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Author Topic: 4107.8 slow dasher  (Read 310 times)

Offline Teotwaki

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4107.8 slow dasher
« on: March 17, 2022, 0547 UTC »
Very strong on KFS SE with a roughly 2 sec on and 7 off pattern
Jim
NRD-525, Elecraft KX3 and Elecraft PX3 Spectrum Display
76' end fed long wire & 66' off-center fed dipole for 10/20/40 meters
Orange County, SoCal, The better half

Offline Teotwaki

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Re: 4107.8 slow dasher
« Reply #1 on: March 17, 2022, 0555 UTC »
Well, I zoomed out a bit and saw a bigger pattern being broadcast so it’s not a new dasher.

I need Windy back on the air dammit  :)
Jim
NRD-525, Elecraft KX3 and Elecraft PX3 Spectrum Display
76' end fed long wire & 66' off-center fed dipole for 10/20/40 meters
Orange County, SoCal, The better half

Offline l0ngwire

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Re: 4107.8 slow dasher
« Reply #2 on: March 17, 2022, 0930 UTC »
Guess this is is is a utility signal of some kind.

On the KFS Omni at 0430z there were two long dashers at 4108 and 4109 going at the same time.  When dashing there was also a fairly wide digital signal on either side--strange.

At 0925z on the KFS Omni the 4108 and 4109 dashers are still going, but the nearby digital signal is gone.

Offline Teotwaki

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Re: 4107.8 slow dasher
« Reply #3 on: March 19, 2022, 0325 UTC »
Guess this is is is a utility signal of some kind.

On the KFS Omni at 0430z there were two long dashers at 4108 and 4109 going at the same time.  When dashing there was also a fairly wide digital signal on either side--strange.

At 0925z on the KFS Omni the 4108 and 4109 dashers are still going, but the nearby digital signal is gone.

I also saw the synchronous dasher and the digital stuff last night and decided it was something un-piratey, lol
Jim
NRD-525, Elecraft KX3 and Elecraft PX3 Spectrum Display
76' end fed long wire & 66' off-center fed dipole for 10/20/40 meters
Orange County, SoCal, The better half

Offline zeak

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Re: 4107.8 slow dasher
« Reply #4 on: March 21, 2022, 0213 UTC »
The signal surrounding the two what appears to be CW signals a 4109.00 and 4107.80 are synchronizing signals for an independent sideband biphase data waveform offset above and below the 4109.00 and 4107.80 synch signals. During the period of the long dash on those two frequencies, bi-phase digital data is sent on the synch signal’s upper and lower sidebands, given that, the whole thing is a fairly complex waveform. The data sent on either sideband is very different coding, although both data streams are bi-phase; there’s no signal/data related correlation in either time (bit rate) or frequency domain of the two.

The bottom line, Teotwaki has it right, these are no beacons and very “un-piratey”, the modulation waveform are some sort of commercial or Mil point-to-point data signaling.

My apologizes for all the verbiage, but became fascinated with the signaling process, never saw it before and my curiosity got the best of me over the last week and spent a ridiculous amount of time in the analysis of the signal waveform.
Zeak,

Receiver KiwiSDR
Ant(s): 80m dipole at 15m and 1m Loop
Location:  DM12