Hi All, My principal WW2 interest is in radio communications and those "in the know" will recognise my username as a piece of WW2 US Signal Corps equipment. There has been some recent discussion on a military radio-related forum elsewhere of radio deception at the time of the Normandy landings and under Ops Fortitude North and South in particular. I have come across several references to equipment used to simulate radio traffic (both radio telegraphy and radio telephony) of fictitious military formations like Patton's 1st US Army Group and Op Fortitude North seems to be almost wholly radio-based (Op Skye, etc). However, although concise technical manuals for the equipment used are available they give little detail on the actual deployment of this equipment, who used it, where and what it looked like in use. There is also some mystery surrounding the designation of the deception equipment; in the technical data (EMERs) the equipment is designated "S.P.F.", but attempts to guess what this acronym stands for have drawn a blank. One other factor is the dates of the EMERs, mostly 1945 but one of which is 1947, implying possibly that the system went on to be used in later conflicts. SPF used today seems to be for "Special Forces". To quote from the EMER for Wireless Station, S.P.F. Mark 3:- “A number of operators, up to five, in a small studio, are provided with microphones or Morse keys and pass their messages according to a pre-arranged plan. These messages are normally passed through the S.P.F. switch unit, where identifying signals are superimposed, to a wire recorder where they are recorded for future use. When it is desired to broadcast the messages, the recording is played back through the switch unit and the (identifying) signals cause separate channels to be selected for the message from each operator, the modified sender being set up so that there slight differences in carrier frequency and also in the output power on each channel. The system also automatically switches the sender on at the beginning and off at the end. The switching signals are not, of course, radiated”. I'd be very interested to hear from members who can shed some light on S.P.F., even what it stood for would be useful, as an internet acronym search showed no likely "hits". A photo of the actual studio would be fantastic, in fact anything related, however unlikely. Thanks for your time reading this, BC610E
Operation Fortitude THE CLOSED LOOP D-DAY DECEPTION PLAN Hi, Thanks. A quick look through that document shows me that there was a naval aspect to Op Fortitude North and the technical manuals I have do refer to a Naval SPF, although the radio used (Modified Wireless Set No 19) is actually army equipment. Probably the RN didn't have a lot of field radios and took their supplies from the army. The SPF gear I have the most pictorial data on shows that it could simulate up to five stations in a "net" but the above article refers to the radio traffic of an entire army group of 150,000 men. Possibly a encamped group inter-connected by field telephone and teleprinter wouldn't need much radio until it started to move? As I've read elsewhere, the article also mentions that the Germans were apparently not monitoring the Fortitude North traffic as much as the D-Day planners had hoped for due to their monitors being busy with the Russians. Thanks again, BC610E
Hi All, Thanks to Lee Richards of ARCRE I have now have some further info on the "S.P.F." equipment and the organisations involved in developing it. However, annoyingly there is no reference to what the SPF acronym actually means! The file I have obtained is WO 244/153, Design of S.P.F. (Wireless Deception Equipment) and covers 63 pages.[FONT="]It covers a period from mid-1943 until after Op. Fortitude in Sept 1944 and there is a lot of correspondence on sorting out technical problems with the apparatus used to record and replay the spoof traffic, particularly ensuring that the system didn't give the game away by airing control tones, switching clicks, etc. which might make enemy monitors suspicious. Anyway, as is the nature of researching , the new file has raised more questions than it answers so I will no doubt be going back to TNA for more of the same! I also now have the war diaries of 5 Special Wireless Group from Kew but they are post Sept 44 and there is little on SPF other than SPF-modified Wireless Sets 19 being exchanged for unmodified sets, which seem to coincide with 5 Group undertaking more routine comms duties with the WS 26 system until they disbanded in mid 1945. More, if and when I have it, '610 [/FONT]
I believe SPF stands for symmetric polynomial function http://en.wikipedia.org/wiki/Symmetric_polynomial http://www.wordnik.com/words/polynomial Hope the links help explain. If not talk to a mathematician or a radio technician! I'm neither!!
I believe SPF stands for symmetric polynomial function http://en.wikipedia.org/wiki/Symmetric_polynomial http://www.wordnik.com/words/polynomial Hope the links help explain. If not talk to a mathematician or a radio technician! I'm neither!! Hi, Possibly! But maybe more suited to code-breaking? A look around acronym sites with a military bias gives a likely candidate as "Special Purpose Force", and this was a special purpose project. I need to find the 1942 or '43 papers relating to the original requirement for a radio deception system, because probably it was at that point the system was given a name. The later paperwork I have just uses "S.P.F." or "SPF" without elaboration. The original work seems to have been done by the "Light Scout Car Training Unit" who were mainly working on "sonic" deception, that is recorded battle noise like tank engines, etc that could be played to deceive the bad guys. Later SRDE and the GPO got involved. But thanks anyway , '610
Digging through my "archives2 I have found an article I printed some time ago from either the newsletter of the Royal Signals Corps (The Wire) or that of the Royal Signals Association. The last few years of these are available to view online but this extract comes from 2004 and is no-longer available: - Extract from “D Day Deception Plan – Operation Fortitude Royal Signals Involvement – The Battle of The Airwaves By Colonel (retd) Cliff Walters, Museum Director C2004 To simulate the wireless communication of a unit involved monitoring them closely for some time. This was done by No 1 Company of No 5 Wireless Group using specially fitted Lorry Command Vehicles (LCV) which would deploy to the location of the units involved to listen to their wireless traffic, making notes and recordings. The No 19 set was used and the exercises were recorded onto the newly acquired “Recorders, Playback, Wire No 1”. This was new American technology and it recorded onto a thin steel wire about the diameter of a hair. There were about 4 miles of wire on a 4 inch spool which played back for about 1 hour. To make the recordings the LCV was set up with a No 19 wireless, a recorder and six 19 set microphones: one for the control station operator and 5 for outstation operators. The microphones were connected through a sophisticated control box which sent a short “identification current” to the recorder to signify which microphone was being used, Once the recording was completed the wire was handed to a “Playback truck which was equipped with a modified Wireless set No 19, a control box marked “SPF” and a recorder. The origins of the nomenclature SPF are not known but it may have been an abbreviation of “spoof”. The LCV would then deploy to a field location to give the Germans the impression that a real unit was on exercise in Kent. The crew comprised an NCO operator, an instrument mechanic and a driver. Before each message was sent by the No 19 set it would receive the recorder’s “identification curren”t from the SPF box to identify which of the six operators was transmitting a message. Then, before sending the recorded message, the No 19 set would automatically change power and frequency by a slight amount to a predetermined level for each operator. This gave the impression to the Germans that six different wireless sets were intercommunicating
Noel, Thank you for putting up the very interesting extract from the D-Day Deception Plan for Op. Fortitude. I am impressed that this technology existed and no doubt it proved very effective in generating bogus traffic. Regarding Op. Fortitude North I have always been led to understand our major deception ploy was the large-scale exercise directed by 52 Division HQ employing unit officers (I was one!) on 19 WS moving in progressive stages to represent the Division concentrating in areas suitable for embarkation to Norway. Joe Brown
Digging through my "archives2 I have found an article I printed some time ago from either the newsletter of the Royal Signals Corps (The Wire) or that of the Royal Signals Association. The last few years of these are available to view online but this extract comes from 2004 and is no-longer available: - Noel, Thanks for that very interesting quote. It would appear that "SPF" will probably stay a mystery, unless the files relating to the original spec for the system can be located. As I mentioned earlier in the thread, I do have the file on SPF Design and that doesn't explain the term. I think the "Spoof" idea may have merit but does that not go against the protocol that a name should contain nothing that might point to the actual nature of an operation or equipment? There is also "CLH" which apparently was the Naval equivalent of SPF and for which I can find no explanation to. It was used in Op. Fortitude North. Thanks again '610.
Hi All, Have made a little progress with my researches into Fortitude radio deception. Does anyone have info and in particular any photos of the Royal Navy "Radio Deception Units" deployed for Fortitude North? Demounted from their usual transport these units were also part of Op Accumulator when the units deployed to two Canadian destroyers off the Contenin penisula. as a diversion to the main bridgehead. I have the radio scripts for the latter operation. The fact that the RDUs used Army radios (WS 12 and 22) was interesting as it shows that German Y was capable of radio fingerprinting radio sets as being specific to a British service. Any input gratefully received. '610E
Operation FUSAG I wrote an article on how we swa it at the time . Cannot find the damn thing. FUSAG = (First united state army group) It never existed but Hitler thought it did...
Hi All, Have made a little progress with my researches into Fortitude radio deception. Any input gratefully received. '610E You could try Double Cross by Ben MacIntyre. I have the book but have not read it yet. Lots in the index on Fortitude radio etc... EDIT: Checked in index on Amazon, may be 4 pages on radio.
Infantry signallers were trained to always regard the German radio intercept service as super-efficient . We were also alert to reduce wireless transmission time on the air to discourage enemy direction-finding (DF) antenna beaming on your best radio signal strength with a view to tracking your location. It has been suggested that the Germans could do this with an accuracy to less than one degree wrong! Do we now have evidence to back-up this up? Joe Brown
Infantry signallers were trained to always regard the German radio intercept service as super-efficient . We were also alert to reduce wireless transmission time on the air to discourage enemy direction-finding (DF) antenna beaming on your best radio signal strength with a view to tracking your location. It has been suggested that the Germans could do this with an accuracy to less than one degree wrong! Do we now have evidence to back-up this up? Joe Brown Hi Joe, I think the feeling was mutual as a lot of German radio gear had "The Enemy is Listening!" on the front panels. (Obviously in German) I was told on another forum that the German D/F bearing was about one degree but the origin wasn't given. One query I raised was that if the Germans could D/F with that level of accuracy then surely they would detect a British spoof station simulating up to six outstations by the fact that the bearings between those six would not change, as the same antenna was being used on each transmission. Cheers '610E
Introduction page Foundation for German communication and related technologies (translated) Plenty of intelligence (British Intelligence Objectives - Sub Committee) http://www.cdvandt.org/BIOS-551.pdf---------Example Direction finders: http://www.cdvandt.org/Tel-data-E374.pdf
Introduction page Foundation for German communication and related technologies (translated) Plenty of intelligence (British Intelligence Objectives - Sub Committee) http://www.cdvandt.org/BIOS-551.pdf Direction finders: http://www.cdvandt.org/Tel-data-E374.pdf Thanks! The D/F receiver spec seems to match that 1 degree claim, although the model shown is for LF/MF and the bulk of Fortitude traffic would be higher, typically 2 to 5 MHz. Possibly receivers for those higher frequencies would acheive a similar accuracy, although the signals would be more prone to skywave, especially at dawn/dusk, and degraded accuracy. Anyway, we can say that there is a distinct possibility that German Y could detect "spoof" radio nets emanating from one site. '610E
BC610E. The 52 Div exercise conducted and directed by them involving brigades and battalions, in which I took part with 7/9RS, conformed to a specific and timed programme of key messages interspersed with the usual volume of 'domestic' traffic and detailed actual movement of wireless terminals to pre-arranged locations and over-night stops. Clearly, designed to feed enemy radio intercept and direction-finding with data: movement on the ground towards likely ports of embarkation; intent was 52 (Lowland) Division preparing to deliver the anticipated 'left-hook' attack of Norway. Joe Brown.
