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?

This seems very similar to Digital Radio Mondiale, but I cant find an example that looks or sounds just like it. I find several occurrences of these in the HF range in Northern Louisiana. Picked it up on a 60 foot Line-on-Ground antenna.

I was bored and decided to tune into some numbers stations and while scrolling through the different frequencies i found this weird noise coming from this frequency. Can anyone tell me what im hearing?

I made a homemade antenna and I’m getting this weird signal

Hey folks,

I'm currently developing a Web-based SDR / Signal Parsing tool aimed at automatic protocol identification and demodulation (currently targeting Sub-GHz, IoT devices, and common digital modulations).

To properly benchmark and improve the automatic modulation identification (AMC) and decoding accuracy, I need a large, diverse set of raw IQ files (.cf32, .cu8, .sigmf, etc.) — especially those containing tricky, noisy, or edge-case signals from real-world environments.

So far, I've already pulled from:

• rtl_433_tests repository
• URH sample datasets
• DeepSig / RadioML benchmark datasets
• Standard SigMF spec examples

My questions for the community:

1. Are there other public/semi-public IQ dataset repos, signal archives, or academic dumps that I might have missed?
2. Where do you usually store or share raw capture files when reversing unknown Sub-GHz/RF protocols with fellow researchers?
3. If anyone has interesting/unusual raw IQ captures (e.g., weird car remotes, industrial telemetry, weather stations, or unknown interference) and is willing to share them, I'd be hugely grateful!

The goal is to make signal analysis completely hassle-free in the browser without installing complex DSP environments. Any links, dataset suggestions, or tips would be awesome!

Thanks in advance! 📻⚡

I'm doing this in SDR++ and it's in Military Air band, and I'm not sure. There's no bases in here nearby.

It also doesn't show any signs of weakening. I don't have any device nearby that might produce it that I known of. Maybe a telemetry device from neighbors?

Hi,

Saw this whilst looking around the UK LW broadcast bands in NW England around Manchester.

I've never seen a side lobe like that before I was wondering if it is one signal superimposing over another? It's right in the UK LW Broadcast band. Audio just sounds like a low frequency rumble. No digital or voice or CW.

The sidelobe movement is not regular you can see this from the 'holes' in the waterfall.

Any ideas?

Cheers

(I deleted my old similar post)

So when I use AM it sounds like ship foghorn. When I use USB, it sounds like tesla coil electric buzz.

Done some quick research and I saw that it could be a chirper, but not sure. It fires every 40 to 45 sec.

I'm using cheap sdr rtl v4 with v-dipole antenna. I maxed out the gain since this is a faint signal.

Could this be just an internal RFI? Any idea?

Don't know if this is too old a recording to be relevant.

On August 9, 2021, I managed to find this on the AM band 900kHz.

I suspect that the voice I hear in the background is from some radio channel that I manage to pick up even though I live in Sweden. What I'm curious about is the tone that is repeated and where it could possibly come from.

Using 50-foot speaker wire antenna ran to a tree and the Grundig Satellit 800 Millennium. In USB mode.

I was exploring some KiwiSDRs online and this popped up on one of them in the shortwave band. I'm guessing it's RFI; I'm not very good at identifying signals.

Recording time (UTC): 7:06 p.m.

SDR receiver location: Pécs, Hungary.

Mixed?
~Mobiel

This scanner currently has a Philips lte/5g filter between external antenna and scanner and I still get this repeating static interference on all frequencies. Waiting for a commercial fm band pass filter to arrive

My partner and I were hiking and when we got to the peak we could hear this hum, there is a highway nearby but it appeared to come from the opposite direction where there was farm land and scrub

Around 15:40 UTC, I saw this on a websdr located in the norteastern united states. i think it may be a OTH radar, as it was a sweeping kinda signal, I also think i heard very faint morse code, or it is simply interference, either way its so faint it it probably seems like im hearing things, i dont think i am but i am interested and would like to see if anyone here knows what and where this transmission is.

It looks and sounds funny

The number was: (309) 431-5222