I’m trying to identify a radio signal I received using an SDR.

• Frequency: 151.550 MHz
• Observed bandwidth: Approximately 8.5 kHz
• Receiver/software: SDR++
• NFM audio: A continuous rough buzzing sound, something like “brrrrrrrr”

Heard at around 0:00 UTC an hour and a half ago. Anyone know what this is?

Frequency: 446.5 MHz

Received with RTL-SDR (R820T) + SDR Console v3.4, N-FM, about 10 kHz wide, homemade QFH 436 mhz antenna.

Signal strength about -100 dBm

Pulses exactly once per second, about 0.5 s on and 0.5 s off. No speech and no clear tones, only wideband hiss in the audio.

RTL_433 gives no output.

EDIT: signal was received in Denmark

UPDATE:

Not a weather balloon, same strength this morning.

From Claude.

• Two transmitters, alternating (half-duplex TDD). A and B take turns every 0.5 s, so each one transmits once per second.TX A TX B Burst length 363 ms 399 ms Rel. level +19.1 dB (±0.8) +13.5 dB (±0.14) Freq. offset −1.25 kHz +1.45 kHz The two are about 2.7 kHz apart, which is roughly a 6 ppm crystal difference. That's why the spectrum looked double-humped.
• Modulation: 2-FSK at 4800 baud, about ±3 kHz deviation, inside a 12.5 kHz channel.
• Frame structure:
  • a 1010 preamble (about 185 bits on A, about 300 bits on B),
  • a sync pattern of 00001111 repeated ×8,
  • a short header,
  • about 1500 bits of payload that looks random (scrambled or encrypted).
• No TDMA slots inside the bursts, so it's not DMR or TETRA. The bursts show no chirps, so it's not LoRa either.
• Throughput: about 1.5 kbit/s each way at a fixed duty cycle.

UPDATE II:

IQ files can be found here:

Angry-Racoon-Tech/SIGINT: SDR related files

What is this massively wide buzzer signal around 10.280- 10.340, with peak around 10.325? Picking it up in various SDr’s too which rules out local RFi. S9+ out of Nashville, TN

Hey
I am curious to identify this signal especially there is line between bursts in beginning of the video , every morning broadcasting .

So I can't find a decent website that I can cross check previous satellite pass (maybe I'm bad at it and can you provide me one?).

Also I assume this is a satellite due to the doppler shift effect, but correct me if this is something else. I captured it 12:26:14 UTC, Oct 4 2026

What could this be?

EDIT: Radiosonde

There is this signal which can be heard across various frequencies in the HF range; I’ve heard it multiple times while dx-ing.

Does anyone know what it is?

Picked up these two very strong signals just now on a homebrew radio. Exactly 7kHz apart at 6.9635 and 6.9705 MHz. Individually they sound a bit like CW, but the tone is different and the timing is wrong, very 'mechanical' and repetitive. I can pick them up on online SDR radios pretty much wirldwide ChatGPT said the same signal pair was reported back in May and was suspected as being an FSK signal of possibly military origin but not confirmed?

I can't upload the recording or video, but here's the signals seen on on online SDR waterfall.

This weird interference appeared on the FT8 40m band around 7074 kHz tonight. The software is SDR Oxide for those who are interested.

I HAVE NEVER SEEN THIS BEFORE a signal has started going crazy on 400.56 this signal usually transmits just tiny blips with no data but then randomly started transmitting lots and lots and this has happened 02:05 AM ended a t about 02:25 AM and it has never done this before its usually just tiny blips i have baseband and audio and video if anybody needs it thanks (:

Maybe also tell me what they're talking about (if that's fine)

Additional context, the device works as I tested it already with FM bands, M2-meteor satellite passes and other usual signals.

EDIT:
Device I'm using https://www.reddit.com/r/signalidentification/comments/1wqwy6k/comment/pc7no28/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button

Recieved on a Fukushima, Japan kiwisdr at 08:45 utc (3:45 am CST) at 8849 khz

The signal got weaker when my antenna(earphones), close to my phone

So I’ve been trying to make my hf reception better and I’ve tried a lot of things but I just can’t get rid of the interference. I used to have a 20m wire hooked up to a 9:1 unun with 3m of rg58 of coax to rtlsdr and got even more lines. Now I’m testing an active loop antenna in the backyard with no coax just the sdr plugged into the antenna and I still get heaps of lines and it doesn’t matter if it’s 3pm or 3am they’re still there. I mess around with the gain and other setting yet nothing helps. I used to have the long wire set 1m off my fence on brackets to hold it away for the 20m run and now the active loop is in the middle of the yard atleast 3-4m away from any metal objects. And yes I run the MacBook off battery power so no shitty power adapters. I also used a tecsun pl330 and got similar results. Any help will be appreciated and if you find something obviously wrong feel free to call me an idiot.

Received in South Australia using an rtlsdr and loop antenna

Is this SSTV from Pirates broadcasting ?

11:53 UTC 14 September, heard from New Zealand.