It’s on 458.8mhz, NFM, 5khz bandwidth, it appears to originate from a local water tower to me, but I am truly stumped as to what modulation this is, and what modem would produce it? It transmits constantly day and night, and the data appears to vary so I don’t believe it’s a placeholder signal, any ideas would be really appreciated it’s been driving me crazy trying to figure it out

Captured: Aug 31, 2026 17:22 UTC.
Baseband wav file (UINT16): https://drive.google.com/file/d/17FQYJ9zM4ORt7d0kVLSW_pQcK4S1xEAz/view?usp=sharing

So by the looks from signal identification wiki, I assume it's a scrambled voice. But I can definitely hear some numbers and discernable word so I doubt.

Additional context:

- it's nearby active XSQ Guangzhou Station broadcast frequencies (I always see those 3 long dash then XSQ in morse code plus WEFAX).

- I also found a DSC from Ho Chi Minh Ville Radio nearby.

Is it maritime broadcast radio that gives some sort of direction?
Or maybe just a traditional shortwave station?

Signal looping for a good hour on 4779 LSB, received on my D808; you can hear it right now on UTwente.

Newbie.

So I heard this signal when I visited a nearby sea port. Did some digging and I found that it's kinda similar to this: https://www.sigidwiki.com/wiki/2G_(GSM)_Global_System_for_Mobile_Communications_Global_System_for_Mobile_Communications)

Is it GSM 2G? Or Am I just hearing things (sorry my hearing wasn't that good)?

EDIT: Sounds similar to when you put your old phone nearby an old speaker and you're about to receive a call.

I've been using Artemis for awhile and love it, but are there any other standalone tools for SIGID? Is there anything AI-powered for auto identification? I know about OmniSIG but curious if the community has made any open-source options.

I've come again to ask for help. Initially I saw this signal on 14MHz and after a few minutes it stopped and resumed on 18MHz. At first I thought it was an OTH radar initially but towards the end the tone of the emissions changed and leads me more into the realm of HF data. Still am unsure though, Im trying to learn I swear.

Quelqu’un pourrais m’expliquer ce que cela peut être ?? C’était sur une fréquence bien particulière.

Often can be found on 9A6NDZ webSDR at 145,65. On the same frequency a repeater under the callsign 9A0VOR beacons occasionally. So could just be someone with a faulty PTT constantly opening and closing the repeater, but what do you think? The recording used FM.

I think this might be ALE...maybe? I suck at signal identification im trying to get better lol.

• Description: This video explains how the Karhunen‑Loève Transform (KLT) outperforms FFT in low‑signal‑to‑noise environments. It presents a case of detecting faint interference signals in GNSS satellite navigation systems, discusses the high computational complexity of KLT, and introduces the BAM‑KLT approach to alleviate that issue. Based on experimental simulation results, the video evaluates the potential of KLT to become a key tool in future signal processing.

What are those?

• Description: It explains that phase‑synchronized RF signals play a key role in improving spectral efficiency and SNR in modern wireless communications. Through examples and simulation results, it shows how critical precise phase control and timing synchronization are when implementing spatial‑diversity technologies such as multiple antennas, MIMO, and beamforming.

The frequency is 6.385 khz in AM, what could this crackling noise be?

It went like doooooOOOP doooooOOOOOP DEEEE DEEEEEEEEEEE wooooooop and repeated a bunch

Context, I assume this not an RFI or harmonics since it doesn't produce an almost unchanging sound. I also tried decoding it with RTL 433 to no avail. Any info?