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Intercepting messages before 1st July 1916


bmac
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In the light of the infamous intercepted message by the German Moritz Station at La Boisselle which alerted them the night before to the imminent attack I was interested to read this entry in the 31st Division's War Diary for 30th June when giving units codes to indicate they had arrived at their assembly positions:

"Remember Germans can hear what is telephoned or buzzed"

One wonders how widely this was known and, it it was widely known, what on earth were people in III Corps doing sending such messages 'in clear'? And if it wasn't widely known why not?

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I did some research on this for a documentary series back in 1994. It was possible to identify the officer responsible using 34 Div sources. After careful discussion we decided it would have been unfair to name him (though his name has appeared in print).

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I wonder how widely the actual physics of how a telephone or buzzer worked was known? Unless it was demonstrated, it would not be obvious how easy it was to listen in. Most people would assume that a wire tap was needed. A man talking from a rear position to a forward position would assume it was safe. No chance of the Germans tapping his line. Perhaps this was an example of lack of training.

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Generalleutnant von Soden, Commander 26th Res Div until late 1916 has a number of interesting things to say in the divisional history about interception of telephone calls along his front. At the end of 1915, he reported: ' A new feature was listening in, exploiting earth return systems by means of 'Moritz' and 'Arend' stations. As long as the enemy did not realise what was happening, we were in a position to listen in to every enemy order and we got to know every company commander by name.' By June 1916, he noted, 'Greater care over the use of the telephone by our opponents, because of 'something which must be kept secret.' This made interception much harder.'

Once the bombardment began and other signs of an imminent offensive began to multiply, the intercept stations could not be risked forward any more - presumably to avoid their loss. '...absolute clarity was obtained about the enemy opposite. This was all the more important because the Moritz stations could no longer operate in the front line and had to be withdrawn.'

Nevertheless, as we know, not all of them were withdrawn and a careless slip was made. How critical it was in the great scheme of things I am not sure. Information from deserters and prisoners, not to mention premature blowing of mines was probably at least as important in alerting the garrisons on 1 July 1916 - and they only needed enough time to mount their stairs with their weapons and ammunition.

Jack

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Various sources (including a history of the Canadian signalers) indicate that the German ability to intercept most messages was known from summer 1915 but it was not until in 1916 Sergeant Lorne Hicks of the Canadian army discovered the effect that the Moritz stations were using that the how was known. That it was not a physical tap must have been obvious. Given the area where British efforts on intercepting German signals was initially concentrated it may have been thought to be a magnetic effect from the hand sets and buzzers. It seems that despite this getting the idea of good phone and telegraph practice inculcated into the British forces proved remarkably difficult.

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Once the bombardment began and other signs of an imminent offensive began to multiply, the intercept stations could not be risked forward any more - presumably to avoid their loss. '...absolute clarity was obtained about the enemy opposite. This was all the more important because the Moritz stations could no longer operate in the front line and had to be withdrawn.'

Nevertheless, as we know, not all of them were withdrawn and a careless slip was made.

Some Moritz stations were located in underground saps running towards the British trenches and these may have remained manned even during a barrage

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I agree that interception without an actual tap was known about but I was wondering how widely it was known. Would it be specifically taught to all officers that all phone and buzzer messages within a certain distance of the German lines were at risk or was it a vaguer, 'mind what you say' type of warning.

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The Military Communications and Electronics Musuem at Kingston Ontario puts it this way "Unit identities, names of officers, locations and timings became prohibited subjects for electronic transmission, backed up by court-martial action against offenders." Easy to say but difficult to police but certainly more than a vague warning.

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Thanks Centurion. I assume this was before 1/7/16 so it does rather look as if the officer was culpable.

It would seem so - the restrictions were said to be in place before the discovery of the Moritz monitoring in mid 1916. I did some work looking at the subject some years ago and it seems that British telegraph and phone discipline remained too sloppy right up to the end of the war. The introduction of the Fullerphone helped to greatly nullify the Moriz stations (and even direct taps as a form of scrambling could be applied) but not 100% and so introduced a slightly false sense of security. A similar effect happened in WW2 when German forces confident that Enigma could not be cracked were quite lax about what was transmitted.

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A (perhaps 'the') Moritz station was discovered at La Boisselle when it fell when the RE were investigating the German mining galleries. It contained the transcripts of lots of British messages which were forwarded on to higher authority. I wonder if anyone was court-martialled on the basis of this 'evidence'? Naive, inexperienced, ill-informed or just downright sloppy?

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what on earth were people in III Corps doing sending such messages 'in clear'?

Given the technology of the day there may not have been much choice. Scrambling devices appear to have originated with the Fullerphone which was not in use at the time (and initially only morse could be scrambled). Morse could have course been encoded but this would mean that the message would first have to be coded before transmission and then decoded on reception. In a tactical environment this takes time and slows down and clogs up any signaling system (and can create errors and misunderstandings through miscoding or decoding). Moreover given that code books would have to be supplied to every trench any code would be unlikely to remain secure for very long. One problem in a tactical situation is that you have to code all messages as simply coding only important ones provides information anyway ("They've just sent a message in code - an attack may be imminent")

Voice would have to be in clear hence the need for good discipline and the use of codewords agreed (and distributed by runner) shortly before the event. Even then the enemy would be able to deduce much from the fact that codewords are being used in the first place. "Unit identities, names of officers, locations and timings became prohibited subjects for electronic transmission" appears to have meant 'even using code words'. This can lead to a dilemma as runners may not always be able to get through with messages in time.

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Secure signalling requires well trained signallers and officers. It needs a discipline which is engrained and second nature. I doubt if the attrition in officers and signallers in the Great War allowed this. I believe that the most( only) successful means of maintaining phone security was not to provide them in the front lines at all. There was an ongoing battle even at very high levels between operators trying to impose security and officers wishing to use phones. It was not unknown for operators to be threatened with charges of insubordination when trying to have what were obviously sensitive details sent in code. No signaller will have any difficulty in recognising the scenario.

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Interestingly, given the above comments, the 31st Division used code phrases which sounded as if they made military sense but actually meant the troops had arrived in the assembly trenches. The full entry in the War Diary reads:

Reports will be sent to Divisional HQ when march positions of assembly is complete. The following code will be used:

92nd Brigade – Join Brigade at Bus

93rd Brigade – Rations at Sarton

94th Brigade – Halt at Marieux

Pioneers – Return tomorrow

Company RE – Am returning trucks

Remember Germans can hear what is telephoned or buzzed.

Sadly didn't do them much good!

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Odd choices - all the 'messages' with one exception would sound perfectly reasonable if sent from HQ to the brigades but not as a signal from the brigade to HQ as they are effectively disguised as instructions.

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I don't believe the direction of the intercept would be known.

Modern(ish) procedures included codes for day to day activities which were time expiring. That is they were expected to take about a day to decode. Codes changed every day so no benefit to enemy except in long term analysis. Nowadays with computers available I am not sure if a code that is easy to apply would last 24 hours. The main trouble encountered by operators in their dealings with senior staff was in a battle. Staff officers naturally wished to respond to urgent appeals with equally urgent replies and resented the time it took to encipher instructions. There is a false sense of security in talking to a phone which is not evident when talking to a radio even with an identical handset. As I said, it was mainly a question of education and if the higher staff were sticky, it was hard to blame some captain in the line for a breach of voice procedure.

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The French had developed the ability to listen to the German field telegraph and phones using very similar methods by August 1915. As a result the French realised how the Germans were able to listen to their phones and in 1916 removed all ground return equipment from within three kilometers of the front line replacing it with two way twisted cable based equipment. However they don't appear to have shared their knowledge with their British allies.

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I have come to this thread late and despite knowing a lot about WW1 have not hear of the Moritz station at La Boisselle. I Wikied both main words and am still none the wiser. Would you be so kind to tell me how it worked please, many thanks

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I have come to this thread late and despite knowing a lot about WW1 have not hear of the Moritz station at La Boisselle. I Wikied both main words and am still none the wiser. Would you be so kind to tell me how it worked please, many thanks

Something I wrote elsewhere

'The trench telephone and telegraph system on either side was not secure or reliable.

However the British began to get a sense that their calls were being intercepted with alarming ease. This was serious as the enemy might, for example, gain advance warning of a trench raid or learn when the line was thinly manned. However no one could work out why this was so. It became the common practice not to pass any important information by the trench phones but to rely on despatch riders and runners even with the risk of additional casualties to the messengers. At the same time emergency signalling methods such as warning rockets were kept handy as, with the predictably malignity of inanimate objects, the trench phone would fail just when a call for help was needed.

The cause of the security problem was found by accident when a signals instructor, Sgt Lorne Hicks, on a course in Canada found that his phone was picking up the signal of the man next to him. The British field telephone relied on a ground return system. In this the phones are connected by a single wire with the 'second wire' of the circuit being a short wire to a spike in the ground. The AC current on the phones was creating a signal through the ground that could be picked upon devices known as Moritz Stations. It was worse (easier to pick up) when the phone was being used to transmit Morse buzzes (as was the case over long lines). As the Germans perfected the sensitivity of the Moritz Stations they could 'bug' a phone from a kilometre away. Moreover, as the signal was transmitted through the ground, by creating underground saps towards the British lines they could sit at its end and pick up even more signals. One interesting sidelight to this is that the German monitors frequently picked up a whistling noise that sounded like the screech of a descending shell. Known as 'screamers' these were at one time thought to be artificial noises made by British operators attempting to 'jam' the interception; they are now known to have been created by the solar wind hitting the ionosphere – true signals from outer space.'

I don't know the exact configuration of the Moritz stations but they seem to have been very sensitive receivers coupled with valve based amplifiers (probably the first of their kind). That is certainly the type of equipment the French adopted to intercept German messages

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I take it then that these stations were used along the whole length of the line? Has anybody ever made an asesment of how useful this was to the Germans at the tactical and strategic levels (i.e. in countering trench raids or major offensives) and do we have any evidence that specific raids were compromised as a result of intercepts.

This is the first I've heard of this system, I'd always assumed phones lines would have been 'un-tappable'. You would have thought it would have been more widely known about too as it surely influenced the way the German's conducted operations.

Greg

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Using a Ground-Return process, surely the effectiveness of the equipment, and thus the ability to be listened into, would be affected by the moisture content of the ground.

Electromagnetic signals are at extremely low levels (a low voltage would have been used) and an aerial type device would have been needed, not a spike in the ground. It could be an earth point for the equipment but not an Radio Frequency (RF) Detector. Consider how a ferrite rod antenna works in today's portable radios, same principle. The transmitted energy "cuts the winding" on the ferrite rod and a signal level of a few micro-amps (millionths of an amp) is created which is then amplified and processed within the circuitry.

I admit that the equipment would have rather "agricultural" based on todays standards as the transformers and inductors would have been very chunky and without shielding. But the low voltage means that it will be rather low power. Whilst the current consumption would have been available via batteries but it could not be excessive as the batteries would have always run flat, and fast. Therefore, low current and low voltage equals low power.

Therefore, I suspect that the Germans were detecting a "leakage" type effect via the damp/wet soil. On an Ground Return process, the signal (energy) from the sender to the receiver would not travel like an arrow fired from a bow but would radiate out from the ground spike in a 360 degree fashion. If the enemy had equipment that was sensitive enough, then they would become the unintended receipient of the signals. I heard a story that the Germans could hear a background buzzing noise in their existing equipment at Fromelles (and possibly before) and that they then developed high sensitivity equipment believing that it may be the British telephone traffic. They were correct.

An insulated twin wire system presents no leakage into the ground. But then, how careful were they with the quality and condition of the wire's insulation during the rest of the War. Also, consider that a twin wire system still produces an electromagnetic field.

Hope I havn't confused you all with this technical stuff. I was only trying to help.

Regards, Peter

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It would not have helped that the British Buzzer and phone system was described and illustrated in the 1911 (?year) Encyclopedia Britannica. Tom is correct in saying that what was required was disciplined and well trained officers and signallers, but forward of the RE signallers in the battalions was where the problem was and I believe at that time in 1914-1916 there was no formal "radio telephone procedure".

As to identifying who was a HQ and who was a subordinate/sub unit, fairly simple traffic analysis by the Germans would have very quickly established that; who initiates the call; who receives/makes the most calls; who is the deference shown to, and so on.

Codes and cyphers are a whole additional subject, but suffice to say I don't believe formally issued and daily/weekly changing codes were used down at the brigade and battalion level at that stage, the production, printing, management and security of such material was a very big operation, probably beyond the ability of the RE Signal Service at that time (noting that the Int Corps also had a large part of that responsibility until WW2). Codewords as distinct from codes were usually made by the writer of the orders and as Centurion pointed out, they should be innocuous words.

Despite all of this, telephone discipline and communications security may seem sensible and commonsense, but even in 1941 the British Army wasn't noted for it, the Eighth Army got a rude shock after the capture of the Afrika Korps 621 Signals Company, its signals intelligence unit. And as an ex-Regimental Signaller I can say that even much later with the public knowledge of Enigma and so forth many users weren't much better!

Cheers,

Hendo

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Peter, you are correct about the soil and moisture content, when I did my Regt Sig training we never got much distance with Earth circuits here in Australia because of the hydrology and soil types, when it rained the range increase was noticeable, I dare say the better soils of Europe provided greater range. We did know that the signal could be "focused" by not spreading the wires from the ground spike 360 degrees, but keeping them pointing in the direction of transmission, the same applied for short range HF radio. As for the power issue the "buzzer" like a morse key would result in a sharper power burst at higher power and therefore greater (quite significantly) range than making a voice telephone call.

Cheers,

Hendo

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