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Questions tagged [signal-identification]

Questions about identifying signals of unknown mode or origin.

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Phase-Based Ranging

I've been reading a lot about Phase-Based Ranging (PBR), and it's all starting to become very intuitive. BUT; There is one technical, but extremely important, detail that seems to escape me. When the ...
Hysan Happy's user avatar
1 vote
2 answers
133 views

What is this pulsating signal?

When scanning through UHF, I find that there are a few frequencies that made a sound similar to a fast drum (~300 bpm?) Here are a list of the frequencies: 451.200 MHz 454.280 MHz more coming soon ...
o'o's user avatar
  • 513
2 votes
1 answer
281 views

What is this weird interference/strange radio station?

When I was checking if my antenna is working properly using websdr.org, I came upon this: On 4480 kHz, there are some strange noises. You can also see it in the waterfall here. Is it just some ...
o'o's user avatar
  • 513
-3 votes
1 answer
238 views

Unstable frequency generator using gnuradio 3.10

I run gnuradio on Windows 11 using anaconda install. It uses hackrf without portapack. I am using a signal amp from an F16 fighter jet. It requires 10 dBm input and runs on 24 V 2 A. Picture here It ...
markl17's user avatar
3 votes
1 answer
488 views

Help on identifying signal type and extract audio from a signal

I Just recorded a signal using SDR++ and RTL-SDR. I can recognize even without any demodulation so I think it should be an AM modulation but AM demodulation doesn't give me a clear audio. I also tried ...
Ariyan's user avatar
  • 143
0 votes
1 answer
173 views

Identifying the signal picked up at 363mhz with sdr++. It is from Burmese military's communication. I want to know what it is and how to decode it

As shown in the picture, I want to identify the signal and how can I decode it, please. Here is the link to audio.wav file: https://u.pcloud.link/publink/show?code=XZRoY5VZggSdx8NPqKp3hAOaphcsKVVCqrik
Maung Maung Gyi's user avatar
-2 votes
1 answer
89 views

How to know whether aliasing occurs when observe unknown signal?

Per my good but downvote question,I am hard to set sample rate even to a standard cosine wave. When I observe unkwon signal,how to judge whether aliasing occurs?
kittygirl's user avatar
  • 650
3 votes
1 answer
134 views

Zigzag line on CB band

I'm seeing this strange signal on the CB band around 27 MHz, at a glance it looks similar to NFM modulation, but it's just noise when tuned to. It's transmitted about every minute. My setup is RTL-SDR ...
MightyPork's user avatar
0 votes
0 answers
108 views

Can you identify the modulation of this signal?

I picked up a signal on 434 MHz (in Europe). Can you identify the modulation or give me a hint on howto analyze it further? I tried finding a similar signal on https://www.sigidwiki.com without ...
jackson.c's user avatar
5 votes
1 answer
767 views

bizzare CW on 2m

I'm currently in Kershaw, SC. Yesterday an automated signal popped up on a 2m simplex freq (147.455 MHz) and has been running since. It sounds like Morse, but it is random letters that don't seem to ...
Aaron's user avatar
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0 answers
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What modulator is used on this audio file? (it should be ASFK1200, but not recognized)

I have this audio file (WAV) that I'm trying to decode using multimon-ng (also tried Qtmm AFSK1200 Decocoder). It should be using AFKS1200 but multimon-ng can't demodulate it and by the looks from the ...
Chris8580's user avatar
-3 votes
1 answer
460 views

How to record and replay the `center frequency` when `file_sink`?

Workflow as below: When file_source after file_sink,center frequency is not recorded and ...
kittygirl's user avatar
  • 650
1 vote
2 answers
107 views

What's the `Minimum signal duration` and `Minimum detectable signal duraion` of Ettus B210?

When read keysight 9913A manual, Minimum signal duration with 100% probability of intercept (POI) at full amplitude accuracy 12 µs Minimum detectable signal 22 ns What's the ...
kittygirl's user avatar
  • 650
3 votes
1 answer
97 views

Fourier transform of air breakdown impulse waveform

i am a beginner on signal processing. I learned from some papers, site online, including this forum that lightning discharge or any electrical arc emits wideband radio frequency. because the odd ...
Ramanda Nvl's user avatar
3 votes
1 answer
419 views

Open source RS41 decoder

I would like to decode the signal from a RS41 radiosonde (from a weather balloon), which are suggested open-source software to do that? I tried RS but after compiling the code and executing ...
Paa's user avatar
  • 33
2 votes
3 answers
541 views

Receiving multiple signal

Maybe this is a really silly question even from me, a completely amateur... But I like to know about how's the antenna output when its receive multiple signal Is it possible different signals on ...
Ramanda Nvl's user avatar
2 votes
3 answers
156 views

Wireless signal strength explanation needed

Could you kindly explain me or advise following please... I have a TP-link WiFi router. When I measure signal strength just in the vicinity of the router- literally I touch my smartphone (with WiFi ...
mariolucas's user avatar
2 votes
1 answer
261 views

Unknown signal on 446MHz LSB (possible RFI?)

I am attempting to hunt down many sources of RFI in and near the UHF amateur bands at my home, but I stumbled across a very specific one that I have definitely never heard before. This one sounds less ...
hairlesshobo's user avatar
0 votes
1 answer
507 views

How to identify type of modulation from recording done by gqrx or gnu radio?

Is there a tool or some other way that would allow me to find out the type of modulation of a specific signal? What I specifically try to do is to decode signal from this remote control: http://www....
Łukasz Zaroda's user avatar
2 votes
1 answer
509 views

Icom 7300 low frequency broad-spectrum noise

What's causing these horizontal bands of noise? It's the middle of the day here in a low density city neighborhood. They were not present about 20 minutes ago; now they are even stronger and filling ...
x-ray_kilo_india_uniform's user avatar
0 votes
2 answers
156 views

Local Relay with static

On our local Relay there are from time to time transmissions, where only static can be heard. Most transmissions via relay can be heard clearly. What could be the cause of this?
mike's user avatar
  • 211
2 votes
2 answers
2k views

What is this burst transmission sequence across the entire band?

Fairly regularly on the 40m band I hear a quick blip of a tone, and when I look at the waterfall I see these brief transmissions all across the band that look like little dots. What is causing that?
SandPiper's user avatar
  • 777
2 votes
1 answer
271 views

How does one know how a signal has been modulated

I am trying to intercept signals from a drone remote controller and decode them. Before I can do this I need to demodulate the signals. All I have is radio data from the transmitter's operating ...
Pizza Receptacle's user avatar
5 votes
3 answers
1k views

Unidentified signals on FT8 frequencies

When I work in FT8 mode I often see signals like these: I couldn't identify these signals using SigiWiki nor managed I to decode them using WSJT-X. Though these signals seem to use 15 second frames. ...
Aleksander Alekseev - R2AUK's user avatar
3 votes
1 answer
721 views

What is this odd data/screeching/fuzzy signal?

I was listening to a commercial FM radio station on 100.9 MHz, and this intermittent weird sound kept coming through it. Here is a recording of it. The audio starts at about 15 seconds. It sounded ...
Ben Madison KO4UXC's user avatar
1 vote
1 answer
965 views

What's this digital mode on 40 meters?

Location: Michigan, USA Frequency: 7.074 MHz Time: 1300 UTC Vertical axis: 15 seconds per division Most of this is FT8, and some JT65 can be seen as well. But buried in here is something else, ...
Phil Frost - W8II's user avatar
4 votes
2 answers
238 views

What type of signal is this?

I received this signal around 7 MHz. I've checked all over the "Signal Identification Wiki", but cannot find anything similar to this. I'm pretty sure this is some simple FSK, but that is the exact ...
Risahas's user avatar
  • 41
1 vote
0 answers
41 views

Determining if what's on a frequency is signal, or noise [duplicate]

I have the spectrum binned into 5kHz bins. For each bin, I'd like to determine (via software) whether what's in that bin is primarily signal (an FM broadcast station; a ham repeater) or noise (just ...
Ken - Enough about Monica's user avatar
5 votes
3 answers
296 views

Detecting signals using statistics

I have sampled a section of spectrum every few Hz. I have mean, standard deviation, and range data for every frequency sampled (and I can gather more statistics if necessary). I've sampled for ...
Ken - Enough about Monica's user avatar
2 votes
1 answer
129 views

Signal on various frequencies, about 2.5k bandwidth, sounds like a broken motor turning: What is it?

There are a number of frequencies, where a certain type of signal can be heard. The characteristics is, that every occurrence takes about 2.5k bandwidth, and it is transmitted in a continuous way. ...
DaniZH03's user avatar
0 votes
2 answers
146 views

Any ideas as to what I might be picking up on SDR?

Any ideas as to what I might be picking up on SDR? They make for some strange patterns. Picked them up at the following coordinates: (31.514596, 74.345092) using GQRX, tuned to 217.25 MHz. As for the ...
TayE's user avatar
  • 105
3 votes
1 answer
498 views

What is this Morse code-like station?

I’m trying to identify this signal at 928.807 MHz. A sample of the raw I/Q from gqrx is here (9.2 MB, .wav, 48000 Hz) and this is the waterfall: I’ve tried decoding some common digital modes (...
Henry Elliott's user avatar
4 votes
2 answers
471 views

Very odd and wide 30m signal. What is it?

A local ham friend copied this strange, wide signal on 30 meters on his Flex 5000. Anybody know what it might be?
Mike Waters's user avatar
  • 8,071
3 votes
1 answer
2k views

How do I go about identifying an unknown digital signal?

I'm playing around with an SDRPlay. I'm using the CubicSDR app, and I'm tuning around the HF bands. I get to 5.650 MHz and I see this: This looks like a bunch of discrete RTTY signals. How would I ...
bcattle's user avatar
  • 255
1 vote
1 answer
224 views

How to explain a frequency pic at 1.5 kHz?

I have a pic in the VLF band at 1.5 kHz. What would be the origin of this peak? The graph was obtained by running display_qt in Linux from a laptop.
 j1088099.mvrht.com.'s user avatar
2 votes
4 answers
882 views

Measuring a device's 2.4 GHz RF signal in an open field/indoors

How can I measure/what instrument should I use to identify/measure the RF signal strength in a "noisy" environment? For example, I want to measure the RF signal strength of my device at a particular ...
f0rfun's user avatar
  • 121
3 votes
1 answer
683 views

What might this "spreading" interference be?

Any idea what might be causing this signal to appear in the "panadapter" spectrogram of my Omnia SDR around the 40m band? Every twenty seconds, I get a strong "focused" signal that then rapidly ...
natevw - AF7TB's user avatar
2 votes
1 answer
231 views

What type of digital mode is this?

Currently trying to figure out what type of digital mode I'm listening to. I've purchased a Vaisala Radiosonde RS-92AM. It's a meteorological device usually attached to below a weather balloon. I've ...
Josh Ferrara's user avatar
2 votes
3 answers
159 views

Identifying Local Signal

I've been monitoring a signal locally on 159.150mhz (which is allocated for "Civil Defense"). I believe that this frequency is for the local tornado sirens and I would like to be able to decode the ...
sgmc's user avatar
  • 23
5 votes
2 answers
504 views

What are the continuous transmissions at the lower end of the spectrum?

I'm fairly new to amateur radio, and I've been using a web-based SDR tool in addition to my own radios. Using this SDR tool shows a lot of activity lower down on the spectrum, such as this: When I ...
user9993's user avatar
  • 153
6 votes
2 answers
244 views

Identifying signals in the satellite exclusive band

I have just started playing with SDR so I downloaded the relevant amateur band plan for my location, the UK. Tuning around I found things like POCSAG/FLEX pagers as expected and amateur radio (e.g. ...
David's user avatar
  • 286
1 vote
1 answer
58 views

Determining modulation by spectrum

Is it feasible to determine what sort of modulation is used for a given signal by looking at the spectrum / FFT? Does software like this exist?
Ken - Enough about Monica's user avatar
2 votes
1 answer
149 views

Is this beacon the tail end of a 'Numbers Station' broadcast?

I was recently scanning through the short-wave frequencies and stumbled upon a series of repeating tones, which then cut to classical music and then a woman speaking French (unconfirmed). Later I was ...
Eric's user avatar
  • 69
2 votes
2 answers
248 views

What is this signal I've recorded?

I've recorded what I believe packet radio signal. I tried few decoding tools on windows to no avail. Can anyone please have a look at this youtube video and tell me how to decode this signal or what ...
Tomas D's user avatar
  • 23
4 votes
1 answer
465 views

What is this short, wide band signal?

I've observed a signal I'm unfamiliar with, and am wondering what it might be: The period of time it lasted is 5 seconds, and it occurs irregularly. You might be able to see it too via WebSDR. How ...
Adam Davis's user avatar
  • 12.2k