IEEE
You are not logged in, please sign in to edit > Log in / create account  

Milestones:Directive Short Wave Antenna, 1924

From GHN

(Difference between revisions)
Jump to: navigation, search
(5 intermediate revisions by 3 users not shown)
Line 1: Line 1:
 
== Directive Short Wave Antenna, 1924  ==
 
== Directive Short Wave Antenna, 1924  ==
  
Miyagi, Japan Dedicated June 1995 - IEEE Tokyo Section  [[Image:Yagi Directive shortwave antenna.jpg|thumb]]  
+
Miyagi, Japan Dedicated June 1995 - [[IEEE Tokyo Section History|IEEE Tokyo Section]]  
  
''In these laboratories, beginning in 1924, Professor Hidetsugu Yagi and his assistant, Shintaro Uda, designed and constructed a sensitive and highly-directional antenna using closely-coupled parasitic elements. The antenna, which is effective in the higher-frequency ranges, has been important for radar, television, and [[Amateur Radio|amateur radio]].''
+
[[Image:Yagi Directive shortwave antenna.jpg|thumb]]  
  
The antenna system, using a driven element with closely coupled parasitics (usually a reflector and one or more directors) for short-wave work, was first described by S. Uda, a professor at Tohuku University in Japan, in 1926, in the IEEJ (Japan). A colleague, Professor H. Yagi, collaborated in the developmental work and published the more widely read English version in the June 1928 IRE Proceedings. The antenna, often termed a Yagi, should have a credit to both inventors.  
+
''In these laboratories, beginning in 1924, Professor Hidetsugu Yagi and his assistant, [[Shintaro Uda|Shintaro Uda]], designed and constructed a sensitive and highly-directional antenna using closely-coupled parasitic elements. The antenna, which is effective in the higher-frequency ranges, has been important for radar, television, and [[Amateur Radio|amateur radio]].''
 +
 
 +
'''The plaque can be viewed at Tohoku University, outside near the statue of Dr. H. Yagi; Aoba-cho, Sendai-shi, Miyagi-ken, 980, Japan.'''
 +
 
 +
The antenna system, using a driven element with closely coupled parasitics (usually a reflector and one or more directors) for short-wave work, was first described by S. Uda, a professor at Tohuku University in Japan, in 1926, in the IEEJ (Japan). A colleague, Professor H. Yagi, collaborated in the developmental work and published the more widely read English version in the June 1928 IRE Proceedings. The antenna, often termed a [[Yagi Antenna|Yagi]], should have a credit to both inventors.  
  
 
The invention came at a crucial time in the development of short-wave engineering when new tubes permitted higher frequency and more stable outputs. Applications such as [[Amateur Radio|amateur radio]], point-to-point communication, VHF Radar and television receiving were natural outlets for the Yagi-Uda antenna system.  
 
The invention came at a crucial time in the development of short-wave engineering when new tubes permitted higher frequency and more stable outputs. Applications such as [[Amateur Radio|amateur radio]], point-to-point communication, VHF Radar and television receiving were natural outlets for the Yagi-Uda antenna system.  
Line 15: Line 19:
 
The Yagi-Uda antenna has a narrow frequency range as a consequence of its ability to provide power gain in a specific direction. Also there is a power limitation which prevents many kilowatts from being radiated without causing corona effects on the system. Hence the antenna is not suitable for short wave high power broadcasting transmission (but it can be used for reception.)  
 
The Yagi-Uda antenna has a narrow frequency range as a consequence of its ability to provide power gain in a specific direction. Also there is a power limitation which prevents many kilowatts from being radiated without causing corona effects on the system. Hence the antenna is not suitable for short wave high power broadcasting transmission (but it can be used for reception.)  
  
A United States patent was issued to Yagi in 1932 and assigned to RCA. Such antennas were available for television by the late 1930´s, but were more widespread for receiving purposes in the 1940´s and 1950´s.  
+
A United States patent was issued to Yagi in 1932 and assigned to [[RCA (Radio Corporation of America)|RCA]]. Such antennas were available for television by the late 1930´s, but were more widespread for receiving purposes in the 1940´s and 1950´s.  
  
 
Applications would include any system usually less than 1000 Mhz - in the HF and SHF portions of the spectrum where antenna gain and directionality are factors. Avionic systems and VHF radar were very suitable technical areas.  
 
Applications would include any system usually less than 1000 Mhz - in the HF and SHF portions of the spectrum where antenna gain and directionality are factors. Avionic systems and VHF radar were very suitable technical areas.  
  
Elliot Sivowitch<br>Smithsonian Institution<br>
+
Elliot Sivowitch<br>Smithsonian Institution
  
<googlemap controls="small" height="250" width="300" zoom="10" lon="140.859116" lat="38.271629" version="0.9">
+
<div class="header"><span class="head1">INNOVATION</span><span class="head2">  MAP</span></div>
 +
<googlemap version="0.9" lat="38.271629" lon="140.859116" zoom="10" width="300" height="250" controls="small">
 
38.271629, 140.859116,
 
38.271629, 140.859116,
 
Directive Short Wave Antenna, 1924  
 
Directive Short Wave Antenna, 1924  
 
The laboratories have been remodeled, so the plaque is on a monument in the center of Katahira Campus, Tohoku University, Sendai, Japan  
 
The laboratories have been remodeled, so the plaque is on a monument in the center of Katahira Campus, Tohoku University, Sendai, Japan  
</googlemap>  
+
</googlemap>
  
[[Category:Communications|{{PAGENAME}}]] [[Category:Radio_communication|{{PAGENAME}}]] [[Category:Radio_frequency|{{PAGENAME}}]]
+
[[Category:Fields,_waves_&_electromagnetics|{{PAGENAME}}]]
 +
[[Category:Antennas|{{PAGENAME}}]]
 +
[[Category:Directive_antennas|{{PAGENAME}}]]
 +
[[Category:News|{{PAGENAME}}]]

Revision as of 20:47, 26 November 2013

Directive Short Wave Antenna, 1924

Miyagi, Japan Dedicated June 1995 - IEEE Tokyo Section

In these laboratories, beginning in 1924, Professor Hidetsugu Yagi and his assistant, Shintaro Uda, designed and constructed a sensitive and highly-directional antenna using closely-coupled parasitic elements. The antenna, which is effective in the higher-frequency ranges, has been important for radar, television, and amateur radio.

The plaque can be viewed at Tohoku University, outside near the statue of Dr. H. Yagi; Aoba-cho, Sendai-shi, Miyagi-ken, 980, Japan.

The antenna system, using a driven element with closely coupled parasitics (usually a reflector and one or more directors) for short-wave work, was first described by S. Uda, a professor at Tohuku University in Japan, in 1926, in the IEEJ (Japan). A colleague, Professor H. Yagi, collaborated in the developmental work and published the more widely read English version in the June 1928 IRE Proceedings. The antenna, often termed a Yagi, should have a credit to both inventors.

The invention came at a crucial time in the development of short-wave engineering when new tubes permitted higher frequency and more stable outputs. Applications such as amateur radio, point-to-point communication, VHF Radar and television receiving were natural outlets for the Yagi-Uda antenna system.

In the basic technical operation a driven element, usually ½ l is connected to the transmitter through coax cable. In close proximity to the driver, but not physically connected to it is a reflector, usually more than ½ l and one or more directors (usually less than ½ l ). The E.M. wave interaction between the elements of the "beam" antenna acts to re-radiate the signal in a specific direction (i.e. in the direction of the "directors") and with a significant "power gain" - a good beam figure is in the area of 7 db. gain.

In reception the reverse occurs, and a weak signal is acted upon by the director network to boost the signal up to 7 db.

The Yagi-Uda antenna has a narrow frequency range as a consequence of its ability to provide power gain in a specific direction. Also there is a power limitation which prevents many kilowatts from being radiated without causing corona effects on the system. Hence the antenna is not suitable for short wave high power broadcasting transmission (but it can be used for reception.)

A United States patent was issued to Yagi in 1932 and assigned to RCA. Such antennas were available for television by the late 1930´s, but were more widespread for receiving purposes in the 1940´s and 1950´s.

Applications would include any system usually less than 1000 Mhz - in the HF and SHF portions of the spectrum where antenna gain and directionality are factors. Avionic systems and VHF radar were very suitable technical areas.

Elliot Sivowitch
Smithsonian Institution

INNOVATION MAP