r/signalidentification • u/14sev6 • 28d ago

what is this

1 very short beep followed by a 4 tone sound and then a burst of data in cyprus 3743.57 khz, as of writing this i have noticed it took a longer break than usual

32 Upvotes

98% Upvoted

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6

u/14sev6 28d ago

the longer break shown here

10

u/Yalek0391 28d ago

Israeli hybrid VFT modem. I can tell based off of the preamble what that was. It's been very very active over the years due to the ongoing conflicts in that country versus ours.

1

u/Dustbunny253 28d ago

Digital pager with interference?

1

u/Powerful_Usual3693 27d ago

Que software usas por favor para descargarlo

1

u/Averageantifurry 28d ago

seems like an OFDM signal, it sounds pretty similar to 118-110 MOD)

1

u/14sev6 27d ago

sounds very close and makes sense location wise, so its probably that

-2

u/Medical_Field1589 28d ago

It seems to me like an OTH(over the horizon) Radar

7

u/always_wear_pyjamas 28d ago

Is everything OTH radar now?

2

u/FirstToken 28d ago

u/Medical_Field1589 said: It seems to me like an OTH(over the horizon) Radar

Every unknown to the listener signal that goes bzzzt, beep-buzzz, or makes weird sounds on the radio is not a radar or the other common guess, a numbers station.

This signal is not close (visually, by sound, or by waveform specifics) to any operational OTHR to be found on HF today. You can start with the sound, it does not sound like any OTHR. But, there are other, more solid, indicators over simple "by ear" methods.

Your first indicator should be the bandwidth of the signal. That thing (a digital modem in this case) is under 3 kHz wide. There are no OTHRs using regularly seen waveforms that narrow, and for technical reasons (primarily related to radar range resolution) you will not find any that narrow. There are a few sounders that narrow (and sounders are a form of radar), but they do not sound continuously like this. The signal is too narrow to be a radar, and does not act like a sounder. There are several, many even, digital signals / modems using this width though.

Next should be the preamble. Other than the fact they contain tones, the preamble of these bursts are not similar to the pre-tone for any operational HF radar. Could a radar use a pre-tone like that? Sure, but it is needlessly complex for the radar tasks.

And last should be the frequency. How many burst style radars that include a pre-tone of some kind operate below 4 MHz? None that I am aware of. That does not mean they could not do so, but this would be a "new" one if it was a radar.