Military Collector Group Post
Backmail #82 (20 pages)

Index:
THE U.S. HUNT FOR AXIS AGENT RADIOS; by George E. Sterling
- Part I, Forward, Policing the Domestic Ether, Radio Spies in the United States.
- Part II, The Portuguese Net, Nazi Agent Training and Procedures,
- Part III, The Latin American Infestation.
BIRTH OF THE "HUFF DUFF"; Direction Finding System, By Feyssac Jacques
- (BC-1147, SCR-291, SCR-502, CRD-3, DAQ, DAJ)
ELECTRONIC COUNTER MEASURES IN W.W.II; The RCM Program,
by Pete. D. Williams VK3IZ
Early Radar, Freya system, X-Gerat, Knickerbein, Wurzburg, Moonshine, MEACON
Devices - Jamming, Airborne Cigar, American Mandrel(RC 183A/T1661), Carpet 11 (TR1621, ARI 5549), Carpet 111 (APQ-9, APR-4), Corona (FuG10), Ground Cigar(USP2, TU4, SWB4, AN/GRQ-1), Ground Grocer, Ground Mandrel, Jostle 1V(ARI 5289), Mandrel 1, Mandrel 111, Pipe Rack(APT-1), Tinsel, Window, Jackal(SCR-522, BC-787, S-27), Silver(R3003AMk22)
Homing/Warning Devices, Boozer (receivers Type 164, 65, 177, 181), Monica (ASV11, ASU MK11), Perfectos.
Airborne Interception Radar, Mk X, SCR-720, Mk XV, APS-4
***********************************************

THE U.S. HUNT FOR AXIS AGENT RADIOS; Part I, George E. Sterling
"Studies In Intelligence" Vol.4 Issue: spring 1960

Part I,

Forward,
- "Studies In Intelligence" was a CIA published in-house magazine that was classified for many years. Last year, Pete McCollum obtained through the Freedom of Information act, several of their now declassified articles. The following is one of those articles.

Dennis
------------------

- How FCC's routine policing of the ether became in World War 11 a multi-purpose defense service and a far-flung counter-espionage operation.

- I hope that this country, particularly its intelligence agencies, has become better organized to handle a national emergency than it was in 1941. When the war, after slowly creeping for two years from Europe toward U.S. shores, suddenly exploded upon us at Pearl Harbor, thousands of new kinds of things had to be undertaken in desperate haste and with at times disorderly improvisation. Many agencies were given emergency duties for no better reason than that they were using equipment approximating what was needed for the wartime work. That they by and large discharged these extraordinary responsibilities well, at the same time helping cooperatively toward the gradual readjustment of temporarily assigned functions, is something in which all those who participated can take pride.

- The Federal Communications Commission, because it had a network of radio monitoring and direction-finding stations to police the domestic airwaves, was given its full share of duties not called for in its job description. It ran a rescue service for planes lost in the black-out or bad weather, locating them by their radio signals and furnishing them their bearings; more than 600 planes, many of which would otherwise have been really lost, were given FCC emergency fixes before Army Air Force personnel were trained, with our help, to take over the job. It monitored enemy commercial radio circuits and furnished the Board of Economic Warfare with hundreds of leads useful- in the preclusive buying program. To meet requirements of the Eastern, Gulf, and Western defense commands, the Commission's legal responsibility for apprehending unlicensed radio stations was extended to surveillance of the coast by radio patrols for signs of surreptitious intercepted foreign weather traffic for our air forces. It monitored foreign radio broadcasts, setting up the organization which now has become the Foreign Broadcast Information Service, and published texts and analyses of broadcast new and propaganda for a variety of government consumers. I trained OSS personnel in radio methods and procedures an built equipment for their use.

- For a year and a quarter the FCC's Radio Intelligence Division, as the monitoring network was known, carried the full load of military radio intelligence in Alaska, where the Army was not able to station a radio intelligence company until late in 1942 and got a monitoring station in operation only in the spring of 1943. It radio-patrolled the Alaskan coast by sea. It also participated at Army request in military intelligence elsewhere, most notably in Hawaii and on the west coast. In San Francisco it set up an Intelligence Center where officers of the military services were on duty around the clock. It identified and tracked the radio-equipped fire bomb/balloons which the Japanese launched against our west coast It discovered and established the location of a Nazi weather station on Greenland, which the Coast Guard was then able to destroy. It trained the military personnel who eventually took over most of these duties, prepared instructional booklets and monitoring aids for them, and supervised their work until they became competent enough to operate without help

- The RID even participated from afar in the guerrilla movements in the Philippines. This activity began when one of our monitors picked up a signal using the call, PKlJC, of an amateur in the Dutch East Indies, where no amateurs could operate. We fixed its origin in northern Luzon. PK1JC sent a message coded, we determined, with a prewar Signal Corp cipher disk, giving the name and serial number of an unsurrendered American soldier trying to establish contact with MacArthur's headquarters. He requested acknowledgement by a signal from General Electric's powerful KGEI transmitter near San Francisco. The Signal Corps arranged for the acknowledgement and asked us to continue copying all messages. Later, when the landing of transmitters by submarine created quite heavy traffic from the Philippine guerrillas, a primary monitoring station at San Leandro, California, was exclusively devoted, at Signal Corps request, to copying it and expediting it by private teletype circuit to Washington.

Policing the Domestic Ether,
- Although these spirited improvisations requested and supported by the military services lay far outside the Commission's proper charter, the Communications Act of 1934, they were undertaken eagerly when required and relinquished later gracefully but with reluctance by our radio men and women anxious to contribute the war effort in any way they could. Our people had enough of their own proper work to do, for after Pearl Harbor the regular job of the Radio Intelligence Division took on a new and grimmer aspect. It was now not just a question of tracking down maladjusted transmitters, unshielded diathermy apparatus, or even the illegal communications of pranksters, smugglers, and racetrack tipsters, but of sealing the country's leaky ether against loss of war secrets over the radio circuits of enemy agents. Hitherto, with commercial communications to foreign countries free of surveillance, spies in this country had had no need to risk secret transmitters; now these commercial facilities were closed or censored and the whole spectrum had to be patrolled for furtive whisperings in Morse cipher. The RID was under challenge to live up to its initials.

- The Division's equipment, personnel, and physical deployment were adequate to the task. During the state of national emergency that preceded Pearl Harbor the FCC had been authorized to begin an expansion of its radio detection facilities, which were ultimately stabilized in twelve primary monitoring stations, about sixty subordinate monitoring posts, and about ninety mobile units distributed through the United States, Puerto Rico, Hawaii, and Alaska. The fixed stations and many of the mobile units were linked by instantaneous communications. They were organized into three major networks based on radio intelligence centers respectively in Washington, near San Francisco, and in Honolulu; but in fixing the location of a source of radio signals the three networks were fused into one and directed from Washington.

- Each primary station, in addition to its complex of rhombic and other antennae and its receiving and recording equipment, had at least one Adcock direction finder, a large rotating antenna sensitive to the direction of short-wave signals bounced off the ionosphere; this device had been invented in England, but was refined and improved by RID engineers. At short range, say within a few miles, a simple loop antenna can pick up the ground-wave component of a signal and determine its direction; our disguised mobile units included these in their equipment. And finally, for locating transmitters at really close quarters, we developed what we called a "snifter," a signal-strength meter that a man could carry in the palm of his hand while inspecting a building to determine which room a signal came from.

- In the routine day-and-night operation of a monitoring station, the patrolman of the ether would cruise his beat, passing up and down the frequencies of the usable radio spectrum, noting the. landmarks of the regular fixed transmissions, recognizing the peculiar modulation of a known transmitter or the characteristic fist of a familiar operator, observing an irregularity in operating procedure and pausing long enough to verify the call letters, or finding a strange signal and recording the traffic for close examination, and then sometimes alerting the nation-wide net to obtain a fix on the location of its source. More than 800 such fixes would be made in an average month, requiring the taking of some 6,000 individual bearings. For although mathematically the intersection of two bearings provides a fix, the 1% error that must in practice be allowed in the angle of a bearing, even when it is corrected for variations in propagation and site conditions, becomes considerable at distances that may run to thousands of miles; and at least four bearings are needed for a reasonably reliable long-range fix.

Radio Spies in the United States,
- With respect to Axis agents in the United States and its territories this close vigilance was almost purely prophylactic, and effective in its prophylaxis: out of respect for it enemy agents, as far as we ourselves were able to discover, made only two attempts during the entire war to establish radio communications across our ethereal frontiers, and in both cases failed to get a single message through.' The stories of these two, although they have been told from other viewpoints elsewhere are worth summarizing here.

- The first took place in the spring of 1940, long before Pearl Harbor had roused us to hunt for radio spies here in earnest. Our routine monitoring turned up an unidentified transmitter carrying on coded traffic with a distant station which used the call AOR. We asked the Army and the Navy if it might be one of theirs. They had no knowledge of it; the Navy thought it might be a St. John, New Brunswick, station. But our direction finders showed it to be on Long Island, and its correspondent AOR near Hamburg, Germany. We reported to the FBI.

- The Bureau told us in confidence that it was indeed a German agent radio, but under their control. A German-American, William Sebold, had revealed that he was recruited by the Nazis and instructed to set it up. The FBI built and now were manning the station for him, feeding Hamburg false or innocuous information and identifying its agent sources. The deception continued for more than a year under our joint surveillance, until at the end of June, 1941, 33 German agents to whom the traffic had furnished leads were arrested. At their trial that fall, when the defense tried to maintain that AOR was not a German station but an FBI entrapment device in the United States, RID engineer Albert McIntosh produced charts showing the fix on Hamburg. His public testimony must have been one factor in the German decision not to risk agent transmitters in the United States.

- They did try it once more, though, right after Pearl Harbor, apparently on local initiative, impromptu. In the general alert which followed that shocking Sunday morning we had put several mobile monitoring units out cruising the Washington streets. These were equipped not only with loop direction finders but with a device we called the watch-dog, an

Footnotes on page 39
' Wilhelm Hoettl, one of the German foreign intelligence area chiefs, affirmed during his interrogation by 3rd Army in June 1945 that the Sicherheitsdienst had not been able to establish a single wireless connection either in the United States or in England. 'Notably in Don Whitehead's The FBI Story.

aperiodic receiver we had developed which would sound an alarm when it received a strong signal on any of a wide range of frequencies. (It was patented by two RID engineers and later used by OSS and the Navy.) In the wee hours of Tuesday, December 9, one of these watch-dogs was triggered by signals on a transatlantic frequency. At the same moment ' three thousand miles away our monitors in Portland, Oregon, heard them too-station VA briefly and vainly calling a distant control center. Five other direction-finding stations were set to watch the frequency; and when a few hours later UA tried it again, they reported the bearings projected on the chart in Figure 1. This fix confirmed the uncertain supposition of the watch-dog that the transmitter was in Washington.

- Now three mobile units were given the scent, and they quickly narrowed down the location to the German Embassy, was shown in Figure 2. It was a problem to pin-point the transmitter without entering the Embassy because the antenna was stretched between two buildings, with equal signal strength at each end and apparently lead-in wires to both buildings. This problem was solved in a pre-dawn conference with the FBI, who arranged, in cooperation with the Potomac Electric Power Co., that we could go down into a manhole in the street and cut the power to each building separately in turn when VA began to call. In the end, however, because the State Department was afraid for our own diplomatic mission still in Germany, we did not seize UA but simply set up two jammers to drown him out if he should try once more. He never did.

- This beginning was the end for Axis radio agents within our borders; any German agents picked up by the FBI thereafter were found to have been using secret ink or some other communications than radio to get information out of the country. And we learned that some Japanese agents who requested their headquarters' permission to set up a transmitter here were turned down on the grounds that the FCC would nab them as soon as they got on the air. Outside our own states and territories it was a different story, one in which also the RID became intimately concerned.

The Portuguese Net, Continued in Part II.
***********************************************
THE U.S. HUNT FOR AXIS AGENT RADIOS;

Part II

The Portuguese Net,
- One day in September 1941, monitors at the secondary post in Miami heard a station using irregular procedures an signing the call UU2, one not in conformity with those used on commercial and other authorized circuits. It was therefore made a case for investigation. Bearings fixed its location near Lisbon, Portugal; and as it continued to call almost nightly without receiving a reply, RID units were instructed to be on the lookout for the answering station. After more than a month monitors at the secondary posts in Pittsburgh and Albuquerque simultaneously picked up the answer from a station signing CNA; bearings were taken which located the transmitter in South Africa.

- A few days later another station using the W2 procedure was intercepted, this time with the call BX7. It was also Lisbon, and the characteristics of its signal showed that with out question BX7 was the same station which had previously signed UU2, apparently the control station of a network. After a week an answer with the call letters NPD was picked up by our Rhode Island monitoring post. This station proved to be in Portuguese West Africa.

- The messages exchanged between the Lisbon control W2 BX7 and the two out-stations in Africa were of course enciphered. RID did not maintain a cryptanalysis laboratory decipherment being the responsibility of the FBI, of the Army's Signal Intelligence Service, and, on behalf of the Navy of the Coast Guard; but in order to facilitate the identification of intercepted traffic we had interested a couple of the staff in cryptanalytic work. These men attained a considerable skill and in some cases were able to furnish leads for the FBI decipherment. The Lisbon cipher was one of these cases It was an up-and-down transposition whose key length varies from day to day.

- The texts of the messages showed this network to be on channel by which German agents in the neutral countries and colonies of Africa reported on the movements of ships troops, and materiel and on political events. On March 26, 1942, for example, the South Africa station reported shipings and the concentration of Allied troops which later took Madagascar. As translated from the Portuguese:

TWENTYSIXTH. AMERICANS "NISHNAHA" AND "SOLONTU-SHAW ' SAILED WITH ORE FOR NEW ORLEANS, ALSO ENGLISH "CITY OF N. CASTLE"; "ANGOLA" AND ENGLISH "ISIPIEGO" FROM DURBAN ARRIVED WITH PASSENGERS. TROOPS STILL CONCENTRATED; TRYING TO LEARN DETAILS.

From Portuguese West Africa an agent with the code-name Armando sent similar information intermingled freely with operational reports. On December 4, 1941:
ARMANDO REPORTS ENGLISH CONSUL RECEIVED LONG ENCIPHERED TELEGRAM RELATIVE ENFORCING STRICT VIGILANCE AGAINST ESPIONAGE. OFFICIALS CLAIMED ENGLISH STILL COMMAND CAPE VERDE SUBMARINE CABLE. MANY MEN GO TO FREETOWN OWING APPROACH TEN CONVOY SHIPS, LARGE TROOPS, AMMUNITION AND TANKS. HOWEVER INFORMER DOES NOT KNOW IF THEY REMAIN LAGOS OR FREETOWN AND BATHURST.

On January 7, 1942:
WEST INDIA ARRIVED BATHURST FOURTEEN WITH PILOTS AIRCRAFT MECHANICS DISASSEMBLED TANKS ANTIAIRCRAFT MACHINE GUNS MUNITIONS LARGE QUANTITY GASOLINE CAMPAIGN TENTS. NEXT MONTH WE WILL HAVE REGULAR CONNECTION DAKAR THROUGH INTELLIGENT NATIVE GOLDSMITH AUTHORIZED TO ENTER COLONIAL SERVICE UNDER GOVERNOR TO HELP MY WORK. ARMANDO

On February 5:
CHIEF OF POLICE LIEUTENANT UNDERCOVER IMPRUDENTLY WORKS FOR ENGLISH. COQ TO OBTAIN HIS RETURN LISBON. HE CAN DAMAGE US. ARMANDO

But the Germans were growing dissatisfied with Armando's work. The Lisbon station radioed him on February 11:
SAID THERE IS TO BE DISEMBARKMENT ENGLISH AMERICAN TROOPS DAKAR NEXT FIFTEEN DAYS. WHY NO REPORTS MOST URGENT.

On February 12:
DISEMBARKATION TROOPS FREETOWN NOT DAKAR. I ORDER YOU INVESTIGATE. NOT SATISFIED REPORTS WHICH I CALL FOR. HAVE RECEIVED BETTER REPORTS FROM OTHER PERSONS r
OFFICIAL ONLY Axis Agent Radio,

And most indiscreetly, on 27 March:
SECURE EXPEDITIOUSLY RECENT REPORTS DAKAR FREE TOWN RELIEVE CAROLINA OF HIS DUTIES. USE NEW I BEARER SHOULD DELIVER LETTERS PERSONALLY TO PORTER HOTEL DUAS HACOES VICTORIA STREET FOR MERCKEL. WE ARE EXPERIMENTING CONTINUATION ORGANIZATION TWO MORE MONTHS. USE YOUR BEST REPORT FOR MY VINDICATION.

- The organization did not in fact last much longer than two more months, but it was not the Germans who terminated it. Revelations like this one enabled Allied intelligence officers to clean out the Portuguese group in the summer o 1942.

Nazi Agent Training and Procedures,
- Having thus demonstrated its capability in the European theater, the RID was approached early in 1942 by its British counterpart, the Radio Security Service, with a request for the establishment of regular liaison and exchange of information. From then on to the end of the war we maintained a most harmonious and fruitful relationship which served to build up a pretty complete picture of the German diplomatic and espionage networks and their activities. The characteristics of individual transmitters and individual operators were recorded and catalogued so that they could be recognize when they were used on a different circuit. Nearly all the codes and ciphers were broken, and the great bulk of the clandestine traffic could be promptly read. During the most critical period of the war in Europe the RID was monitoring 222 frequencies used in clandestine intra-European circuits.

- After the Lisbon net was closed down the Germans had five major networks, with control centers in Berlin, Hamburg, Bordeaux, Madrid, and Paris. The out-stations were located in practically every European country, in Africa and the Atlantic, and in the western hemisphere. The operators of these out-stations were in general not skilled radiomen, we learned from captured spies, but agents who had been trained in radio and codes and ciphers along with other tradecraft-for example photography and microfilm, secret writing, explosives and demolition-at a school near Hamburg. Their radio training embraced the use of International Morse and the construction and operation of transmitters and receivers.

- Student operators were required to achieve the modest transmitting speed of twelve words a minute (as compared, for example, with our Merchant Marine requirement of 20-25 words a minute). Then they would make a five-minute sample transmission on a device which recorded graphically their speed, touch, and characteristic fist. On the basis of this graph they were assigned a permanent transmitting speed and given another week's training at this speed. Then a second graph was made as each operator graduated, this one to be filed as a specimen signature against which his later messages would be verified as genuine and not the deception of enemy counterespionage. This procedure was apparently adopted after the Germans learned that the FBI had fooled them with the Sebold station on Long Island.

- The agents were furnished portable transmitters and receivers, usually of the type built into a suitcase, complete with antenna, wire, tools, and all the accessories necessary for going into immediate operation. They were given precise instructions for constructing a directional antenna which would afford a maximum signal to their control center and a minimum to eavesdroppers. Then they were dispatched to their posts by neutral ship, by submarine, by parachute, or over clandestine land routes.

- The first sign of their safe arrival would be their call letters on the air; and this would signify their presence to us, too, for it is difficult to disguise an agent radio's call. At one time, when the control of one of the German nets passed from the Abwehr to the Gestapo, its transmitters adopted the call letters and frequencies of commercial stations in South America; but other characteristic procedures of clandestine traffic still betrayed them, and this device was later abandoned.

- Not being able to disguise their calls, the agent networks made a practice of changing call letters, usually every day, in an effort to spoil continuity for their pursuers. But very few had a rota which remained nonrepetitive for a year, say, and we were able to work out in advance the call letters which many espionage transmitters would be using on any particular future day; sometimes we even caught the out stations making mistakes in their own system. Some work with a list of 31 different calls which repeated itself every month. Some had two such lists, one for odd and one for even months. One system was worked out with such little forethought that a spy once had to call with the international distress signal, SOS. This was one of the systems that determined call letters in connection with the cipher key for the day, a connection that sometimes led our part-time crypt analysts into the decipherment of messages.

- One group, we learned from one of its indiscreet first messages sent blind, based its calls and transposition cipher on the Albatross edition of Axel Munthe's The Stony of Sa Michele, a book excluded by copyright arrangements from the British Empire and the United States, using a different page each day. The page to be used was determined by adding a constant number assigned each agent the number of the month and that of the day in question. The last line of this page contained the calls to be used-the first three letters, reversed, for the control center and the last three, reversed, for the out-station. An example of this procedure may be of interest.

- Shortly before midnight, eastern standard time, on March 12, 1942, one of our monitors at Laredo, Texas, copies the following slow hand-keyed message on 11,220 kilocycles.

VVVV EVI EVI EVI

IWEOF WONUG IUVBJ DLVCP NABRS CARTM IELFIX YEERX DEXUE VCCXP EXEEM OEUNM CMIRL XRTFO CXQYX EXISV NXMAH GRSML ZPEMS NQXXX ETNIX AAEXV UXURA FOEAH XUEUT AFXEH EHTEN NMFXA XNZOR ECSEI OAINE MRCFX SENSD PELXA HPRE

- We know from our analysis of previous messages that the call EVI is due to be used by an operator of the San Michel group whose assigned constant number is 56. Checking, we add the month and day-this would be March 13 by Greenwich Mean Time-and turn to page 72 of the novel. The last word on the page is "give," so EVI is right. The first word on the last line is "like"; the control center will sign KIL.

- The message sent in the early hours of March 13 was probably enciphered on March 12, so we go back to page 71, shown here opposite, for the key. Here the first line reads, "I would have known how to master his fear, and would have been the stronger of the two as I have been in later years more than once, when I have stayed a hand clutching a revolver in fear of life.

- When will the anti-vivisectionists realize that when they are asking for total prohibition of experimentation on living animals they are asking for what it is impossible to grant them? Pasteur's vaccination against rabies has reduced the; mortality in this terrible disease to a minimum and Behring's anti-diphtheric serum saves the lives of over a hundred thousand children every year. Are not these two facts alone sufficient to make these well-meaning lovers of animals understand that discoverers of new worlds like Pasteur, of new remedies against hitherto incurable diseases like Koch, Ehrlich and Behring must be left to pursue their researches unhampered by restrictions and undisturbed by interference from outsiders. Those to be left a free hand are besides so few that they can be counted on one's fingers. For the rest no doubt most severe restrictions should be insisted upon, perhaps even total prohibition. But I go further. One of the most weighty arguments against several of these experiments on living animals is that their practical value is much reduced, owing to the fundamental difference from a pathological and physiological point of view between the bodies of men and the bodies of animals. But why should these experiments be limited to the bodies of animals, why should they not be carried out on the living body of man as well? Why should not the born criminals, the chronic evil-doers, condemned to waste their remaining life in prison, useless and often dangerous to others and to themselves, why should not these inveterate offenders against our laws be offered a reduction of their penal servitude if they were willing to submit under anesthetics to certain experiments on their living bodies for the benefit of mankind? If the judge, before putting on the black cap, bad in his power to offer the murderer the alternative between the gallows and penal servitude for so and so many years, I have little doubt there would be no lack of candidates. Why should not Doctor Woronoff, the practical value of his invention be have known how to master his fear" etc. We take the first nine letters and number them in sequence:'

I W O U L D H A V
1 2 3 4 5 6 7 8 9

Substituting these figures in the first four groups, with n for any missing letters, we get
I W E O F W O N U G I U V I3 J D L V C R
1 2 x 3 x 2 3 x 4x 1 4 9 x x 6 5 9 x x

or "12 March, 2304 hours, 149 letters in 659th message following." There are actually 154 letters following, but the first group of five is simply a special indicator identifying the agent.

- This is as far as the RID needed to go for its own purpose before turning the message over to the FBI. But the to could be worked out from the same page of the novel. Lay out a blank message in lines of twenty letters each, keeping the columns straight. 149 letters in rows of 20 make nine columns of eight letters each followed by eleven columns of seven each. Write across the top the first twenty initial letters of the lines on page 71, skipping indented lines. Number these in alphabetical sequence, and then go down the column in the indicated order with the encrypted text. This arrangement gives the clear German text:

i b m r a a t m a t s u n e u f f n p t 8 4 9 14 1 2 16 10 3 17 15 19 11 5 20 6 7 12 13 18 S P R U C H x S E C H S N U L L x V O N V E S T A x A N x S T E I N x x Q U E E N x M A R Y x Q U E E N x M A R Y x A M x E L F T E N x E I N S A C H T x U H R M E Z x M 1: Z x V O N D A M P F E R x C A M P E I R O x C A M P E I R O x A U F H O E H E x It E C I F E x R E C I F E x G E M E L D E T x

In English:
TEXT SIXTY FROM VESTA TO STEIN. QUEEN MARY REPORTED OFF RECIFE BY STEAMSHIP CAMPEIRO ON ELEVENTH AT EIGHTEEN O'CLOCK MIDDLE EUROPEAN TIME.

The Latin American Infestation continued in Part III.
***********************************************

THE U.S. HUNT FOR AXIS AGENT RADIOS;

Part III,

The Latin American Infestation.
- The Queen Mary message, from an agent in Rio de Janeiro; came at a moment of climax in RID's most active and critical theater of counterespionage operations, Latin America. There were in March of 1942 six agent transmitters in Rio alone, and three of them reported the Queen Mary's arrival on the twelfth. The espionage messages were full of news about her until after she sailed on March 20, but these were . the last messages most of the agents sent. By the time she was again in mid-Atlantic on a safely altered course, the Brazilian authorities had arrested some 200 of the German spies.

The story behind this roundup is first of all an RID story.'
- Signs of the Nazi effort to create an espionage base in Latin America began to be apparent as early as the fall of 1940. On October 27 our primary station at Allegan, Michigan, picked up a strange maritime signal using the unregistered call BCNL. Other monitoring posts were alerted, and quite a number of similar calls were traced to ships in the Gulf of Mexico and Caribbean Sea. The FCC's Tampa office succeeded in identifying these vessels as small ones operated by a firm called Gough Bros. and controlled by a coastal station near Belize in British Honduras. The U.S. Caribbean Defense Command, after developing evidence that this fleet was being used to refuel German submarines and pass information, arrested a Canal Zone employee who was a member of the ring and was able to arrange a trap for nineteen others, including the ringleader, prominent British shipping executive George Gough, in Belize.

- Meanwhile in Mexico a German spy was sending out intelligence reports in private code over Chapultepec Radio, the same transmitter used for clandestine communication with Berlin during the first world war. After Pearl Harbor, when the use of code on commercial facilities was prohibited in Mexico, this man, a properly registered amateur, resorted to his own clandestine radio, but made the mistake of communicating first with the FBI's deception station on Long Island.

- The concerted German drive to establish radio agent nets in this hemisphere, however, and our struggle against them, began in the spring of 1941. One of our monitors at Millis, Massachusetts, detected the faint signals of a station that was trying to hide its transmission in a transatlantic radiotelephone circuit operating on the same frequency. It was repeating the ball letters REW, but the signal sounded quite like that of AOR, the FBI-operated Sebold transmitter's respondent. Other monitoring stations, asked to help identify the suspicious and noise-shrouded signal, discovered that when REW paused to listen a station on a different frequency would start sending the call letters PYL. The two transmitters put on the same performance at the same hour the next day, and for several days; they were apparently trying with out success to communicate with each other. One of our monitors became so engrossed that he wanted to go on the air and help them out. Our fixes showed that REW was in deed in Hamburg, and PYL in Valparaiso, Chile, an espionage station discovered before it could make contact with its base

- For the present, however, there was nothing that could b done about agent radios outside U.S. jurisdiction except listen in, and more and more of them began to appear, setting up in a half dozen of the Latin American republics. Chili and Brazil held the principal concentrations at this time. There were three main agent networks in Brazil, centered on transmitters that we designated LIR, CEL, and CIT, from the call signs they were using when first heard; the EVI of our decipherment example was LIR. Evidence of the damage they could do began to mount.

- The German control stations, for example, sent exhaustive lists of requirements for naval information, asked PYL Chile if it could "place a suitable man for us among students going to the United States for air training," complimented agents as "exceptionally correct" in their reports on technical. details of English and American cruisers' equipment, and assigned agents to investigate "USA parade and air bases in Colombia and Venezuela" and "air units Trinidad and Lesser Antilles and flights via those places to West Africa; airplane types, movement, dates." The agent radios sent back reports like these:

5 JULY. NINE BOEINGS FLEW WITH Mired CREW ENGLISH AND AMERICANS. IN NEXT FEW WEEKS 20 MORE TO BE FLOWN ACROSS. DETAILS FOLLOW.

19 JULY. LM REPORTS 15 LOCKHEED HUDSONS FLEW ACROSS. ENGLISH REGISTRY AND CANADIAN-AUSTRALIAN CREW. BOEING CLIPPER LEFT NATAL ON SEVENTH ALLEGEDLY FOR BOLANO WITH 19 LOCKHEED MECHANICS AND 1 CREW.

7 AUGUST. USA STEAMER URUGUAY ON LAST VOYAGE TO UNITED STATES LEFT RIO 25 JUNE. WAS CONVOYED BY BRITISH AUXILIARY CRUISER CARNARVON CASTLE TO TRINIDAD TRIP TAKES 7 DAYS. CRUISER TRAVELED SOMETIMES AHEAD SOMETIMES ASTERN OF SS URUGUAY.

8 OCTOBER. BMM REPORTS SEVERAL HUNDRED US AIRCRAFT OF VARIOUS TYPES AND 8000 SPECIAL TROOPS ALLEGEDLY LANDING CORPS BEING ASSEMBLED PORT OF SPAIN.

- In November PYL identified a network courier as "daughter of Clarke, secretary in USA embassy Quito since 1 November." And ten days after Pearl Harbor an agent offered details on the torpedo safety nets with which ships were being equipped and also "absolutely safe men . . . who will send to bottom two or three large armed English ships . . . without any suspicion falling on us. If we are interested payment only after sinking, nothing in advance." The control station in Germany of course approved: "Proposal for destruction of ships very interesting." Reports on plane production also now began in earnest:

1 JANUARY. CURTISS COLUMBUS FACTORY WILL BEGIN MASS PRODUCTION SERIES SB2C SINGLE SEATER STUKA FOR NAVY. ARMAMENT ONE CANNON FIVE MACHINE GUNS, MOTOR 1700 HP WRIGHT. BUILT FOR 2000 HP WRIGHT IN EXPERIMENTAL STAGE. PRODUCTION S03C BEGUN IN COLUMBUS FACTORY AT BEGINNING DECEMBER. EMPLOYEES ALL CURTISS AIRCRAFT FACTORIES DECEMBER TOTAL 27000. PROPELLER PRODUCTION NOVEMBER 1042.

- Our Government finally took action. On January 15, 1942, the Rio conference of foreign ministers of the American republics recommended immediate measures to eliminate the clandestine stations. An Emergency Advisory Committee for Political Defense was established with headquarters in Uruguay, and under its auspices we dispatched some of the best RID monitoring officers to the six countries where we knew agent radios to be operating (Brazil, Chile, Mexico, Cuba, Martinique, Paraguay). They had a two-fold mission-to locate the hide-outs of known agent transmitters with mobile direction-finding equipment they took along, and to help the governments of these countries establish monitoring networks which could keep them free of radio spies in the future. For this second purpose we sent men also to six other countries (Haiti, Venezuela, Colombia, Ecuador, Peru, Uruguay, Forty men from eighteen Latin American republics were at the same time brought here for training at our school in Laurel, Maryland.

- The man we sent to Brazil was Robert D. Linx. He helped lay the groundwork for that arrest of 200-odd spies after the Queen Mary left her dock in March. This roundup apparently cleaned out the LIR and CIT organizations, the latter led by a man named Christiansen; they were never heard again. Some members of the CEL net escaped to the interior, but two series of arrests after they ventured twice at intervals to reactivate their transmitter put an end to that too. By mid-year Brazil was permanently cured of its agent radio infestation. Linx stayed on to direct the establishment of the monitoring service, and became known as "the father of Brazilian monitoring."

- Although our men in Latin America worked quietly by them selves as much as possible, the German agents were not always unaware of what was going on. We heard one of them telling his control that he knew at least six Yankee direction finders were beamed on him and he was going to cool off in the woods for a while. (He cooled off in a Central American jail.) In Chile, the PYL organization took the precaution of establishing a stand-by transmitter to assure continuity of communication if one should be seized. On March 9 PYL sent a message informing Hamburg that "Pedro", whom they had employed to operate the new transmitter, would be read to get on the air the following day. On March 10, although RID had not yet received the decrypted text of this message our monitors picked up Pedro's test transmission with the call GES and fixed his location in Antofagasta.

- The arrival of our man, John de Bardeleben, in Valparaiso on March 19 was the signal for* the main PYL transmitter to go mobile. De Bardeleben spent weeks tracking its changing locations in the area within a ten-mile radius of Valparaiso. It developed that every second week, however, a transmission would be made from the house at Avenida Alemana 5508, Cerro Alegre. This house belonged to one Guillermo Zeller, a radio technician and licensed amateur who was often seen in the company of Hans Blume, manager of the Valparaiso branch of the German company Transradio. In April 1941, shortly before PYL was first heard trying to contact REW, Blume had bought from the radio supply store Casa Widow a complete set of transmitter parts and two Hallicrafter receivers. A tap was now placed on the Zeller telephone.

- The Chilean authorities were persuaded to raid the Zeller house on June 25. Their perfunctory search discovered no transmitter, but Zeller was indiscreet enough to telephone afterwards to one of his agent colleagues and report his narrow escape: "Lucky they didn't search very good, especially in the basement." With some trouble and delay another search warrant was obtained, again to no avail; the officers didn't bother to open a box they noticed in the basement purporting to contain a sewing machine. PYL went off the air after this, and nothing could be done until after many weeks De Baxdeleben found the transmitter in its sewing machine box stored in a grocery on Cerro Alegre. Finally, on October 23, most of the agents of the PYL organization were arrested; but the man who actually operated the main transmitter and operator Pedro at Antofagasta had disappeared.

- Neutralist Argentina, which did not participate in the Emergency Advisory Committee, posed a delicate diplomatic problem with respect to the elimination of clandestine enemy transmitters, and one of critical importance as the clean-up in Brazil and Chile made the Argentine the main base for espionage activity in this hemisphere. Not only agent radios but the powerful Argentine commercial transmitters were carrying quantities of compromising information to Italy, Japan, and Germany, and we could only copy their transmissions, hundreds of messages daily. Many of these were at speeds too high for manual copy; we recorded them on tape and trained selected typists to put them into page form. A strong memorandum from the U.S. Government on January 4, 1943, enabled us to send two men to Argentina to try to do what we had done in Brazil and Chile, but our earlier successes were not repeated here. The agent operations had become much more sophisticated. While our men were taking bearings on a signal the transmission would be cut off that location and picked up by another transmitter several miles away. And the cooperation of Argentine officials under the Castillo and Ramirez-Peron regimes was less than eager. They finally became so resentful of U.S. Government pressures that we had to withdraw our men.

- One spy who escaped in Chile, however, did not get as far as Argentina. Almost a year after the incomplete catch of the PYL ring in Chile, monitors at three different RID post, heard a new station with the call PQZ, and all three were sure they recognized the fist of operator Pedro of the GES station at Antofagasta. Bearings placed the transmitter at Santiago, Chile.

- De Bardeleben's successor in Chile, William Fellows, was notified, and he picked up the signal the next time it came on the air. Working alone, he had to move around and take bearings from different locations in order to get a fix; but after two more PQZ transmissions he had the house located. To my considerable personal satisfaction the operator Pedro, graduate of the Hamburg spy school, who had the effrontery to use my own initials as his clandestine call, was arrested and his equipment seized. With this postlude there ended except for the Argentine hold-out, the story of radio spies the Americas.
***********************************************

BIRTH OF THE "HUFF DUFF"; By Feyssac Jacques

- During the coarse of the second war we saw great developments of electronics communications and navigation equipment that would change the coarse of the war, many were based on former studies made during the prewar period, such is the case of the High Frequency Direction Finder or more specially the High Speed Direction Finder.

ORIGINS,
- The localization of unknown transmitters was put in pratice during the First War and this DF section of the Army did have much success against German transmitters. The beginning of aviation did soon demonstrate the necessity of Ground D.F. to help the airplanes during difficult wheather conditions, by 1923 eigth stations in France and six in the UK were already operating. Ten years later Europe and North Africa were covered by ground stations operating in the long wave bands used to communicate with airplanes. At the beginning the aerial system was a classic manually rotating loop, but due to the frequencies used the bearing readings at night were often in error due to the night effect , (broad null caused by the reception of the reflected signal with a different polarization).

- An aerial system without the night effect was patented in 1919 by Franck Adcock, but it wasn't till 1930 that the first stations using this aerial were build; it consisted of four vertical antennas with a cathode follower in the base that provided a constant gain in the 10 to 200 metre waves. It had four antennas arranged in each corner of a square and a fifth in the center used for sensing.

WHERE THE STORY BEGINS
- It was in France that a young engineer named H. BUSIGNIES took a patent in 1926 for a DF with automatic Right/Left indication. Following his studies at LMT Laboratories (Remember ITT Group !) This materialized in 1932 in an airborne automatic HFDF with 360° indicator model RC-5; which was officially adopted by the French Airforce. The system was based on a rotating loop of 30 centimetres at a speed of 300 RPM, a di-phase generator was rotating with the loop and gave reference signals in the indicator and the cardoid signal was the variable one. The accuracy was 2 degrees.

- In 1938 the French Navy requested of Mr DELORAINE general manager of LMT, for a short wave direction finder able to locate a signal of short duration; the study was under the responsibility of Mr BUSIGNIES; by the beginning of the 1940 a prototype was ready and operating. It was based on the use of the Adcock aerial system; a goniometer made of a stator with two crossed windings connected to the vertical antennas and a rotor with an output winding connected to the receiver antenna, the speed was 1200 RPM.

- The output signal of the receiver was sent to a rotating coil around the neck of a cathode ray tube , the speed and position was synchronized with the goniometer. A signal at the receiver would maintaining a spot at the center of the CRT, but when the antenna passed null(minimum signal strenght) positions, the spot jumped to the exterior of the CRT screen resulting in a flat double ellipsoid.

- After the "Armistice" of the 8/8/1940 the prototype was hidden so as not to fall into German hands. Soon after, the American Embassador in Vichy offered to alow Mr DELORAINE to emigrate to the USA with some of his engineers; with him were Mr BUSIGNIES, Mr LABIN, Mr CHEVIGNY and all their families. They started a long journey that brought them to New York in December, after a difficult crossing through Spain, Morocco and Portugal. They brought with them all the drawings of the HFDF .

WAR TIME AT FEDERAL TELECOMMUNICATION LABORATORIES
- The Federal Telecommunication Laboratories was created in the beginning of 1941 at Great River (Long Island NY.) with 200 people in the beginning, This count would raise to 950 in 1945. The US Navy who had been impressed with the proposed capabilities of their system, requested of the French team to began the rebuilding of thier prototype. After succesfull testing a first order of 100 units were built, an assigned the nomenclature of SCR-291; they were deployed to 25 stations (4 sets per stations) along the US coasts from Greenland to Florida and Brazil. This network was assigned the task of locating the German submarines operating in the Atlantic. The reason of four sets per stations was simple, to monitor simultaneously four different frequency bands used by the "Kriegmarine".

- This equipment was designed to be air-transportable, with telescoping plywood masts for the antennas and the use of a new flexible high frequency coaxial cables. The receiver BC-1147 had a coverage of 1.5 to 30 Mhz, but the operating range was restricted to 2 to 10 Mhz due to limitations in the antenna system. A portable variable frequency test generator was used to calibrate the aerial system[commonly called a "target transmitter", these were a low power transmitter on the order of 1 watt or less, that was placed at known a distance & bearing from the antenna array to allow their calibration. In this case the BC-1149 was used]. This SCR-291 gave birth to another set, the SCR-502 , this unit was supplied with a collapsible shelter and two sets of 5 aerials to permit DF operations up to 30 Mhz, all the rest of equipment was similar to the 291 with the adjunction of switching facilities and was mounted in permanent wood chests.

- By the end of the war, more than 1500 sets of both types were delivered and in use all around the world. In May 1942 comparative tests were made onboard the destroyer CORRY between a British HFDF type FH-3 and a DAJ[Navy SCR-291?] receiver from FTL. The DAJ won the contest which resulted in 1700 units being ordered. In the shipboard configuration, the Adcock aerials were replaced by two crossed loops installed on top of the mast. They became invaluable in the hunting of German submarines, and the term "Huff-Duff" became their famous nickname. In 1944 the receiver was improved and became the DAQ type with the addition of a panoramic which would allow seeing signals of very short duration.

THE AFTER WAR PERIOD
- The lives of these French engineers who remained in the USA was remarkable: Mr Maurice Deloraine (born 1898) entered Western Electric in 21, ITT in 25, created and managed LMT (Paris) from 28 to 40, director of FTL from 41 to 44, General technical manager of ITT from 45 to 59, president of LMT from 55 to 65; was also vice president of IEEE.

- Mr Busignies (born 1905) engineer at LMT from 28 to 40, was successively technical director, vice president then president of FTL, became vice president of ITT in 60, then scientific advisor in 65 (took 140 patents in the field of radio navigation)

RÉFÉRENCES
-ITT journal, Electrical communication, War Years' Review-Part II, 1946
-De la Tsf a l'Electronique. A. VASSEUR. Editions Techniques et scientifiques Francaises 1975

Best regards
Feyssac Jacques
<FEYSSACJ@aol.com>

Ed) The SCR-502 is identical to the SCR-291 with the addition of a second antenna array to extend the system range to 1.5-30mc. You wonder why the great difference in these numbers. The same basic system was adopted in various forms, with their associated different SCR designations as their use in the field might dictate. The 200 series is most often associated with early radar, the 500, Intelligence. The CRD-3 was very similar but used extensively to aid in aircraft navigation.

- The below was extracted from another book(in the works), "Military Radio Equipment Vol. II, (SCR Designated Equipment)".

SCR-291; Field transportable, direction finding,receiver system. Purchased for the exclusive use by the Army Air Corps, & lend lease(circa 1942) to in part replace the SCR-551. The SCR-291 was used to direct the flight of friendly aircraft, & to track the progression of the enemies. This was accomplished by triangulating & computing their positions, & headings by DF'ing the aircraft's transmitters, thus supplementing or augmenting the use of radar.

- Developed from the SCR-502(used by Radio Intelligence), the SCR-291 was a large set that employed fixed vertical monopole antennas (modified U-Adcock), that were electronically rotated(goniometer). This provided instantaneous bearing indications. The system(with a combined weight of 6900 lbs), was transported by air or truck, then set up for field operation. Operation was over the 2-10mc range, from 110vac provided by a gas powered motor generator.

- System components include; BC-1147 receiver, PN-31 control panel, PN-32 telephone panel,& FM-61 rack, all these transported in CH-161 chest(37h x 28w x 29"d,400 lbs). MC-412 goniometer unit, BC-1159 bearing indicator, transported in CH-162 chest(26h x 16w x 48"d,212 lbs). BC-1149 target transmitter. HO-20 equipment shelter, transported in 3ea crates (17h x 40w x 73"d,595 lbs). HO-19 generator shelter, transported in one crate(14h x 49w x 65"d,368 lbs). 7ea RC-223 antennas,transported in 3ea crates(21h x 22w x 112"d,390 lbs. Evens HV-203000 gasoline heater, 2ea Kohler 1M21A gas generators(35h x 15w x 37"d,497 lbs)...Ref.#6, 91C
#6.TM11-227, 10 Apr 1944, Signal Communication Equipment Directory, Radio Communication Equipment.

Complete, and detailed information on all these systems can be found in:
"Radio Direction Finding", TM11-476, 1947.

Dennis Starks; Collector/Historian
Midwest Military Communications Museum
email: military-radio-guy@juno.com

-----------------------------------------------------------------

There is a mint Federal mfg. (1944) Huff Duff rcvr. at the NTC-GL Museum, in Illinois.(Great Lakes Military Museum)

Don Helgeson, G&S
<helgeson@starnetinc.net>

Hello Dennis
Thanks you for adding your comments to my paper; concerning the TM 11 476 1947 do you know where to get a copy of this book (ready to pay)?
I hope that quickly we will have our own web site and thanks for that.
Receive my best regards

Jacques
<FEYSSACJ@aol.com>

Ed) There were only two military TM's devoted to Direction finding that I know of. I have them both in my library, but to my knowledge these are the only surviving examples. Of these, the first was the most comprehensive and includes both descriptions/photos of the equipment, and operational instructions. In addition, info on DF systems can be found in TM11-227, 1944, Signal Communication Equipment Directory, Radio Communication Equipment(125 pages). If we can find a member in the U.S. willing to make copies for Group members I would loan them out. While the TM11-227, & TM11-487D aren't too bad, TM11-476 is a rather thick manual.

#1, TM11-476, 1947, Radio Direction Finding. (about 325 pages)
#2, TM11-487D, 1958, Directory of U.S. Army Signal Equipments, Radio Direction Finding Equipment.(127 pages)

Dear Dennis,
Apologies for missing the HF D/F posting opportunity so kindly sent to me. Amidst holiday doings my phone company changed the area code and all was not well in their system nor mine, simple though that be. Time shall be set aside to provide information requested and get busy soon after year-end. Hopefully, hands-on experience with SCR-291-291A and photos here will add to our interests. Might there be interest in in Sig Corps SCS-1/SCS-2 a British fighter control system using VHF D/F replicated by the AAF? If so, I can develop a line for same.

The D/F info provided by Feyssac Jacques and you added to my insight. I'll get E-mail off to FJ in appreciation of his contribution. Hopefully, my hands-on experience with SCR-291-291A and photos here will add to our interests.

Meanwhile, best wishes for the holiday season. Again, thanks for putting me in the loop.

Jim Chase
Amateur Airways & Air Communications System Historian
<j.f.chase@worldnet.att.net>

Hi F.J.,
This note salutes you meaningful article BIRTH OF THE HUFF DUFF, etc. I am a newcomer to the group and Dennis Starks is doing his best to huff me off my duff, so to speak.

An amateur historian, age 76, I specialize in activities of the USAAF Army Airways Communication System and USAF Airways & Air Communications Service (AACS). HF and VHF D/F are special interests stemming from WWII China encounters and Greenland (52/53). I must not get ahead of myself since obligations to Dennis for info have not been fulfilled. Suffice to say I also have info about Pan American Airways HF D/F instituted by Hugo Leuteritz and recently scanned material to disk from SECRET WEAPON: etc., authored by Kathleen Boome Williams, 1996. Her book mirrors much of your article content though you identified things she did not despite contacts with Mrs. Busignies.

I am looking forward to exchanges with you, Dennis and the group - better first get busy with info to D.S. Until next time, best wishes for a joyous holiday season and prosperous new year.

Jim Chase
Amateur Airways & Air Communications System Historian
<j.f.chase@worldnet.att.net>
***********************************************

ELECTRONIC COUNTER MEASURES IN W.W.II;
The RCM Program, by Pete. D. Williams VK3IZ

Early Radar,
- The development of R.C.M(Radio Counter Measures). WW 2 had its beginnings when the practice of "seeing" with radio energy i.e. radar was being developed, refined and implemented on both sides of the Channel. The mid 1930's set the scene for defence (R.A.F.) to look for a means of improving home defences - a deteriorating international situation stimulated the action.

- Direction finding was one suggestion - radar came of age in 1936 when a bomber was detected during the first trial at a distance of 8 miles. One year later, the system was detecting aircraft at 100 miles using, in both cases, a short wave transmitter.

- Naturallly, the benefits of this development were translated into a form usable by Fighter Command, with consideration given to the way in which an enemy could interfere with such a system. On the other side of Europe, the German Navy signal research dept. had a fully developed Freya System operational and installed at the end of 1936, with a range of 50 miles, used by both Navy and Airforce.

- At the outbreak of war, Britain was essentially on the defensive and use of counter-measures was in this vein. The story of "the beams" - German blind-bombing devices (X-Gerat and Knickerbein) has been well documented in story and film, as has the tale of British modified diathermy machines to transmit a mush of noise over the Knickebein frequencies to minimise the enemy's system.

- Before developing "jammers", the Research Establishment had to know what it was to jam. The Freya system used by the Navy was confirmed as a radar when the "Graf Spee" was examined, partly sunk in the River Plate. Operating frequency was not definitely known until a reconnaissance Spitfire photographed the antenna array which defined the frequency of about 120mc. Twenty- seven locations were subsequently identified along the western seaboard of Europe.

- A second radar proved to be more difficult - the Wurzburg set at Bruneval on the coast had been identified but lacked important information on frequency. A daring parachutist raid on Bruneval produced one operator, the radar receiver, modulator, transmitter and antenna dipole. Frequency of this one was found to be 520 mc.

- Although the enemy's capabilities were partially revealed, inertia by the authorities gave the Germans a tremendous advantage, highlighted by the sailing back to German waters of the cruisers "Scharnhorst" and "Gneisenau", under the nose of the British, assisted in no small part by the jamming of the British radar. Faced with this embarrassment, the authorities were forced to develop the RCM program.

- In the air, means had to be found to counter the enemy's electronic aids, as the rising losses were directly related to German radio and radar aids which had been incorporated into their defensive system. Conservative Bomber Command until now, had maintained that radio silence must be kept to operate successfully, but the introduction of navigation aids to overcome problems experienced by bomber crews meant that the radio silence had to be broken by transmissions both to and from aircraft. These truths eventually resulted in acceptance by Bomber Command of RCM, although Fighter Command had already enthusiastically endorsed it.

- Early RCM - Early counter measures and the first offensive jammer, "Moonshine", came directly from the technology developed during the Battle of the Beams(Knickebein). Spurious returns on the enemy's Freya Radar were worked by re-transmitting the apparent echo. The resulting blip had the appearance of an extremely large target or of a compact formation of several aircraft-one A/C carrying "Moonshine" could appear as several and a group, the appearance of a sizeable aid!

- Early in 1940 another development was beacon masking or MEACON, which picked up the enemy signals and re-transmitted them exactly in phase - aircrews' faith in their navigation beam, thus distorted, would be considerably reduced. Additional confusion was created by adding an extra crew member- who could speak German and was trained in verbal jamming - to the standard Lancaster bombers. Issuing contradictory instructions, purporting to come from a German fighter controller, assisted the electronic jamming procedures. This technique was limited for fear that the true target might be inadvertently revealed.

- The reticence of Bomber Command to embrace the benefits of RCM was finally overcome in December 1943 when "over-riding priority in labour and materials over all conflicting claims," should be given to the necessary electronic equipment. Subsequently a variety of aircraft was employed with specific functions/equipment to minimise enemy perception, once frequencies and operating details were known.

Devices - Jamming:
- Some produced electronic noise and others audio to disrupt R/T traffic. Listed alphabetically and used with varying success are some of the following with their code names.

Airborne Cigar - disrupted R/T channels on spot frequencies 38-42, 30-33 or 48-52mc. Used 3x50 watt transmitter 1260B, three antennas, 3 power units and a whip antenna for the receiver. The jamming signal was a musical, warbling note.

American Mandrel - used to jam the enemy EW radar 85-135 mc band (Freya etal). It had a modulator, tx, power pack in a single unit and a dipole antenna. The transmitter was pretuned to a 10 mc band within the operating range. 2 watts output, only used for a short time. Service designation was RC 183A/T1661. It was also modified to cover 63-203mc.

Carpet 11 - used for jamming Wurzberg radars 300-600mc. It used a TR1621 tx/rx. Type 210 indicator and Type 315 1/4 wave antenna. Noise modulated jamming was transmitted for 8 minutes after a search sweep identified a radar. RAF designation was ARI 5549.

Carpet 111 (US designation AN/APQ-9 and AN/APR-4) Designed to spot radar in 475-585mc band. Three of the tx were used with an AN/APR-4 rx. The operator swept 300-1000 mc band - semi automatic, and if radar were found, one of the transmitters was tuned to the frequency and the signal was jammed.

[Ed) note, originally, the APR-4 was supplied with a set of tuning units, each covering only a small portion of the 30-1000mc range, and most require it's operator to manually sweep across it's frequency range. Towards the later part of the war some tuning units were supplied with motor drive. The last innovation was the CV-253/ALR which covered the entire 30-1000mc range with a single 4 band tuning unit.This tuning unit was motor drive, and would automatically search the entire spectrum and stop on an active frequency. Hence, this might be considered the worlds first "scanner", as they are termed by the layman today.]

Corona - was a 2.5-6mc jamming procedure using ground tx to disrupt night fighter R/T control links. RX used were captured FuG10 receivers. Initial jamming was misleading instructions from German speaking personnel. Later transmission of 3 or 4 superimposed German voices was used.

Ground Cigar - used to disrupt night fighter control channels 38-42mc. Fifteen transmitters were used, each being spot tuned to a part of the band. Types used were USP2, TU4, SWB4 and AN/GRQ-1, an American 50 KW TV transmitter.

Ground Grocer - jammed radar in 480-500mc band. The radar's range reduced to 1500 feet when the carrier aircraft was at 12,000 ft., 140 miles from the transmitter.

Ground Mandrel - was a 65-160mc jammer for radar using 24 noise modulated ransmitteers in groups of 6 at 4 sites.

Jostle 1V (RAF designation) - ARI 5289 was a high power FM.CW jammer in 3-6, 6-12. 12-18, 26-35, 35-34 and 45-54 mc bands. The transmitter was a T1524 and with its power unit was housed in a pressurized casing, cooled with a heat exchanger/air scoop. It weighed 600 pounds and was carried vertically in the bomb bay of a B17 or B24. Antennas were a trailing or mast antenna.

Mandrel 1 - a jammer for 68-78, 128-148mc bands. It used a T1408 transmitter, Type 68 modulator, a type 300 power unit (1.2 kw at 80 volts).

Mandrel 111 - was a spot jammer for radars 148-196mc. A TR1657 transmitter/receiver was used.

Pipe Rack - was American designed to jam radars 95-210mc. An aircraft installation used two to six AN/APT-1 transmitters. Wing mounted whips were used.

Tinsel - was a system to disrupt R/T control in the 3-6mc band. It appears rather crude but it used a microphone attached to the engine nacelle, thence to a Marconi T1153 transmitter. A found signal had the transmitter tuned to it, turned on and flooding the signal with engine noise. Not surprisingly, the vibration broke up the carbon mics and eventually the electro magnetic mic was used and the microphone brought inside the air frame.

Window - was a metallic foil strip produced in various sizes and dropped from aircraft to "spoof" enemy radar operators. Window covered the 70-600mc in various sizes but 12"x1/8" was the average size.

Jackal - The famous SCR522 was added to the repertoire of jamming signals against the enemy net. Sixty SCR522 transmitters were installed in B24 aircraft and in sorties over the enemy front line orbited for up to four hours transmitting jamming signals. An Hallicrafters S-27(BC-787) search receiver was used by one aircraft to monitor the effectiveness of the jamming.

Silver - was a device to jam GCI and GL radars in the 53 cm band. It was essentially a R3003AMk22 IFF set modified to produce a squittering signal over the 24-26mc band.

Homing/Warning Devices
- were used to give a bearing on a transmitter and warn crews of the presence of other aircraft. British devices were mostly intended to counter the interceptors, while German devices were designed to bring the interceptor into contact with the bomber. German engineers pursued infra-red detection methods long after developments in this field had been abandoned.

Boozer - gave bomber crews notice when other aircraft were being "painted" by Wurzberg radar. Equipment included Type 164 receivers, Type 65 and later receivers to cover 490, and 530-650mc. Type 177 or 181 indicator were typical at UHF.

Monica - was an active tail-warning device used against interceptors. It was produced in many sub-variants, using ASV11 receivers and ASU MK11 indicator.

Perfectos - was designed to trigger the enemy's IFF set and then provide a bearing on the transmission.

Airborne Interception Radar,
- The Mk X was an SCR-720 and was used first by the RAF in 1943, after being developed in the U.S. by M.I.T. The transmitting antenna was mounted in a frame facing a parabolic reflector rotating at 350 rpm. Range, azimuth or azimuth and elevation could be displayed. The A.I.R. Mk XV (U.S. AN/APS-4ASH) had a frequency in the range of 10gc. The range was 4 miles maximum and 250 ft minimum and weighed 180 pounds. It could see 75 degrees right and left of centre and in elevation 30 degrees above and below it.

References:
"Confound and Destroy:(1978) by Martin Streetly is recommended
reading. Over 100 other references are included in his bibliography.
American documents include APO 557 (Mission record of 803rd/36 Bombardment squadron and CO-AN 08-20-4 (AN/APS-4).
Most of the equipment mentioned is preserved in the Science Museum, London.

Compiled by Pete. D. Williams VK3IZ
<jupeter@net-tech. com.au>

***********************************************