He tells the story about making some design measurements with a field strength meter and antennas in a field near the Navy boot training station in San Diego. They were out measuring and taking readings on the fields. A Navy captain, a four-striper, came out there and wanted to know what they were doing. He said, “We are making field strength measurements.” The captain looked at him kind of funny and then stomped on the ground a few times, and he said, “This field looks strong enough to me.”

Interference on board ship was a major driver because they were stacking electronic boxes and antennas were right next to each other, all near field coupling, and the thing would get to be a hairy mess. The Air Force was not far behind them. Both services, particularly the Air Force, became very interested in the electromagnetic pulse effects. That is because they would presumably have to fly near where something like that might happen. That is another major area where an important function created a lot of interest.

Civilian markets have really taken off recently over the last five or six years. I have spent some time on American National Standards Institute’s C63 Committee. Germany is probably the tightest about interference effects. The Federal Communications Commission has had authorization in the Goldwater-Vanick-Wirth Bill of 1982 to write immunity standards, but the bill did not mandate it. So all the Federal Communications Commission’s rules and regulations on it deal only with emissions. However, ANSI, IEEE and jointly C63 sub-committee 5 chaired by Don Heirman of AT&T labs in Holmdel, are working on the immunity standard. The FCC participates in it, chiefly in the person of Arthur Wall. Also they have taken some steps to answer people who are complaining about interference effects, but mainly they (the FCC) pushed it off on the manufacturers. If one complains loudly enough maybe they (the manufacturer) will do something. Most of the people don’t worry about it or just live with it. I read a paper a year ago at a meeting in Denver on the domestic EMC standard. It dealt with some rather innocuous things like those little colorful sprinkles you see on your television set when somebody turns on a hair dryer or a mixer or something. Those are just annoying, but it is not so funny when it gets into the navigation equipment of an airliner.

Aspray:

I could imagine.

Smith:

We found that with the low frequencies (a few KHz to MHz) primarily conducted, we weren’t seeing too much in the way of radiation. But when the frequency was up to the high end of HF and into VHF, it was by antenna-like structure, such as lead-ins and power cords almost entirely radiated and then picked up. It is also common mode.

Aspray:

What other companies or government organizations that were interested in these kinds of problems made studies of them?

Smith:

The Army got very interested in the mid-1960s in the effect of electromagnetic pulses on their fielded equipment. There has always of course been the business of the outgrowth of the radar and electronic warfare area. Would your equipment stand up against a radar set? So they played a lot of games with that. Some of that stuff is still pretty highly classified.

Aspray:

Do you know where it was done? What locations in the Army?

Smith:

Some of it was done here at MIT. Most of the major universities had a finger in the pie at one time or another. Ohio State did an awful lot of work. They were looking at the antenna-to-antenna kind of coupling. How to couple, how to decouple, generally how to handle nuclear interference problems. Syracuse University was big in it too; they were involved with the IEMCAP program. The IEMCAP is Interference and Electromagnetic Control Analysis Program. It came out of Rome [NY] Development Center at the Griffiss Air Base. The initial work was done by McDonnell-Douglas in St. Louis, and the program was extremely bulky and very awkward to use when Rome Development Center asked for the models for antenna-to-antenna coupling and things like that. The company took an attitude that the models were proprietary. People at RADC gave a reverse engineering contract to Don Wiener and his outfit at Syracuse to go back over the thing. For example it didn’t handle switching well. It used a power series for the electronic and analytical modeling. By the time you got enough turns to make this square wave a good amount of computer time had been burned up. I was talking to Al Leber who was sort of the grandfather of this whole thing, he is a Rand guy from the West Coast. He is the one who put RADC up to doing this in the first place. I guess it was that extra Manhattan that did it. I told him that the antenna coupling model was wrong. What they did was put the antenna on top of the airplane and another one on the bottom. If you tied a string for the shortest possible path, that’s what they used. Then they treated it as if it were a free space, Friis-type coupling, as if these antennas were in free space looking at each other. Well, that sounds like a worst-case example, and unfortunately it is not. There are corners in airplane structure, in the tails and other places. The shortest path may not represent the tightest coupling. They followed that up with a contract to Bill Duff at Atlantic Research. His group rewrote that part of the IEMCAP code to couple by the tightest path, not necessarily by the shortest. I felt pretty good about that one. That was the major effort that went into it. That was a big program and it is still around. Kaman Sciences in Utica has copies of that program now so that any government contracting company or educational institution can get a copy of it. They also have it revised to run on a PC.

Also, a version of it has been re-worked by Lawrence Livermore Labs, and that’s available from the Naval Post-Graduate Center in Monterey, CA. They have format now so instead of computer paper stacked four feet high, the output comes out on a single 8 1/2 x 11 inch sheet. You list all the electronic goodies down one side and across the top, and it sorts itself. Any interference within ten dB of that a pre-set threshold marks. It can think a candidate list of ten thousand or a hundred thousand possible interferences down to maybe less than one hundred. It is not a very smart program in the sense that it has a tendency to yell wolf when there is no wolf. In closer analysis of the areas where it says to look, most of them will go away and end up with at least five or ten. Those are the areas that require redesign. So that’s about what I know about that. I have used the program. The biggest problem with it is that it costs quite a bit to get the baseline in. Once the baseline is set, it’s not much trouble to modify it, to try changes, to move things around. It takes a big machine; an IBM 370 or something of that sort would run it. Jerry Caprero (sic) at Kaman Sciences says he has a cut-down version that would run on a good-sized PC; a 386 or 486 can handle it quite happily, but it is slow compared to big frames. They left out some things that don’t trouble most people. In the original program they had some routine that calculated the electrical disturbances when a satellite crosses the magnetopause, but most of us don’t need that. It is not something we see in the average airplane or ground vehicle.

Civilian Concerns with EMC

Smith:

The civilian side of EMC will be a biggie from now on I think, for two reasons: first, the military is beginning to wake up with the fact that they won’t be inspecting everything since they found that that costs too much. I don’t know the relative changes and costs. It’s like half again or twice as much for the absolutely the same identical item. I remember pricing some transmitters. One was for an over-the-counter item at most radio retail stores, Radio Shack for example. It cost at that time about $250 to buy it over-the-counter. The military price was about $400. The company said that they had to do that because the government asked for a long list of tests and checks. Consequently they couldn’t afford to sell it to the government at the lower price. The FCC is tightening up the electromagnetic requirements on civilian items. Now immunity standards are being prepared by ANSI. These are being coordinated with the European ones. CISPR’s [International Special Committee on Radio Interference] set of standards are strictly advisory. Even though they are advisory, manufacturers ignore them at their peril. Fortunately, a number of countries have adopted them as law. Belgium and Spain for example bought CISPR regulations and they are now the law of the land. The Germans and the British have always had their own. The German rules are pretty stiff. The penalty for trying to take a piece of electronic equipment into Germany that does not meet their requirements is not only a big fine, but the government may confiscate your shipment and destroy it. So this has strongly motivated people to meet the rules.

The latest goings-on in the EMC field... Well, IEEE isn’t the only outfit that’s been involved in the Society of Automotive Engineers. The so-called SAE-4 Committee has been dealing with interference ever since people started putting Motorola radios in cars. At first ignition noise all but made the radios useless if the transmitters were not nearby. The remedy was to use carbon filament high-tension wires to go to the spark plugs. Replacing the wire with a filament of carbon cut down most of the noise without interfering with the spark action. Now that there are a lot of other electronic goodies going into cars, two-way radio, cellular radio...

Aspray:

Cellular phones, right.

Hazards of Electromagnetic Fields

Smith:

You have phones and that sort of thing. The other major area that you should consider that has really boiled over now is personnel hazards with electromagnetic fields. That famous Denver study by that woman doctor, I think was so badly controlled that it is next to worthless.

Aspray:

Have there been studies by your society?

Smith:

Yes, they are working on it. Almost every year at the symposium there will be two or three papers on it and sometimes they will hold sessions on five or six of them. There is a lot of overlap: the SAE 4, the ANSI, etc., have the same cast of characters. A lot of people on one committee are on another or they are working in the field and they know each other; it is a big club. Sometimes we meet in Washington and the next time somewhere else. It is almost a floating crap game: we are in Dallas, San Diego or something, but it is the same bunch of people. Herb Mertel is involved with international standards and I was looking at domestic EMC problems, antennas. The antenna people, standardizing test facilities it is the same group of people who float around. At one time they are the IEEE group, and the same bunch later meet as ANSI-C63. This tends to confuse everybody, but it is a lot of the same people. Bob Hoffman, for example, I know for a fact is on at least three of those committees. Don Heirman I know is nearly on every one of them.

Aspray:

Do you think that is good or bad?

Smith:

The good side to it is this: different parent organizations see the commonalty of the problems. That’s the good side. The bad side is that the thing is incestuous; the same people do all the same stuff.

American Radio Relay League

Aspray:

If you were to look way back in history, where were the first interference problems addressed?

Smith:

The American Radio Relay League was talking about that in 1927.

Aspray:

What was the context?

Smith:

The amateurs and the professionals were interfering, or the professionals were interfering with the hams and the hams vice-versa. This was the day when the vacuum tube was just beginning to get common. A lot of the rigs in those days were spark gap. One of the favorite rigs of the hams was the Ford Model T ignition coil. You know where the American Radio Relay League is headquartered. They are in Newington, Connecticut, at 225 Main Street. The executive vice-president is a man by the name of David Sumner. He is very personable and a very easy guy to talk to.

Some of the earliest papers that I have run across dealing with interference... 1927 through 1957, was thirty years before the pros began to really wake up. Then Rexford Daniels and some others began to wake up the professionals. The amateur fraternity had dealt with it. They are not a bunch of lightweights; you have a lot of Ph.D.’s among the radio amateurs. They have produced a lot of papers of the quality that one would really expect of a professional writer. To my personal knowledge the earliest paper dealing specifically and exclusively with radio interference was that 1927 paper in QST, their magazine. This goes back to Marconi himself; I think he and Herz must have had a problem. It goes way, way back.

Government Regulation

Aspray:

Did the government take a hand in this by regulation?

Smith:

Not right away. The regulations came later when the Hoover Commission set them up before Herbert Hoover was elected President. Mostly the pros were interfering with each other. Of course, public broadcasting was being promoted: KDKA was on the air, but not many other stations. The news people were getting information back and forth inter-continentally with very low frequency (VLF 30 - 300kHz), and they were using these huge antennas. The Beverage antenna for receiving and transmitting was not a very efficient device, but it is quite directional. They were communicating with Morse code, hence the NCW, and they had operators. That was also the same time when the secrecy provision in the international treaty was implemented. Of course, in following up on the Titanic problem, there was an international treaty that required the ships to carry radio. The generators, the electric lights, and so forth were big open-coil things with lots of sparks. I am sure if we burrowed around we could find some comments about interference in the early days.

Basically Hoover’s commission set up the bands. The low frequency bands, the MF broadcast band that ran from 550 to 1500 kHz. The amateurs were relegated to 200 meters, shorter wavelengths. When they started screwing around we found out that frequencies around fourteen to fifteen megahertz were going all over the world with only a few watts. Commercials began a rush in there and amateurs were restricted to set bands that were originally harmonic. The idea behind the harmonic was an interference problem; if someone on 160-meters (1700-2000 kHz) had a harmonic, it would land on the 80 meter band. From forty to twenty to ten, and then ten to five and finally two and a half meters; anything above that was fair game. That condition lasted until World War II broke out, but the idea behind it was that ham interference problem would only trouble with their own people. The American Radio Relay League’s magazine and a couple of other clubs began to publish articles on harmonic suppression and generally began to look into the technology of narrowing signal bandwidth. They were advocating crystal control and doing some interesting research on filters. The early filters were bulky things. They were made with wires, homemade coils and so on, but the things worked. One could put those things between the transmitter and the antenna and they pretty well cleaned up the signal. A lot of their 1930s articles on how to build circuits dealt with the issue of suppressing parasitic oscillations, which is a source of unwanted radiation. The amateur fraternity was about thirty years ahead of the pros when it came to formal recognition of the seriousness of interference and the technology for controlling it. Give them brownie points. Some of these guys were professors at MIT and other universities, like John Kraus, Professor Emeritus now at Ohio State. These people wrote a lot of the articles, so I am saying that they weren’t all backyard experimenters and high school kids just playing with flukes. They were pretty serious people.

Magnetic Fields and Telephone Lines

Aspray:

Were the telephone engineers interested in these issues early on?

Smith:

Yes, they were but they were keeping to themselves. If you go through the Bell System journal you can find that occasionally they talked about it. They were concerned with circuit cross talk and then they started this base band and then the harmonic band to get more lines on the same circuit.

Aspray:

I guess it was sometime in the 1930s there was a big lawsuit between the telephone companies and I think it was the utilities... I don’t remember if it was regular power transmission or railroad power that was interfering with telephone lines.

Smith:

All of them. Part of the problem was that their right-of-ways were limited. The municipalities controlled where they could put their lines. If the telephone company had its way of course, they would have been miles away, but the utilities, the municipalities and the county governments said, “You can run your pole line there, and the power company is running down there.” They were often times forced by government action to use the same poles. So then they started playing games about inverting every little bit; they twisted and rolled these things over to reduce the amount of coupling between them. The local quasi-static field around a power line is quite strong, and it may astonish you what the volts per meter under one of these lines is like. We have one going through Burlington into Lexington to a sub-station. It’s 365,000 volts phase to phase. That thing would put about 25,000 volts per meter where the cars run under it. No one stays in it very long, not at sixty-five miles per hour. It also has a pretty respectable magnetic field, but these are really non-propagating in that they don’t radiate. There is very slight radiation from things like that because the radiation resistance is of the order of micro-ohms. Wires are about ten meters apart, ten meters to a wavelength for sixty hertz (5000 km). From Boulder Dam to Los Angeles is about a quarter wavelength of that frequency, so figure it out from there. The moment is very small, so they don’t really radiate much, but the local field can be really juicy. I don’t recommend spending a great deal of time under it, but running under it with a car, which is basically a Faraday cage, won’t hurt anything. With running a telephone line in that dense fifty- or sixty-hertz field, of course it would hum like a bunch of bees, so they did play games to twist and try to help that.

The thing that really saved their bacon was the sheath cable. They started putting everything in these shielded multi-pairs. There is a whole flock of pairs inside of them, maybe 200 or 300 greatly twisted pairs. This is something that the Dr. Paul I was telling you about investigated in great detail, how much twisting, what it did to have two pairs going like this, and how you could twist it. The mathematics that he gets into is pretty busy at times, too. They also have metallized mylar films around them to keep them from talking to each other. One twists one way and the other in the other direction so they don’t talk to each other. The shielding kept the AC out of their hair, and they are more at peace now. When everybody was using open wiring, you can see it in some places yet, they go along these wooden pole lines and they will have three phase AC on the top and then they will have a couple of cross arms, and a half dozen pairs of open telephone or telegraph wire below. This is the technique that was also used by the railroads, in their own right-of-way. That was telegraph. Almost from the beginning but not quite, the power companies ran what they call carrier current signaling on the power lines, but they don’t do it on the extra-high voltage lines.

The thing that stopped them from doing that is the price of the capacitor. When you go and grab a hold of a 750,000 volt line you do it with a great deal of finesse, and do you know what the price of a 0.01 capacitor to tie onto this thing would look like? Those they used to tap on the 161,000-volt lines are pretty big. You would think that there is some kind of a transformer because there is a great big insulator. But the capacitor is a little oil-filled thing inside a can, but to stand up against the voltage it has to be pretty high. Now the carrier current was, at first primarily, common mode. That is, they got on one line with an earth turn, so that all wires in the lines in the three-way-system were either inductively coupled. The power that they use is fairly low, about one watt, except when there are calls on the line and the thing jumps up to ten watts. The common mode ones radiate somewhat but they are not too bad. The frequencies that they use ran from 25 kHz to about 490, and some of the experimenters on the low frequency (VLF) band down here, especially in New Jersey, were using the Edison Company’s carrier current signal as a frequency standard. They tuned it back off about 10 kHz and were running one watt into fifty feet of cable, and this works out to be less than 100 microwatts in the Effective Radiated Power (ERP). Most of the energy is low. The EHV lines on the 365 kVz, and also on the 161’s, have what is called the static drain wire, the lightening protection devices, running along. These things are grounded at every tower, but in the newer construction they don’t ground them directly. They do it through a gap and the gap is set at about 5 kVz, so if lightning comes in, it jumps the gap, goes to ground, and behaves itself. It doesn’t fry the substation. What they are using now is a differential mode. They put the carrier current signal on that thing as a parallel transmission line using two static drain links and they have even less radiation leakage from those.

Ground Wave Emergency Network

Smith:

When the ground wave emergency network for the Air Force a few years ago in Pueblo, Colorado went on-line there was an interference problem. The people who were doing the EMC analysis for the 500 kV line to 161 kV and from then to the domestic voltages of 2,300 and 660 and 220 and so on assumed a straight line between the substations, only they don’t go straight. The GWEN Station, instead of being fourteen miles away from the high line, was a little less than a mile. At this point Murphy takes charge of the whole project. The GWEN stations are LF and they picked a frequency that would be within 1 kHz of the operating frequency of this carrier current system. These carrier current systems are pretty busy, so when you get an interference problem you are going to know it. They carry a lot of data. There is a voice channel, and a voice receiver has very tight skirts at the pass band that chops off nearly dead at 500 and 2500 Hz. So it will handle normal voice. Then they got some auxiliary channels that they run tele-type through, and they are running a lot of data on the status of the system, so they shuttle back and forth. The system management of power companies is very sophisticated, with a lot of computer-driven equipment. It has load balancing and switching; the power is routed and re-routed. When the GWEN Station came on the air, there was a persistent 2 kH squeal. They were within about 2 kH of the carrier because they use an “H” mode which is a side band with carrier. The carrier is actually a break wire scheme. So if that carrier disappears, then the system is in a state of fault.

The penetrating squeal was very irritating to the people operating the substation. The colonel in charge of the ground wave emergency network for the Air Force was down the hall from me. He came in and wanted to know, “Dr. Smith, what can we do for this?” I said, “Well, I know what the problem what is. You know what you can do? You can hire old men who can’t hear 2 kH.” The colonel wasn’t too amused with that one. It was early in the program and I said the obvious thing to do was just move that thing 3 kHz or more one way or the other. Then you are out of the pass band and the system won’t even pay any attention to it. Frequency management was the basic tool for solving the interference problem and that’s why the EMC Society has had a standing committee working on frequency management for years. Frequency management is getting tighter because more and more people want to get into the spectrum and then on top of that you have incidental radiation from computers.

Computer Radiation Leakage

Smith:

Computers are notorious for leakage. The computers, themselves are good, it’s the local area networks that leak. The LAN is a net that ties all the computers in a complex to the central computer lab. That is OK, but the only trouble is that people use cheap cable. The computers are fine, but their radiation can be picked up and decoded quite easily. Even with poor cable it is possible to still suppress radiation by doing some things to it. They could put some ferrite loading in various places, which does not interfere with the operation of the net but would suppress the radiation. It is a labor intensive “fix.”

Aspray:

What problem is the radiation causing right now?

Smith:

Well, they had an amateur radio operator complained about us at MITRE because he was trying to reach the Stone ham repeater on top of the White Memorial Hospital, from the Middlesex Turnpike in Bedford, MA. He was a hundred to two or three hundred yards away from the nearest MITRE building and he could not open the repeater because of the interference from something in the area that was leaking on the two meter amateur band. This is highly illegal; in fact the local ham repeater association shut down a number of channels of the cable company because they were leaking into the 144 to 148 megahertz band. That’s about 600, and they have some political swat when there are that many. Fortunately for everybody’s sanity, the guy was also an employee at MITRE and I was president of the ham club at the time and had heard about this, so we started looking into it. We found out that it was leakage from a computer. They said it wasn’t processing classified information and we said, “What does that have to do anything?” We were able to get rid of the problem before the FCC got in on it. That is not only an interference problem which I think the EMC society is aware of; I have heard some talk in some private conversations, and there has been a paper or two addressing this inadvertent data leakage. The security is terrible. This is I think one of the major areas for the EMC community and IEEE and its sister organizations in other groups are going to have to address in more depth as time goes on.

As for encryption and decryption, the banks are already doing that. That merely says that they are on the air, and unless you have some way of getting at the code, you can’t get the information. If they are radiating then there is also the possibility to jam it. I think you are going to see some mischief from that direction when they really get on to the fact that they are capable of causing some serious trouble. Some years ago, the Navy sent through a classified inquiry about a device that was supposed to simulate an EMP event. They wanted to make the Navy Russian trawlers back off. Some of us had the poor grace to point out that they would kill their own electronics first. So anyway that was one of the things. I don’t know whether I have made any sense or not.

Aspray:

Well, it has been helpful.

History of Radio Frequency Interference

Smith:

Radio frequency interference goes back to sometime in the last Ice Age. If you are really looking for some really early history, the American Radio Relay League would be a good place to start. They have history buffs running loose down there too. The Connecticut Wireless Association maintains a museum of antique radio apparatus some of which they have. A good friend of ours who worked for me at GTE for many years used to teach down at Harvard at one time. He was something of a curmudgeon and hardly anyone could stand him. He used to refer to some of the other guys on the air, on the six-meter band, as “kinky-headed manure-noggins.” His sons neither of whom were amateur people, and they didn’t know anything about it. When he passed on, the sons asked some of us to come and look over his equipment. Some of his apparatus had some value, but most of it was junk. One of the things I found in his basement was a spark gap transmitter. It wasn’t in working order but it was an honest-to-God tooth-wheeled gap spark transmitter. I told his son, “Do you know what that thing is? The people with the Connecticut Wireless Association would love had to have it for their museum.” I think they got it. Of course, the thing itself was beyond repair, but there were parts in it that they could use for other things. A spark gap transmitter had a band that went from “DC to daylight” and a little beyond: Class-B modulation is a “no no,” and that was what they did. It’s no surprise the amateur community probably bumped into interference before anybody else. But the pros were into it by the latter part of the 1920s and that’s when the Hoover Commission came in and set up the bands.

Wartime Jamming and Electronics

Aspray:

When did the military services first get interested?

Smith:

World War I. The Germans caught on to what our side was doing and started jamming. So the electronic warfare started with World War I. To get rid of that when all that started, we started damping and trying to narrow the band up, and all kinds of stuff like that. So it really goes back to that day. During the 1920s not much of anything was done by the military because the United States wasn’t much interested in the military. The Army was down to less than a hundred thousand men. In the Navy most of the ships were mothballed and tied up and some of them were sunk. The aviation people were trying to convince the military that Navy ships should have airplanes on them. At that time, most of the admiral flag rank officers had sailed in Civil war-type monitors. Monitors were the top of the line; there was a famous duel at that time. These fly guys threw the bomb down the stack of the battleship and sank it. Radio was just a nice name. The United States Army Signal Corps was paying more attention because they were developing portable field-type apparatus. The old BC-10 was a terrible-looking thing. It had some tungsten filament tubes in it. When I went to Fort Monmouth the first thing they did was introduce us to this. I was a corporal at that time. If you had a stripe or two you were stuck; if you didn’t then you could duck a lot of responsibility.

They assigned a fellow to me by the name of Gotleib (sic) who could have been a model for Sad Sack. His uniform hung on him on odd ways but he was an awfully sweet person, and totally inept when it came to electronics. One day I asked him, “How in the name of common sense did you ever get stuck in radio?” He said, “I work in it. My civilian job was working in radio,” and I said, “What?” He said, “I am a studio organist.” I was a good friend of the chaplain at the time, and the chaplain had just lost his assistant. The job called for the rank of staff sergeant and the chaplain was a colonel. I said, “This guy is going to kill himself. He is in there and he doesn’t know anything about electricity and I am just afraid he is going to get electrocuted!” I also said that he was a musician. The chaplain said, “Send him around.” It turns out that this Jewish kid knew all of the hymns of any church you wanted to name by heart. He was good and the chaplain snapped him up and saved his life. We had some real electromagnetic hazards there. We went on overseas and I put a lot of equipment in all across North Africa into Turkey and so on. The equipment we had in those days was Super Pros and it just racked them up one after the other. We started listening to the Russians when the war was over, and got them annoyed. One other adventure we had at that time that was really not electromagnetic. I guess it’s incompatibility, if you want to call it that.

In Ankara, the British ambassador office one of his staff with a problem. The only thing that kept this man sane, was his ability to listen to BBC in the evening. That was his lifeline. He had a Marconi receiver, and they had in those days a form of electrolytic capacitor that actually had liquid in it, and this thing apparently got shorted through. He kept listening to BBC through this hum and finally one day he had an old-fashioned steam boiler explosion where this can exploded, broke the tubes, and scattered corrosive liquid all over the whole thing. We were busy installing those Hammerlund receivers. We put them on the guise that we were helping the Turkish government upgrade its airports for both the civilian and the military. The real reason we were putting them in was to listen in on Soviet Union and they knew it. This British officer looks brought in his poor receiver and he says, “Can you Yanks do anything for it?” I was chief of the radio section, and I said, “No, that thing is beyond repair.” And the lieutenant says, “Give him one of the Super Pros.” It was pretty big, the size of a good-sized oven, and it had a power supply that contained a lot of iron. So we sent this poor guy off with his toy. After he was gone I went back to the office and said, “OK, sir. How are you going to explain this one?” He looks me straight in the eye and says, “Lost in combat.” By that time the war was on the other side of the world!