unknown signal

I was tuned to 4.284MHz, and while using USB mode the signal was centered on an audio frequency of 2KHz, so that means in the RF spectrum the signal was centered at 4.286MHz. It appears to be a fairly wide band mode for HF transmissions, due to it being about 3Khz wide. It has a very flat top to...

Hi ya'll, I've got a mystery signal I've been unable to identify as of yet. Unfortunately, I've only got the audio recording to work from now. Picked up in San Diego county area on 447.3225MHz, bandwidth of approx. 6k. Based on the audio, I think it's a 4-tone FSK, but my ears aren't that great...

I received what appears to be an FSK signal just above 124kHz. I have this small air-core magnetic coil antenna (not one tuned for LF or VLF reception, but it's useful for picking up near-field VLF and LF magnetic signals like holding it near a switching supply and picking up its electronic...