The Wireless War Comes to America

On Yanks and Y stations

According to the headline on the afternoon edition of the Providence Journal, 29 April 1915, the German embassy was about to warn passengers against sailing on the Lusitania. The very next day, Count Johann Heinrich Graf von Bernstorff, Germany’s ambassador to the United States, put an advertisement in American newspapers warning passengers not to sail on the Lusitania. How did they get this scoop? According to its owner and editor, the newspaper’s radio station operator had overheard an unencoded transmission from the Foreign Office in Berlin to the Telefunken station on Long Island, seen above, and a reporter was able to discern its hidden meaning by reference to a copy of the latest World Almanac.

Of course, this story was false. John Revelstoke Rathom, the aforementioned owner and editor of the Providence Journal, was the assumed name of an Australian-born British agent and serial fabulist. Possibly born John Solomon, he was laundering real intelligence from Room 40 in London. It was one of many incidents in which the British hoped to manipulate the neutral United States into openly taking their side.

A later, more successful example was the so-called Zimmerman telegram, another diplomatic transmission that Room 40 intercepted, decoded, and passed on to the Wilson administration — but only after carefully arranging a cover story and misleading the president about the origin of the information. Room 40 did not want the Germans to know that their communications were completely compromised.

After Berlin adopted new coding systems in 1916, poor staff work led to many stations being without their new codebooks on the appointed day, and so the traffic would be sent in both old and new codes, allowing easy decryption. New codes that did arrive unbroken were routinely cracked before the end of the shift. German cryptology was nowhere near as advanced, nor did they ever create a systematic, strategic approach to enemy signals on the order of Room 40. Centralization efficiency was a key advantage for Britain, a thing far too important to risk through public disclosure.

However, we must credit the Germans for their own creative uses of wireless transmission. In the age of Marconi, news traveled by both wire and radio, with outlets paying subscription fees to republish it. Seeing an opportunity to circumvent the blockade on their news wire services, the Germans began transmitting their war news free of charge. Not only did their stories reach newspaper readers around the world, they were often unattributed, making it impossible for the news consumer to discern the origin of the “news.” Each side tried to shape the information environment of Americans; the British were simply better at it.

Not only did they have the advantage of speaking the language, they made their own advantages in communication. Britain’s very first act of war, carried out at the behest of Winston Churchill before the ink on Parliament’s declaration was even dry, was to cut Germany’s undersea cables. This forced Berlin to rely on the Telefunken station for communications with the Americas, which in turn allowed Room 40 and the Foreign Office to exploit those communications against Germany, particularly in the United States.

Of course, it was the return of unrestricted u-boat warfare that finally pushed Congress over the edge. Nevertheless, the fusion of secret activities — radio SIGINT and propaganda — had created information dominance. Germany lost any narrative control in the United States well before 1917, and then Americans were telling themselves a story that London had written for them. So it is ironic that when the Yanks arrived in France as radio war neophytes, they learned most of their lessons in these black arts from the French instead of the British.

According to John Manley, an Alabama-born US Army signals intelligence soldier in the AEF, two working offices were set up and working within the intelligence branch by the end of 1917. The Radio Intelligence Section came from the Signal Corps, while men with math skills were recruited from other corps, such as artillery, to the Code and Cipher Section under Herbert Yardley. Although there were doubts about the value of SIGINT among the officer corps, Gen. Dennis Nolan — the G2, or intelligence officer to Black Jack Pershing himself — had been briefed on British success at tracking the German order of battle through radio signals, and convinced Pershing of its value. He would not be disappointed.

Despite misgivings from Hindenburg, who appreciated the dangers of wireless communication better than anyone, the German army had to rely more on radio after 1916 because of its obvious advantages over communication wires that were exposed to shrapnel and high explosive blast. Aircraft routinely flew with wireless sets by 1916, and by 1917 pilots were using voice radios to communicate with the ground and even coordinate during dogfights, but none of this new signal was encrypted.

German Morse security practices had improved, but they were still making too many mistakes. Their radio deception efforts could be screened out by cross-referencing location information with callsigns. In July of 1918, Germany had 25 standing weather stations sending out seven reports a day, all using the same format that never changed. More to the point, at the outbreak of the war, the French Bureau du chiffre had mastered the art of cracking new German cipher systems in less than a day. With almost a million words already decrypted, France had much to teach the Americans about radio battle with Germans.

Working with Georges Painvin, a graduate of the Ecole Polytechnique, Manley learned how to crack the German cipher systems when they changed. AEF troops were creative — they invented the motorized radio SIGINT vehicle on their own in 1918 — but there was little time for a learning curve, so they paid attention to their lessons. Like the American Expeditionary Force itself, they had to learn fast. It was a mark of their tutelage that the Yanks adopted the French phrase chut, j’ecoute (“shh, I’m listening”) as their motto.

According to the website of the National Museum of the United States Army, more than five hundred Americans were employed in collecting, decrypting, and analyzing German traffic. Not only were they monitoring ground stations, they were learning to fight a whole new kind of war in three dimensions. Tracking aircraft signals at special “aero stations,” the French had already begun vectoring their own aircraft to intercept enemy flights, anticipating radar by two decades. Further careful observation of which German pilot callsigns gave the most effective artillery fire direction, and which ones seemed less aggressive, allowed the French to concentrate their counterbattery fire against the German guns that were being directed by the more heroic pilots, which they targeted with swarms of fighters.

Now the French showed the Americans how they had learned to prosecute the air war on the airwaves. One neat trick, deployed to great effect in 1918, was to box single German wireless stations within intense barrages of artillery fire during the transition period when the new codebooks were being delivered, forcing the higher stations to send messages in both the new and old code for a day, immediately compromising the new cipher key. Jamming could be used the same way, and it had the most effect once it was turned off. Contrary to Jeremy Bentham’s theory of the panopticon, German radio operators often assumed they were no longer being surveilled, and relaxed their guard, once the signal noise stopped, a phenomenon this writer has experienced in live training environments. Col. Frank Moorman, who set up the US Army’s SIGINT operation, recalled that it was right after one such episode in 1918 that Corporal Painvin, now attached to the AEF, decrypted the transmission which led to the breaking of the German army.

The American contribution to the First World War has been deprecated, and by American historians foremost, for its comparative smallness. Late to the war, reliant on material and training assistance from their allies, the United States did not lose anywhere near as many lives as Britain or France. No one disputes that American aid and American numbers surged at just the right time, when Germany was winning the war in the east and turning its strategic focus to the west. Nevertheless, it is fashionable to be dismissive.

Perhaps we could judge the new combatant by the results of their war, and see how they helped the French fight a new kind of war.

When the Germans launched the Ludendorff Offensive, or Kaiserschlacht, in 1918, the French 4th Army and the AEF were ready for them. Warned in advance by their respective intelligence branches based on signal intercepts, Gen. Henri Giraud used a defense-in-depth scheme with small teams at the front and well-timed artillery to disrupt the German attacks. This success was followed up with counterattacks. Then in September, Gen. Pershing relied on radio intelligence for the timing of his offensive at St. Mihiel: “The location of all enemy radio stations in their proper places by means of [direction finding] on the night before the attack was the determining factor in the decision of the Chief of Intelligence that the enemy had not already withdrawn” from the salient. Using their motorized direction finding stations to keep up with the advance, the AEF followed up the resulting success with timely warning of German counterattacks.

Almost everyone expected the war to last until 1919. That it did not — that the German army broke in Ludendorff’s hands, falling back in the great “Hundred Days” that finally ended the war — is testament to the French success in wireless warfare, and the success of their apt pupil.