Many thanks to SWLing Post contributor, Carlos Latuff, who writes from Brazil:
[Please check out this] audio sample of a signal I heard today (July 20, 2021) around 07h17 UTC on (at least) 4 different frequencies, simultaneously:
– 16166 kHz
– 16716 kHz
– 16747 kHz
– 16839 kHz
Always the same. Five beeps repeating in intervals of 30 seconds.
Another mystery to be solved by your readers.
Thank you for sharing this, Carlos. Hopefully, a reader can comment and ID these beeps for us!
Thank you all for these insights.
Not hearing any beeps but I hear what sounds like weak teletype transmissions on all of these frequencies. 0100 UTC, on July 27, here in South Carolina, USA.
I think Neil’s comment about linked data transmission is the most logical one.
Seems not to be worldwide spread, as per http://websdr.ewi.utwente.nl:8901/fullday/
At least not captured here in EU, even if Brazil is quite distant form Nederland.
So I agree on possibly being “somewhere ‘near’ you, maybe a large facility with the wireless device that is testing itself in intervals of time to another device or two an operator”.
My 2 cents. Cheers, e.-
Its either coming from commonist China or Russia.
I am guessing that this was in SSB.. It could just be a tuning cycle of an automatic antenna tuner on some linked (remote) data transmitters. – just lucky timing 🙂
I was Just checking those frequencies right now on several Web SDR receivers.
Most seem to be sending some type of high speed data.
Makes me wonder if the five beeps you were hearing was some sort of “wake-up tone” being sent to alert receivers that data transmission was coming. It would have been interesting to see if you had listened longer if the beeps were ever switched to data.
73
Bill WD9EQD
Smithville, NJ
That’s a good guess about the intialization tones. I have heard that on ALE/Selcall radio systems before used for HF datalinks.
It seems to be an wireless device that is testing itself in intervals of time to another device or two an operator. Somewhere “near” you maybe a large facility with the device. Sometimes is hard to determine what type of device and from where the signal comes from.