Don't forget the Digikey !! -------------------------------------------- On Wed, 6/22/16, Richard W. Solomon <w1ksz@earthlink.net> wrote: Subject: Re: [time-nuts] Measuring receiver... To: "'Discussion of precise time and frequency measurement'" <time-nuts@febo.com> Date: Wednesday, June 22, 2016, 9:20 AM Back before Iambic Paddles and Computer Keyers, the Vibroplex Bug (or some copy cat version) was the key of choice. You could ID Operators by what they called ..."swing"... , the spacing between Dots and Dashes. 73, Dick, W1KSZ -----Original Message----- From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of William H. Fite Sent: Wednesday, June 22, 2016 6:54 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Measuring receiver... I was a newbie at the very tail end of commercial telegraphy but the old guys spoke of operators who "sent with an accent" and one apparently memorable employee who "stammered." On Wednesday, June 22, 2016, Bob Camp <kb8tq@n1k.org> wrote: > Hi > > Based on what I have read, at least at the start of WWII, the > recognition was all done by ear. The operator rather than the > transmitter was the key. The gear to do much else simply was not out > in the field. > > Bob > > > > On Jun 21, 2016, at 9:01 PM, William H. Fite <omniryx@gmail.com > <javascript:;>> wrote: > > > > In the days of my misspent youth, I worked as a telegrapher (one of > > the very last) for a Norwegian shipping line. We sent and received > > both Norwegian and English though few of us were bilingual. Between > > ships and shore stations, there were about forty of us and we all > > could recognize each other's "fists" with near-perfect accuracy. > > This is not difficult, gentlemen, and does not require any esoteric signal analysis. > Transmitters > > would be a different story. > > > > Bill KJ4SLP > > > > > > > > On Tuesday, June 21, 2016, John Ackermann N8UR <jra@febo.com > <javascript:;>> wrote: > > > >> I've seen references that at least by the latter part of WW2 > oscillographs > >> were being used to identify transmitters and/or ops.  It should be > possible > >> to deduce chirp, rise time, fall time of signals, all of which > characterize > >> the transmitter, as well as element spacing and other > >> characteristics > that > >> help identify the operator, from oscilloscope snapshots of the > demodulated > >> audio at various sweep speeds. > >> > >> > >>> On Jun 21, 2016, at 7:02 PM, Alan Melia <alan.melia@btinternet.com > <javascript:;> > >> <javascript:;>> wrote: > >>> > >>> TX "fingerprinting" in WWII > >>> You seem to be forgetting that there were very few of the > >>> sophisticated > >> digital timing systems were available 75 years ago. Traffic > >> analysis was started early in 1938 or even before. By 1939 we knew > >> all the nets used > in > >> Europe and had "Y" ( a corruption of WI, Wireless Intercept > >> )operators monitoring the nets. Many of these were amateurs and > >> they were > allocated to > >> specific nets and followed them around as they moved. They became > >> very familiar with the "accents" of operators on their nets, and > >> particularly before 1939 security procedures were very lax and "chatting" > >> common-place.....but it was all aural. > >>> > >>> I suspect serious transmitter parameter logging was not done > >>> before the > >> cold war when spectrum analysers, or at least pan-adapters became > >> more readily available. To keep a little OnTopic .....you would > >> have > difficulty > >> doing this with a BC-221.!! :-)) A crystal clock of this period was > >> at least one fully utilised 6foot 19inch rack (there is one at > >> Grenwich.) > >>> Alan > >>> G3NYK > >>> > >>> > >>> Alan > >>> G3NYK > >>> > >>> ----- Original Message ----- From: "jimlux" <jimlux@earthlink.net > <javascript:;> > >> <javascript:;>> > >>> To: <time-nuts@febo.com <javascript:;> <javascript:;>> > >>> Sent: Tuesday, June 21, 2016 10:02 PM > >>> Subject: Re: [time-nuts] Measuring receiver... > >>> > >>> > >>>>> On 6/21/16 11:28 AM, Brooke Clarke wrote: > >>>>> 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? > >>>> For "human controlled" stuff, e.g. recognizing someone's "fist", > >> there's a huge literature out there on biometric identification > >> looking > at > >> things like keyboard and mouse click timing - the timing > >> requirements > are > >> pretty slack, and hardly time-nuts level, unless you're looking to > >> do it with mechanical devices constructed from spare twigs and > >> strands of > kelp. > >>>> > >>>> There have been a variety of schemes for recognizing individual > >>>> radios > >> by looking at the frequency vs time as they start up. Likewise, > >> it's > pretty > >> easy to distinguish radar magnetrons from each other.  Not a lot of > papers > >> about this, but you'll see it in advertising literature, or > occasionally in > >> conference pubs (although I can't think of any off hand).  There > >> was someone selling a repeater access control system that was based > >> on the transmitter fingerprint. > >>>> > >>>> But the real reason why you don't see any publications is that > >>>> this > >> stuff is pretty classic signals intelligence (SIGINT or MASINT) and > >> it > is > >> still being used, and is all classified. You're not relying on > >> Betty the receiver operator to recognize the characteristic chirp > >> as the agent's radio is keyed, it's all done by computer now, but > >> the basic idea is the same.  And as with most of this stuff, the > >> basics are well known, but > the > >> practical details are not, or, at least, are the proprietary secret > sauce > >> in any practical system. (In a significant understatement, Dixon, > >> in "Spread Spectrum Systems" makes some comment about how synch > acquisition is > >> the difficult part and won't be described in the book) > >>>> > >>>> You might look at the unclassified proceedings of conferences > >>>> like > >> MILCOM and find something.  Googling with MASINT might also help. > >>>> > >>>> _______________________________________________ > >>>> time-nuts mailing list -- time-nuts@febo.com <javascript:;> > <javascript:;> > >>>> To unsubscribe, go to > >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >>>> and follow the instructions there. > >>> > >>> _______________________________________________ > >>> time-nuts mailing list -- time-nuts@febo.com <javascript:;> > <javascript:;> > >>> To unsubscribe, go to > >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >>> and follow the instructions there. > >> > >> _______________________________________________ > >> time-nuts mailing list -- time-nuts@febo.com <javascript:;> > <javascript:;> > >> To unsubscribe, go to > >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >> and follow the instructions there. > >> > > > > > > -- > > I am Pulse. Unbreakable. > > _______________________________________________ > > time-nuts mailing list -- time-nuts@febo.com <javascript:;> To > > unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com <javascript:;> To > unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- I am Pulse. Unbreakable. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.