Milestones:First Breaking of Enigma Code by the Team of Polish Cipher Bureau, 1932-1939 and Milestones:Loran, 1940 - 1946: Difference between pages

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Loran, 1940-1946

The rapid development of Loran -- long range navigation -- under wartime conditions at MIT’s Radiation Lab was not only a significant engineering feat but also transformed navigation, providing the world’s first near-real-time positioning information. Beginning in June 1942, the United States Coast Guard helped develop, install and operate Loran until 2010.

The plaque may be viewed attached to MIT Building N42, wall mounted outdoors alongside other plaques at 211 Massachusetts Avenue. The plaque is visible to pedestrians walking on this public sidewalk.

In October 1940, MIT was chosen for the site of an independent laboratory that would be staffed by civilian and academic scientists from every discipline. Fourteen months before the U.S. entered World War II, MIT formed, under government contract, a newly Radiation Laboratory began its investigation of radio navigation and radar. The radio navigation division was housed separately from the radar group but was always referred to as Radiation Laboratory. The staff was housed in their own building in Cambridge. On 31 December 1945, the Radiation Laboratory was formally closed and staff members returned to their careers.

Loran (long-range navigation) was a large engineered system, developed in the 1940s and successfully deployed in the Second World War. Now, over sixty years later, every mariner in the world have used or know loran. By 1946, loran was used by thousands of navigators over three-tenths of the surface of the earth. Loran is a hyperbolic system of navigation based on pulse-modulated synchronized signals.

Military personnel, scientists, engineers, fabricators, technicians, radio operators, all had important roles in building and deploying loran. Plans, scientific research, tests, and the early loran transmitters were fabricated in the shop in Cambridge. Radio technicians and navigators were trained here in Boston. After attending Loran School, they would return to their assigned transmitter station, ship, or aircraft. Navigation Division and Key Individuals:

At its peak level of staffing, there were about 60 people in the radio navigation: scientists, academics, engineers, and technicians. Their job included research, design, plan, engineer, and develop a whole new system of navigation called loran – long-range navigation system. For a short period of time, the original staff had to operate and man the first two transmitting stations. Melville Eastman managed the division from 1941 to 1943. Eastman, CEO and founder of General Radio Corporation of Cambridge, was on leave from his company during that period. Donald G Fink replaced Eastman on March 1943. Donald G Fink worked at the MIT Radiation Laboratory and traveled overseas installing loran sites. Fink had a long association with the Institute of Radio Engineers and was elected president of the IRE in 1958.

The chief researcher and scientist was JA (Jack) Pierce, a scientist fellow from Harvard University, Cambridge. He joined the team in 1941. Later in his career, Pierce would receive the Medal For Engineering Excellence for the design, teaching and advocacy of radio propagation, navigation and timing. His work led to the development of Loran, Loran C and other systems.

Monitoring the project and coordinating with superiors in Washington DC was Lawrence M. Harding, a senior officer in the United States Coast Guard (USCG). In 1942 he was transferred to Cambridge Massachusetts to coordinate with US Navy and government agencies. It was he who came up with the name LORAN derived from long-range navigation. Harding played an important role in surveys, logistics, equipment transportation, and building loran stations along the Atlantic coasts. By 1943, Harding and the Coast Guards were able get some twenty-five loran transmitter stations erected and running in the Aleutian Islands and the Pacific.

Loran is a hyperbolic system of navigation by which difference in distance from two points on shore is determined by measurement of the time interval between receptions of pulse- modulated synchronized signals from transmitters at the two points. Both ground waves and sky waves can be used to provide coverage over an extensive area with few stations, depending on design frequencies. An important advantage of loran at the time of its development during World War 2 was that a ship could use loran without breaking radio silence. Loran transmitting stations work in pairs. Synchronization is achieved by letting the signals of the master station, control those of the slave station. To help overcome the disadvantage of requiring two transmitting stations for a single family of hyperbolic lines of positions, loran forms a chain of stations, so that each station except the end ones operate with the station on either side to form an intersecting lattice of position lines. To find his way, a loran navigator on a ship had to be trained, have a loran receiver-indicator, and a set of loran nautical charts or loran tables. Standard loran was initially developed primarily for navigation over water, but was also used for air-borne navigation.

Today's loran operates on one of several frequencies between1700 and 2000 kHz. It enjoys propagation characteristics determined primarily by soil conductivity and ionosphere conditions. Both ground wave and sky waves can be used to provide coverage over an extensive area with few stations. Usually, stations of a pair are located 200 to 400 miles or more. At one time, 1000 to 1400 miles apart separated several station pairs. Transmitters now in use radiate about 100kw and give a ground-wave range over seawater of about 700 nautical miles in the daytime. The daytime range over land is seldom more than 250 miles even for high-flying aircraft and is scarcely 100 miles at the surface of the earth. At night the ground-wave range oversea water is reduced to about 500 miles by the increase in atmospheric noise, but sky waves, which are almost completely absorbed by day, become effective and increase the reliable night range to about 1400 miles. Generally, a number of stations are physically located so as to form a chain, with all but the end station in the group being double pulsing. In most parts of the world, signals can be received from at least two pairs of stations making it possible for a mariner to determine a fix using loran alone.

Loran was developed and placed in service under trying war time conditions:

1. Loran stations were often in remote isolated area, making field construction difficult.

2. Cooperation among different countries was required: Canada, Denmark, and Britain, for example.

3. High reliability requirements: In his article, Pierce describes the features taken into account during the design because of high requirements for continuous service. He states that the transmitters worked satisfactorily within specified limits “99 percent of the times”. That's pretty impressive for first generation equipment, considering that loran transmitters are synchronized and operate in pairs. Because the time at which the slave pulse reaches the master station is known, the master station continuously monitors the slave pulse. If a discrepancy is detected, the master alerts the slave station. Either station can initiate a trouble alarm to navigators warning of a potential problem.

To simplify maintenance, all units were in duplicate with provisions for quick interchange of operating and stand-by units. Overlapping coverage, multiple timers, were provided. Shielded rooms were used to protect timers from interferences.

4. Living at remote isolated loran stations: Loran stations were often isolated, remote, dreary places. One website explains as follows:

"The crews of loran stations varied somewhat in size, depending on their locations. They have averaged about fifteen men. As the stations had to be entirely self-sufficient, they had cooks, hospital corpsmen, in addition to the electronic technicians who operated and maintained the transmitters. Each station was commanded by a commissioned officer, usually a lieutenant, with a chief petty officer as second in command. Prospective commanding officers were given a short training course in loran and administration before assignment. Many young men dreaded loran duty because of the isolation, but after it is over, nearly all of them felt it had been well worthwhile. At isolated stations, tours of duty were for one year. The great majority of loran stations were supplied with fuel, bulky spare parts, and large staple items by a Coast Guard supply ship, which called once or twice a year. Unless they were located near a large community, loran stations received mail; personnel, fresh stores, and emergency spare parts by Coast Guard airplane. Most stations had their own airstrip."

5. Training operators and navigators: A great number of radio operators and technicians from the US and other countries had to be trained on how to operate the new navigation transmitters. Additionally, navigators aboard ships and aircrafts had to learn a whole new way of doing things to find their fix.

[edit] What features or characteristics set this work apart from similar achievements?

Loran was an entirely new system of radio navigation. Its unique achievement was the speed in which loran was developed and pressed into service during the war. By 1946, loran was used by thousands of navigators over three-tenths of the surface of the earth.

By 1946, the extent of loran coverage available to navigators is illustrated in the accompanying figure. The North Atlantic Chain was given priority to allow ship convoys to find their way across treacherous waters. During wartime, Loran had the advantage of allowing ships to maintain radio silence.

In The North Atlantic:

MIT Radiation Laboratory’s loran personnel was heavily involved with research and development of the North Atlantic Chain. The first Loran-A pair was on the air permanently by June 1942 (Montauk Point, NY, and Fenwick Is, Del.), and by October there were additional stations along the Canadian east coast. The system became operational in early 1943, and late that year stations were established in Greenland, Iceland, the Faeroes and the Hebrides to complete the North Atlantic cover. Loran stations were manned by the United States Coast Guard (USCG), Royal Canadian Navy (RCN), and the Royal Navy (RN). At the request of the RAF, another station was put into the Shetlands to cover Norway, and loran was eventually used by over 450 aircraft of Coastal Command.

By 1944, the North Atlantic Chain consisted of the following loran stations. The name of the organization operating the station is also identified. Fenwick Island, Delaware, DE - USCG Mantauk Point, Long Island NY - USCG Baccaro, Nova Scotia, Canada - RCN Deming, Nova Scotia, Canada - RCN Bona Vista, Newfoundland - USCG Bath Harbor, Labrador - USCG Frederiks, Greenland - USCG Vik Island - RN Skuvanes Head, Faeroe Island - RN Mangersta, Hebribes - RN Sankaty, Nantucket, MA (monitoring station) - USCG

In the Aleutian Island and the Pacific Ocean:

In the summer of 1943, the USCG completed the first independent installation of loran transmitting stations in the Aleutian Island. The equipment in this case had been quickly fabricated in the shop in Cambridge, as Naval procurement had not yet come into effect. The Coast Guards continued the work and installed twenty-five stations in the Pacific, climaxing its efforts with stations at Jima and Okinawa, which were erected closely on the heels of the invading forces. Of special significance in the Pacific warfare were stations in the Marianas, which provided very effective guidance for the 20th Air Force in its bombing of Japan.

Loran made its greatest direct contribution to winning the war because distances in the Pacific Ocean are enormous. As American forces moved westward, airfields were built on many of the small islands. The limited range of many World War II aircraft demanded that they frequently land and refuel. Loran provided the easy-to-use, accurate navigational system to locate airfields and land for refueling.

Overall Achievement:

At the end of the war, some seventy loran-transmitting stations were in service providing nighttime service over 60 million square miles or three tenths of the earth’s surface. Pierce, in his article, reported that by 1946, 75,000 ship-borne and air-borne navigator’s receivers had been delivered by the various American manufactures. He also reports that the Hydrographic Office, which had been preparing the required loran charts for nautical navigation, had shipped two-and-a-quarter million charts to various operating agencies.

References Used:

1. JA Pierce, "An Introduction to Loran", Proceeding of the IRE, 1946. Reprinted by IEEE AES Magazine 1990 (see attached).
2. Bowditch, American Practical Navigator. U.S. Navy Hydrographic Office, 1958 pp. 333 – 343.
3. The Coast Guard at War: IV LORAN VOLUME II.

Prepared in the Historical Section Public Information Division U.S. Coast Guard Headquarters in 1 August 1946:
http://www.uscg.mil/History/STATIONS/loran_volume_2.asp
http://www.uscg.mil/history/stations/LORAN_Section_2.asp
http://www.uscg.mil/history/stations/LORAN_Volume_1_Index.asp

4. Other Websites:
http://www.loran-history.info/
http:/ www.jproc.ca/hyperbolic/loran_a.html
http://en.wikipedia.org/wiki/LORAN

To Probe Further:

Willoughy, Malcolm Francis; The Story of LORAN in the U.S. Coast Guard in World War II, Arno Pro, 1980.

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-{{MilestoneLayout|citation=Polish Cipher Bureau mathematicians Marian Rejewski, Jerzy Różycki and Henryk Zygalski  broke the German Enigma cipher machine codes.  Working with engineers from the AVA Radio Manufacturing Company, they built the ‘bomba’ – the first cryptanalytic machine to break Enigma codes. Their work was a foundation of British code breaking efforts which, with later American assistance, helped end World War II.|gps=ul. Śniadeckich 8,  00-956 Warszawa (Warsaw), Poland
+''Loran, 1940-1946''
-GPS (latitude, longitude) 52.2213787&nbsp;; 21.0146535|plaque=The plaque is at the front entrance of the Institute's building facing the Sniadeckich Street|secured=The plaque site is publicly accessible at one of the busy streets of Warsaw downtown area, with high concentration of academics and tourists. [http://www.chron.com/news/world/article/World-engineers-honor-Polish-Enigma-code-breakers-5669347.php#photo-6685492 Click here for an article with photographs of the plaque monument]|significance=IEEE Milestone Description
-During the 1930s, a trio of Polish mathematicians Marian Rejewski (1905 – 1980), Henryk Zygalski (1907 – 1978),
-and Jerzy Różycki (1909 – 1942) solved the German Enigma cipher machine and broke Enigma messages.
-Working with engineers from AVA Radio Manufacturing Company they built the bomba – the first cryptanalytic
-machine designed to attack Enigma and one of many cryptanalytic machines to be built by Allied codebreakers.
-Enigma is an electrically wired rotor machine; a sequence of ciphers is generated by the motion of rotors in the
-machine.  It is one of several cipher machines that were developed for military or for commercial use during or
-just after World War I.
-German Arthur Scherbius invented Enigma; he patented a rotor machine in 1918.
+''The rapid development of Loran -- long range navigation -- under wartime conditions at MIT’s Radiation Lab was not only a significant engineering feat but also transformed navigation, providing the world’s first near-real-time positioning information. Beginning in June 1942, the United States Coast Guard helped develop, install and operate Loran until 2010.''
-An American, Edward Hebern, had designed a rotor cipher machine in 1917, and the Dutch inventor
-Hugo Koch and the Swedish inventor Arvid Damm designed machines that were patented in 1919.
-It is likely that both Scherbius’ and Koch’s designs resulted from a rotor machine developed in 1915
-by two Dutch military officers.
-The weaknesses of their World War I codes and ciphers prompted the German military to adopt a cipher machine.
-The Reichsmarine began using Enigma in 1926, and the Reichswehr began using it in 1928.
+<br>
-The Polish Cipher Bureau had many successes during the Polish-Soviet War (1919 – 1921), and in the 1920s the
+The plaque may be viewed attached to MIT Building N42, wall mounted outdoors alongside other plaques at 211 Massachusetts Avenue. The plaque is visible to pedestrians walking on this public sidewalk. <br>
-Cipher Bureau monitored radio signals resulting from German military exercises.  In 1928 the Poles were
-confronted by messages that – because of the randomness of letters in the messages – were thought to
-be generated by a machine cipher.
-That same year the Cipher Bureau began a cryptology course for mathematics students at Poznań University.
-Rejewski, Zygalski, and Różycki participated in that course.  They began working for the Cipher Bureau
-in Poznań but moved to Warsaw, and Rejewski began his attack on Enigma in September 1932.
+<br>
-Although the Cipher Bureau was aware of the operation of a commercial Enigma, the rotors of the German
+In October 1940, MIT was chosen for the site of an independent laboratory that would be staffed by civilian and academic scientists from every discipline. Fourteen months before the U.S. entered World War II, MIT formed, under government contract, a newly Radiation Laboratory began its investigation of radio navigation and radar. The radio navigation division was housed separately from the radar group but was always referred to as Radiation Laboratory. The staff was housed in their own building in Cambridge. On 31 December 1945, the Radiation Laboratory was formally closed and staff members returned to their careers.
-military Enigma had different wiring than the commercial version, and the German military had complicated
-the machine by adding a plugboard, which further greatly scrambled the letters.  By the end of 1932,
-Rejewski had determined the wiring of the rotors of the military version of Enigma.  In 1932, Rejewski
-had received from the French two German manuals that described the operation of military Enigma.
-He had managed to write a system of equations that modeled the permutations of the six indicators
-(which were used by the sending operator to transmit the message setting to the receiving operator)
-at the beginning of Enigma messages.  In December 1932, Rejewski received from the French the setting
-sheets for September and October.  This information allowed Rejewski to substitute for some of the
-unknowns in his system of equations and solve for the wiring of the rotors.
-The Cipher Bureau arranged with AVA Radio Manufacturing Company to produce Enigma “doubles.”
-Doubles were produced in 1934.
-AVA Company had been established by Edward Fokczyński and
+Loran (long-range navigation) was a large engineered system, developed in the 1940s and successfully deployed in the Second World War. Now, over sixty years later, every mariner in the world have used or know loran. By 1946, loran was used by thousands of navigators over three-tenths of the surface of the earth. Loran is a hyperbolic system of navigation based on pulse-modulated synchronized signals.
-Antoni Palluth to design and produce telecommunications equipment for the Polish army.
-They were soon joined by the brothers Ludomir and Leonard Danilewicz, who had graduated from
-Warsaw University of Technology.
-In order to break Enigma messages, it was necessary to determine the machine settings.  The Polish codebreakers
-developed several techniques to determine settings.  For example, Różycki developed the “clock method,”
-and Zygalski developed a set of perforated sheets.  Two other methods resulted in the production of
-codebreaking machines – one machine to produce a catalog of settings and their “characteristics” and
-another to determine the rotor settings.
+Military personnel, scientists, engineers, fabricators, technicians, radio operators, all had important roles in building and deploying loran. Plans, scientific research, tests, and the early loran transmitters were fabricated in the shop in Cambridge. Radio technicians and navigators were trained here in Boston. After attending Loran School, they would return to their assigned transmitter station, ship, or aircraft. Navigation Division and Key Individuals:
-In 1934, Rejewski was able to exploit patterns, which he called characteristics, produced by the six-letter
+At its peak level of staffing, there were about 60 people in the radio navigation: scientists, academics, engineers, and technicians. Their job included research, design, plan, engineer, and develop a whole new system of navigation called loran – long-range navigation system. For a short period of time, the original staff had to operate and man the first two transmitting stations. Melville Eastman managed the division from 1941 to 1943. Eastman, CEO and founder of General Radio Corporation of Cambridge, was on leave from his company during that period. Donald G Fink replaced Eastman on March 1943. Donald G Fink worked at the MIT Radiation Laboratory and traveled overseas installing loran sites. Fink had a long association with the Institute of Radio Engineers and was elected president of the IRE in 1958.
-indicators at the beginning of Enigma messages.  Rejewski designed a machine called the cyclometer to
-catalog the characteristics of all 105,456 rotor settings.  Again, the AVA Radio Manufacturing Company
-produced the machine.  It took the codebreakers approximately a year to prepare the catalog.
-Unfortunately not long after its completion, the Germans changed Enigma’s reflecting rotor, and
-the catalog had to be redone. This method was rendered useless when the indicator procedure
-changed in September 1938.
-However, Rejewski found patterns in the new indicators.  Working with the engineers at AVA, one of
-the most famous codebreaking machines – the bomba – was produced.  The six bomby (plural in
-Polish for “bomba”) searched through all 105,456 rotor settings for those that exhibited patterns
-that could be determined from the indicators after a sufficient number of messages were intercepted.  (Note: The reason that it is written both “bomba” and “bombę” is the declension endings. “Bomba” is for “who” or “what” and “bombę” is for “whom, what for?”)
-Usually only a small number of settings produced the patterns, and each of those settings was tried
-to determine the one that was correct.  Because there were three rotors and three positions for rotors
-in Enigma, there were six possible rotor orders; therefore, six bomby were produced.  In December
-, the Germans introduced two new rotors.  Then there were sixty possible ways to select three
-rotors from the set and place them in Enigma; sixty bomby would have been needed, and the Cipher
-Bureau could not afford to build them.  After the change, the Cipher Bureau could break few Enigma
-messages.
+The chief researcher and scientist was JA (Jack) Pierce, a scientist fellow from Harvard University, Cambridge. He joined the team in 1941. Later in his career, Pierce would receive the Medal For Engineering Excellence for the design, teaching and advocacy of radio propagation, navigation and timing. His work led to the development of Loran, Loran C and other systems.
-In July 1939, as war with Germany loomed over Poland, the Polish codebreakers met just outside Warsaw
+Monitoring the project and coordinating with superiors in Washington DC was Lawrence M. Harding, a senior officer in the United States Coast Guard (USCG). In 1942 he was transferred to Cambridge Massachusetts to coordinate with US Navy and government agencies. It was he who came up with the name LORAN derived from long-range navigation. Harding played an important role in surveys, logistics, equipment transportation, and building loran stations along the Atlantic coasts. By 1943, Harding and the Coast Guards were able get some twenty-five loran transmitter stations erected and running in the Aleutian Islands and the Pacific.
-with British and French codebreakers.  At this meeting the Poles described their achievements against Enigma.
-As a result of the meeting, the British and the French each received one of the Enigma doubles and information
-on the methods used by the Poles to solve daily keys.
-On September 1, 1939, Germany attacked Poland, and British codebreakers at Bletchley Park continued
-the attack on Enigma.  British mathematicians such as Alan Turing and Gordon Welchman and engineers
-such as Harold “Doc” Keen and Thomas “Tommy” Flowers developed cryptanalytic machines to attack
-Enigma and other German ciphers. One of the machines to attack Enigma was the Turing-Welchman
-bombe.  (IEEE Milestone, Bletchley Park, 1939 – 1945)  Both the British bombe and the Polish bomba
-searched through all possible Enigma rotor settings for settings that produced patterns that had been
-noticed by the codebreakers.  The British bombe searched for patterns in Enigma messages, and the
-Polish bomba searched for patterns in Enigma indicators.
+Loran is a hyperbolic system of navigation by which difference in distance from two points on shore is determined by measurement of the time interval between receptions of pulse- modulated synchronized signals from transmitters at the two points. Both ground waves and sky waves can be used to provide coverage over an extensive area with few stations, depending on design frequencies. An important advantage of loran at the time of its development during World War 2 was that a ship could use loran without breaking radio silence. Loran transmitting stations work in pairs. Synchronization is achieved by letting the signals of the master station, control those of the slave station. To help overcome the disadvantage of requiring two transmitting stations for a single family of hyperbolic lines of positions, loran forms a chain of stations, so that each station except the end ones operate with the station on either side to form an intersecting lattice of position lines. To find his way, a loran navigator on a ship had to be trained, have a loran receiver-indicator, and a set of loran nautical charts or loran tables. Standard loran was initially developed primarily for navigation over water, but was also used for air-borne navigation.
-After the United States entered the war, US Navy mathematicians at Naval Communications in
+Today's loran operates on one of several frequencies between1700 and 2000 kHz. It enjoys propagation characteristics determined primarily by soil conductivity and ionosphere conditions. Both ground wave and sky waves can be used to provide coverage over an extensive area with few stations. Usually, stations of a pair are located 200 to 400 miles or more. At one time, 1000 to 1400 miles apart separated several station pairs. Transmitters now in use radiate about 100kw and give a ground-wave range over seawater of about 700 nautical miles in the daytime. The daytime range over land is seldom more than 250 miles even for high-flying aircraft and is scarcely 100 miles at the surface of the earth. At night the ground-wave range oversea water is reduced to about 500 miles by the increase in atmospheric noise, but sky waves, which are almost completely absorbed by day, become effective and increase the reliable night range to about 1400 miles. Generally, a number of stations are physically located so as to form a chain, with all but the end station in the group being double pulsing. In most parts of the world, signals can be received from at least two pairs of stations making it possible for a mariner to determine a fix using loran alone.
-Washington, DC, designed cryptanalytic machines to attack Japanese ciphers and machines to
-assist the British with the attack on naval Enigma.  These codebreaking machines were engineered
-by Joseph Desch and other engineers at the Naval Computing Machine Laboratory located at National
-Cash Register Company in Dayton, OH.  One of the machines to attack naval Enigma was the US Navy
-cryptologic bombe.  (IEEE Milestone, Naval Computing Machine Laboratory, 1942 – 1945)  The US
-Navy bombe – like the British bombe – searched for patterns in Enigma messages.
-At the beginning of the German attack on Poland, Rejewski, Zygalski, and Różycki fled Warsaw,
-and they arrived in Paris in late September.  By the end of October they were again working on
-German ciphers – now at Command Post (P.C.) Bruno at Gretz-Armainvillers near Paris.  The Poles
-and the British exchanged Enigma keys.  In January 1940, Alan Turing visited the Polish codebreakers
-in France.  Turing brought the Poles the British version of the Zygalski sheets, and the Poles provided
-Turing with corrected information on the wiring of Enigma rotors IV and V.
-Palluth and Fokczyński had also fled to France. Palluth maintained the team’s radio contact with London
-and later with Algiers and was involved with monitoring German radio signals.  Fokczynski repaired
-radio and cipher equipment.
-Following the German attack on France in May 1940, Rejewski, Zygalski, and Różycki evacuated to
+Loran was developed and placed in service under trying war time conditions:
-North Africa.  By October they had returned to Vichy France and continued attacking German ciphers.
-They were located near Uzès at P.C. Cadix.  Until Germany took control of South France, the Polish
-codebreakers traveled to and from North Africa.  On January 9, 1942, on a trip back to France after
-a three-month assignment in the cipher section in Algiers, Różycki died when the ship on which he
-was traveling sank.  In November 1942, after Operation Torch, the Allied attack on North Africa,
-Germany occupied free France.  Rejewski and Zygalski undertook a harrowing crossing into Spain,
-which included their being detained in Spanish prisons.  After their release, they traveled to Portugal
-and then to Gibraltar from where they flew to Britain.
-Palluth and Fokczyński were both captured during the crossing into Spain.  They both died in the
-Sachsenhausen camp – Palluth during an Allied bombing raid and Fokczyński due to illness.
-Rejewski and Zygalski arrived in Great Britain in August 1943 and served with the Communications
-Battalion of the Polish Armed Forces Commander-in-Chief’s General Staff.  Both served in the German
-section.  Their work until the end of the war was breaking manual SS and SD ciphers.
-After the war, Zygalski remained in England and worked at the Polish University.  He died in 1978 in Liss,
+. Loran stations were often in remote isolated area, making field construction difficult.
-near Portsmouth.  When the war ended, Rejewski returned to his home in Bydgoszcz where, despite
-harassment by the Polish security services, he worked for various companies until his retirement
-because of poor health in 1966.  He moved to Warsaw in 1969 and died there of a heart attack in 1980.
-IEEE Poland Section is indebted to Dr. Chris Christensen and Mr. Ralph Erskine for their editorial support and useful comments added to this manuscript, especially concerning the existing related IEEE Milestones (1939-45 Bletchley Park, and 1942-45 Naval Computing Machine Laboratory)|features=On September 1, 1939, Germany attacked Poland, and British codebreakers at Bletchley Park continued the attack on Enigma.  British mathematicians such as Alan Turing and Gordon Welchman and engineers such as Harold “Doc” Keen and Thomas “Tommy” Flowers developed cryptanalytic machines to attack Enigma and other German ciphers. One of the machines to attack Enigma was the Turing-Welchman bombe.  (IEEE Milestone, Bletchley Park, 1939 – 1945)  Both the British bombe and the Polish bomba searched through all possible Enigma rotor settings for settings that produced patterns that had been noticed by the codebreakers.  The British bombe searched for patterns in Enigma messages, and the Polish bomba searched for patterns in Enigma indicators.
+. Cooperation among different countries was required: Canada, Denmark, and Britain, for example.
-After the United States entered the war, US Navy mathematicians at Naval Communications in Washington, DC, designed cryptanalytic machines to attack Japanese ciphers and machines to assist the British with the attack on naval Enigma.  These codebreaking machines were engineered by Joseph Desch and other engineers at the Naval Computing Machine Laboratory located at National Cash Register Company in Dayton, OH.  One of the machines to attack naval Enigma was the US Navy cryptologic bombe.  (IEEE Milestone, Naval Computing Machine Laboratory, 1942 – 1945)  The US Navy bombe – like the British bombe – searched for patterns in Enigma messages.|references=The achievements outlined above are covered in more detail in the following publications:
+. High reliability requirements: In his article, Pierce describes the features taken into account during the design because of high requirements for continuous service. He states that the transmitters worked satisfactorily within specified limits “99 percent of the times”. That's pretty impressive for first generation equipment, considering that loran transmitters are synchronized and operate in pairs. Because the time at which the slave pulse reaches the master station is known, the master station continuously monitors the slave pulse. If a discrepancy is detected, the master alerts the slave station. Either station can initiate a trouble alarm to navigators warning of a potential problem.
-[1]	Frank Carter, “The First Breaking of Enigma: Some of the Pioneering Techniques Developed by the Polish Cipher Bureau,” Report No 2, Bletchley Park Trust, 2008.
-[2]	Jennifer Wilcox, “Solving the Enigma: History of the Cryptanalytic Bombe,” Center for Cryptologic History, National Security Agency, 2006. http://www.nsa.gov/about/_files/cryptologic_heritage/publications/wwii/solving_enigma.pdf
+To simplify maintenance, all units were in duplicate with provisions for quick interchange of operating and stand-by units. Overlapping coverage, multiple timers, were provided. Shielded rooms were used to protect timers from interferences.
-[3]	Chris Christensen,”Polish Mathematicians Finding Patterns in Enigma Messages,” Mathematics Magazine, 80(4), October 2007, pp. 247-273.
-[4]	F. H. Hinsley, et al., British Intelligence in the Second World War: Its Influence on Strategy and Operations (book). 3(2), Appendix 30.
+. Living at remote isolated loran stations: Loran stations were often isolated, remote, dreary places. One website explains as follows:
-[5]	Andrew Hodges, Alan Turing: The Enigma, Simon & Schuster, 1983 (book).  This is also available in a Polish translation: Andrew Hodges, Enigma. Życie i śmierć Alana Turinga, Prószyński i S-ka, Warsaw, 2002.
-[6]	Brian Johnson, The Secret War, Methuen Inc, 1978 (book).  This is also available in a Polish translation: Brian Johnson, Sekrety Drugiej Wojny Światowej. Wojna Mózgów, Zysk i S-ka, Warsaw, 1997.
+"The crews of loran stations varied somewhat in size, depending on their locations. They have averaged about fifteen men. As the stations had to be entirely self-sufficient, they had cooks, hospital corpsmen, in addition to the electronic technicians who operated and maintained the transmitters. Each station was commanded by a commissioned officer, usually a lieutenant, with a chief petty officer as second in command. Prospective commanding officers were given a short training course in loran and administration before assignment. Many young men dreaded loran duty because of the isolation, but after it is over, nearly all of them felt it had been well worthwhile. At isolated stations, tours of duty were for one year. The great majority of loran stations were supplied with fuel, bulky spare parts, and large staple items by a Coast Guard supply ship, which called once or twice a year. Unless they were located near a large community, loran stations received mail; personnel, fresh stores, and emergency spare parts by Coast Guard airplane. Most stations had their own airstrip."
-[7]	Władysław Kozaczuk, W kręgu Enigmy, Książka i Wiedza, Warsaw 1986 (book).
-[8]	David Kahn, The Codebreakers: The Story of Secret Writing, Scribner; Revised Edition, 1996 (book).  This is also available in a Polish translation: Łamacze kodów: Historia kryptologii, WNT Warszawa, 2004.
+. Training operators and navigators: A great number of radio operators and technicians from the US and other countries had to be trained on how to operate the new navigation transmitters. Additionally, navigators aboard ships and aircrafts had to learn a whole new way of doing things to find their fix.
-[9]	Marian Rejewski, Memories of My Work at the Cipher Bureau of the General Staff Second Department 1930-45, Adam Mickiewicz University Press, Poznań, Poland, 2011 (book.)  Half of this book is written in Polish, and the other half is a translation into English.
-Websites:
+[edit] What features or characteristics set this work apart from similar achievements? <br><br>Loran was an entirely new system of radio navigation. Its unique achievement was the speed in which loran was developed and pressed into service during the war. By 1946, loran was used by thousands of navigators over three-tenths of the surface of the earth.
-US National Security Agency’s Center for Cryptologic History website:
+[[Image:Loran1.jpg|thumb|right]]
-http://www.nsa.gov/about/cryptologic_heritage/center_crypt_history/publications/wwii.shtml
+By 1946, the extent of loran coverage available to navigators is illustrated in the accompanying figure. The North Atlantic Chain was given priority to allow ship convoys to find their way across treacherous waters. During wartime, Loran had the advantage of allowing ships to maintain radio silence.
-There are many Enigma websites, including Wikipedia’s comprehensive coverage at
-http://en.wikipedia.org/wiki/Cryptanalysis_of_the_Enigma|support=}}
+In The North Atlantic:
+MIT Radiation Laboratory’s loran personnel was heavily involved with research and development of the North Atlantic Chain. The first Loran-A pair was on the air permanently by June 1942 (Montauk Point, NY, and Fenwick Is, Del.), and by October there were additional stations along the Canadian east coast. The system became operational in early 1943, and late that year stations were established in Greenland, Iceland, the Faeroes and the Hebrides to complete the North Atlantic cover. Loran stations were manned by the United States Coast Guard (USCG), Royal Canadian Navy (RCN), and the Royal Navy (RN). At the request of the RAF, another station was put into the Shetlands to cover Norway, and loran was eventually used by over 450 aircraft of Coastal Command.
+By 1944, the North Atlantic Chain consisted of the following loran stations. The name of the organization operating the station is also identified. Fenwick Island, Delaware, DE - USCG Mantauk Point, Long Island NY - USCG Baccaro, Nova Scotia, Canada - RCN Deming, Nova Scotia, Canada - RCN Bona Vista, Newfoundland - USCG Bath Harbor, Labrador - USCG Frederiks, Greenland - USCG Vik Island - RN Skuvanes Head, Faeroe Island - RN Mangersta, Hebribes - RN Sankaty, Nantucket, MA (monitoring station) - USCG
+In the Aleutian Island and the Pacific Ocean:
+In the summer of 1943, the USCG completed the first independent installation of loran transmitting stations in the Aleutian Island. The equipment in this case had been quickly fabricated in the shop in Cambridge, as Naval procurement had not yet come into effect. The Coast Guards continued the work and installed twenty-five stations in the Pacific, climaxing its efforts with stations at Jima and Okinawa, which were erected closely on the heels of the invading forces. Of special significance in the Pacific warfare were stations in the Marianas, which provided very effective guidance for the 20th Air Force in its bombing of Japan.
+Loran made its greatest direct contribution to winning the war because distances in the Pacific Ocean are enormous. As American forces moved westward, airfields were built on many of the small islands. The limited range of many World War II aircraft demanded that they frequently land and refuel. Loran provided the easy-to-use, accurate navigational system to locate airfields and land for refueling.
+Overall Achievement:
+At the end of the war, some seventy loran-transmitting stations were in service providing nighttime service over 60 million square miles or three tenths of the earth’s surface. Pierce, in his article, reported that by 1946, 75,000 ship-borne and air-borne navigator’s receivers had been delivered by the various American manufactures. He also reports that the Hydrographic Office, which had been preparing the required loran charts for nautical navigation, had shipped two-and-a-quarter million charts to various operating agencies.
+<br>
+References Used:
+. JA Pierce, "An Introduction to Loran", Proceeding of the IRE, 1946. Reprinted by IEEE AES Magazine 1990 (see attached).<br>2. Bowditch, American Practical Navigator. U.S. Navy Hydrographic Office, 1958 pp. 333 – 343.<br>3. The Coast Guard at War: IV LORAN VOLUME II.
+<br>Prepared in the Historical Section Public Information Division U.S. Coast Guard Headquarters in 1 August 1946:<br>[http://www.uscg.mil/History/STATIONS/loran_volume_2.asp http://www.uscg.mil/History/STATIONS/loran_volume_2.asp] <br>[http://www.uscg.mil/history/stations/LORAN_Section_2.asp http://www.uscg.mil/history/stations/LORAN_Section_2.asp] <br>[http://www.uscg.mil/history/stations/LORAN_Volume_1_Index.asp http://www.uscg.mil/history/stations/LORAN_Volume_1_Index.asp]
+<br>4. Other Websites:<br>[http://www.loran-history.info/ http://www.loran-history.info/] <br>http:/ [http://www.jproc.ca/hyperbolic/loran_a.html www.jproc.ca/hyperbolic/loran_a.html] &nbsp;<br>[http://en.wikipedia.org/wiki/LORAN http://en.wikipedia.org/wiki/LORAN] &nbsp;
+To Probe Further:
+Willoughy, Malcolm Francis; The Story of LORAN in the U.S. Coast Guard in World War II, Arno Pro, 1980.
 == Map ==
-{{#display_map:52.2213787, 21.0146535~ ~ ~ ~ ~First Breaking of Enigma Code by the Team of the Polish Cipher Bureau, 1932-1939, Warsaw, Poland|height=250|zoom=10|static=yes|center=52.2213787, 21.0146535}}
+{{#display_map:42.36150, -71.09200~ ~ ~ ~ ~211 Massachusetts Ave., Boston, MA|height=250|zoom=10|static=yes|center=42.36150, -71.09200}}
-[[Category:Cryptography|{{PAGENAME}}]]
-[[Category:Message_systems|{{PAGENAME}}]]