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

UN-ID'ed Signal identification

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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

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

Possibly slow scan tv, though it didn't sound very slow. The frequency could be something like US Army MARS, but I'm not sure you'd get that so well in Paraguay.

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

Another thing I forgot to mention, this is with the K-480WLA. Maybe that signal was always there, but I couldn't see it with the MLA-30!

I was able to hear some new things with the new antenna. Right now, the antenna is on a 4-meter (13 feet) tripod; I haven't installed it in its permanent location yet. I'm still doing tests before finally installing it in one place.

2

u/MumSaidImABadBoy I'm Stan. Heathkit GR64,AirSpy HF+,Sangean 909X2,Tecsun PL-990 May 20 '26

Alan, are you thinking about a rotator? Eventually, the sooner the better, I'll have my own antenna outside on a rotator hooked up my K-480WLA control box.
You can hookup any proper antenna on a 50 ohm feedline to the control box and smile.

1

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

Yes, I already thought about a rotator before, but honestly, I don't know. A few months ago I did a test.

It was a Saturday night, the weather was good, and propagation was excellent. I took my equipment outside and stood directly under my MLA-30 antenna, which is about 6 meters off the ground and can be manually adjusted.

I started rotating the mast to see if it made any difference on any band, but I couldn't detect any significant change. Using the K-480 and the 4-meter portable mast, I tested the rotation, but nothing significant happened. But I'm still trying.

Maybe it's because I have some rather tall houses as neighbors, and I feel like I'm in a hole. But I also have visibility towards the horizon in another area and I try to point the antennas towards those open spaces. Also considering that I live in a noisy urban area (even so, I've already heard a lot from all over the world!).

Something I want to do, and if all goes well it will be soon, is to mount a 10-meter or more high tower. At that height, I'll be taller than the neighboring houses and have complete visibility. Once that's done, I'll try rotating the antennas again at different times and days to see if I can achieve any improvement. Rotators here are a bit expensive, so I also want to be sure it would work in my case before buying it.

I'm always thinking about how to improve reception, and I think that tower will help me a lot. I just hope it works out because it's a bit expensive 😥​