Questions tagged [signal-identification]

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2answers
26 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?
2
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2answers
759 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?
1
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1answer
59 views

Combining/splitting three different RF signals

Not being so fluent in RF, I decided to ask here if my current approach seems doable or how one would try to achieve something like this: I'm doing research and deciding on an approach for my proto-...
2
votes
1answer
112 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 ...
5
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2answers
533 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. ...
3
votes
1answer
208 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 ...
1
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1answer
221 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, ...
4
votes
2answers
200 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 ...
1
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0answers
37 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 ...
2
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1answer
109 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. ...
0
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2answers
129 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 ...
3
votes
1answer
346 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 (...
4
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2answers
208 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?
2
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1answer
676 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 ...
1
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1answer
118 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.
2
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4answers
249 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 ...
3
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1answer
254 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 ...
3
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2answers
244 views

What is “Meter” referencing in “60-Meter Band”?

I know that there are various bands referenced in meters (or cm). My question refers to what exactly the word "meter" is referring to when identifying the 5MHz band? I know that the 60-meter band is ...
5
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1answer
210 views

What kind of modulation is this?

I was able to demodulate a signal I've recieved in gnuradio. Here you can see my flowgraph: But now I would like to be able to send data as well. But how should I modulate my data? As you can see I'...
1
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1answer
175 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 ...
2
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3answers
119 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 ...
5
votes
2answers
223 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 ...
6
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2answers
171 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. ...
1
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1answer
44 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?
2
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1answer
113 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 ...
2
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2answers
202 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 ...
4
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1answer
402 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 ...