Hi:
During W.W.II there were secret methods of "fingerprinting" radio transmitters
and separately the operators.
I suspect the transmitter fingerprinting involved things like frequency accuracy, stability, CW rise and decay time,
&Etc. For the operator some from of statistics on the timings associated with sending Morse Code. But. . . I haven't
seen any papers describing this. Can anyone point me to a paper on this?
--
Have Fun,
Brooke Clarke, N6GCE
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
The lesser of evils is still evil.
-------- Original Message --------
Nick,
Welcome to the world of FMT-Nuttery where we strive to make absurdly accurate
off-air frequency measurements.
I regularly participate in the FMT's. The "measuring receiver" I use is a HP-3586B "Selective Level Meter". While
the 3586 series of receivers will only give you 0.1 Hz resolution, there are simple methods to use them to get down to
1 mHz (milliHertz) resolution, or better. You'll quickly find out that you're limited by propagation between the FMT
transmitter and your receive location.
Rather than go into a long dissertation here on how to do this, here's a link to the write-up for my preferred FMT
Methodology - K6OQK FMT Methodology.
See: http://www.k5cm.com/k6oqk%20fmt%20new.htm
You're probably already familiar with Connie, K5CM's website for all things FMT, but in case you're not, take a look
at: www.k5cm.com
I'll be glad to answer any questions you have. You can either ask here or send
me a direct e-mail at: b...@att.net.
Burt, K6OQK
From: Nick Sayer <nsa...@kfu.com>
I'm considering taking a shot at the next ARRL frequency measurement contest.
The assumption going in is that the signal is CW, with at least a half minute or so of just solid "on" at one point or
another and that reception is reasonably good.
I've got a good TIA and excellent references, but that's the easy part, it seems to me. It seems to me that what I
really need to do is make a synthesized heterodyne receiver that can present an accurately tuned RF band pass - say,
10 kHz wide with the synthesizer set for
5 kHz steps - to the TIA, with some manually tunable high-pass and low-pass filtering to isolate the signal of
interest. If the mixer got its LO from a synthesizer with a GPSDO reference, it seems to me that you could then
measure the frequency of the signal of interest (now an audio frequency, so you can listen to it too) with the TIA
(also getting the GPSDO reference) and then do simple math to arrive at the actual RF frequency.
Anybody have any thoughts?
Burt I. Weiner Associates
Broadcast Technical Services
Glendale, California U.S.A.
b...@att.net
www.biwa.cc
K6OQK
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