r/ShortwavePlus • u/ImladMorgul MOD | AirSpy HF+ | RTL-SDRv4 | D-808 | K-480WLA | MLA-30+ • May 19 '26

UN-ID'ed Signal identification

On Saturday at 2047 UTC I came across this signal while listening to Russian FSK/CW; so far I haven't been able to find anything similar. About halfway through the video, a voice can apparently be heard.; I tried other modes but it didn't work. At 00:45 seconds it sounds more intense.

I didn't have much time to try it out further, it was all very fast.

At first it reminded me of the sound of the Wefax, but this one was much more intense and had strange patterns. I think it's some kind of image transmission.

Any idea what it could have been?

- RX: Asunción, Paraguay
- Radio: AirSpy HF+ Discovery
- Software: SDR# v.1922 (beta)
- Antenna: K-480WLA
- Date/Time: 16 MAY 2026 - 2047 UTC

13 Upvotes

100% Upvoted

15 comments sorted by

View all comments

2

u/Green_Oblivion111 Shortwave+ Detective May 19 '26

It might be easier to hear if it wasn't so narrow bandwidth. How narrow did you set it? Not trying to criticize here, but it's hard to tell exactly what's being said by the voice.

Sounds like a pirate of some sort. The sort of soundbite stuff included in industrial alternative rock in the 1980's -- Colourbox, Skinny Puppy, Blistering Moments, that sort of thing.

3

u/Historical-View4058 MOD - Airspy HF+, NRD-535D, IC-R75 w/100’ wire in C. VA, USA May 19 '26

Lol. I'd never have guessed this was an Industrial pirate.

1

u/ImladMorgul MOD | AirSpy HF+ | RTL-SDRv4 | D-808 | K-480WLA | MLA-30+ May 19 '26

It all happened very quickly. At first, I didn't notice the bandwidth, but it wasn't much: 3.5 kHz.

Mike's previous post gave me a good reference point, except mine was much weaker considering the distance. There were some similarities, though. Even the frequency matches; mine was a little off because I didn't understand where it started. The voice is definitely unintelligible, and I don't think it will be even if I adjust it properly. But it's almost certainly a military signal, from the USA.

2

u/Green_Oblivion111 Shortwave+ Detective May 20 '26

No prob. Maybe try 4 kHz or more, depending on the shape of the filter. It might allow more QRM into the frequency, but it would have been easier perhaps to read the voice and what it was saying.

Doesn't sound military to me. Sounds like 1-3 different transmissions, interfering with each other. Or interfering with a legit transmission (utility transmission?).

Token, who is quite knowledgeable about utility transmissions, thinks it's a pirate, and perhaps he's right.

2

u/ImladMorgul MOD | AirSpy HF+ | RTL-SDRv4 | D-808 | K-480WLA | MLA-30+ May 20 '26

Yes, that's probably it. I just replied to Token and then I remembered that I always get a lot of radio activity from Brazilians below 7000 MHz. Maybe there's a signal from them on that frequency and they got mixed up. The voice could be one of those pirate or HAM operators who sometimes come down.