Radio Finger Printing (RFP)

[Fatboy Coxy]

Reading through Peter Elphick's book, Far Eastern File, I came across the details of Radio Finger Printing (RFP), on pages 156-157. I have copied the piece because I would like to know if anyone else is familiar with this, or could add more.

"Positive identification of ship call-signs were made, and from early 1941 were confirmed by use of 'radio finger printing', or RFP equipment, This was an ultra-secret technique using a very high-speed cine-camera with specially sensitive film. It was the invention of Professor (later Sir) Alistair Hardy of zoology and oceanography fame, who was sent out from England to instruct operators at Kranji in its use. The camera was designed to film visual presentations of wireless transmissions as presented on a cathode-ray tube, Examination of the film not only allowed the design of the transmitter to be determined, but microscopic examination of the split-second of film as the transmitter operator pressed his key, allowing the actual transmitter itself to be identified. By the middle of 1941 FECB had what was virtually a dictionary of transmissions of radio sets aboard major Japanese ships. This meant that ships could be identified without the necessity of identifying their call-signs which might be changed from time to time. At Kranji in 1941 the RFP system was under the charge of Captain J.W. McClelland who headed the steadily growing D/F network and who promulgated a daily summary of ship positions."

I'm half expecting this technology to be known in the US under a different name, and no doubt will kick myself when told.

[wadinga]

Hi Fatboy,

This is a very interesting method of regularizing something which was previously more instinctive. Thanks for posting this. Morse key telegraphists had from the earliest days discovered they could recognise other operators by their "fist". That is the idiosyncratic way they actually operated the key. Slight hesitations over certain letters, length of word gaps, transmitting familiar phrases faster or slower etc. This was done in real time, listening through headphones and obviously required a lot of experience and familiarity with the styles of the particular operators. Wireless telegraphy had the same characteristics.

The "Y" service D/F station operators, listening in on German radio transmissions and sending the Enigma-encoded gobbledegook to Bletchley Park, were often able to identify individual operators by the their "fist" and send this additional evidence in to assist the analysis.

Although the "Neptun" cypher used by Bismarck during her first and only mission was at the highest level and used so infrequently that it could not be broken, "Y" service operators were able to determine from RFP which were her transmissions and thus confirm that the series of D/F positions derived were from that ship.

This technique with film presumably not only records the transmission allowing re-examination, but allows additional analysis like the rise and decay times of every dot and dash to be recognised and related to particular transmitter equipment as well as the individual operator on the key. Later, when fast burst transmissions of mechanically-generated Morse were used, I expect it would be even more useful.

I've no idea what the US forces would call it.

All the best

wadinga

[OpanaPointer]

I've no idea what the US forces would call it.

All the best

wadinga

Something involving prostitutes and San Miguel beer, I suspect.

[Michael L]

Greetings.
For what it is worth, today in Naval circles they talk about the 'acoustic signature of the submarines'. Something that was highlighted in Tom Clancy's 'The Hunt for Red October'.
Of course, the use of hydroponic detection equipment dates back to the First World War.
In the lead up to the Battle of the Denmark Strait, 24 May 1941, the hydrophone operators aboard the KMS Prinz Eugen detected and reported a pair of fast moving turbine ships approaching, some 30 minutes before the lookouts spotted them.
IIRC, a good operator could distinguish the class of ship - e.g. destroyer, cruiser, battleship.
Cheers, Michael L.

[Byron Angel]

Reading through Peter Elphick's book, Far Eastern File, I came across the details of Radio Finger Printing (RFP), on pages 156-157. I have copied the piece because I would like to know if anyone else is familiar with this, or could add more.

"Positive identification of ship call-signs were made, and from early 1941 were confirmed by use of 'radio finger printing', or RFP equipment, This was an ultra-secret technique using a very high-speed cine-camera with specially sensitive film. It was the invention of Professor (later Sir) Alistair Hardy of zoology and oceanography fame, who was sent out from England to instruct operators at Kranji in its use. The camera was designed to film visual presentations of wireless transmissions as presented on a cathode-ray tube, Examination of the film not only allowed the design of the transmitter to be determined, but microscopic examination of the split-second of film as the transmitter operator pressed his key, allowing the actual transmitter itself to be identified. By the middle of 1941 FECB had what was virtually a dictionary of transmissions of radio sets aboard major Japanese ships. This meant that ships could be identified without the necessity of identifying their call-signs which might be changed from time to time. At Kranji in 1941 the RFP system was under the charge of Captain J.W. McClelland who headed the steadily growing D/F network and who promulgated a daily summary of ship positions."

I'm half expecting this technology to be known in the US under a different name, and no doubt will kick myself when told.

It is always a very good day when I learn something about which I had never previously been aware.
Thank you, sir!

Byron

[marcelo_malara]

I was told by a pilot of Grumman Tracker during Malvinas/Falklands war, that onboard they have installed an oscilloscope to graph the radar signals of the RN ships, and that the form of the signal was taken by an instant Polaroid camera to have it filed for future identification.

Regards

[Steve Crandell]

I was told by a pilot of Grumman Tracker during Malvinas/Falklands war, that onboard they have installed an oscilloscope to graph the radar signals of the RN ships, and that the form of the signal was taken by an instant Polaroid camera to have it filed for future identification.

Regards

When I served in the USN our submarines carried a substantial amount of equipment dedicated to collecting and analyzing all kinds of electromagnetic emissions. A modern submarine periscope is a complex antenna capable of receiving and amplifying pretty much the entire spectrum and passing it on to the different types of equipment aboard for it's analysis.

Ships and aircraft likewise, although I believe submarines gave it greater importance in their operations, at least in part because the target probably wasn't aware that you were in the area.

[Fatboy Coxy]

Found a good article on it and TINA, see http://jproc.ca/rrp/rfp_tina.html