What are these signals (3-5 GHz range, about 300 Hz wide) on SDR waterfall

skywatch1234

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Jun 25, 2020
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Hello,

I was playing with a HackRF 1 and CubeSDR on Linux to view the RF spectrum. The HackRF goes to max 5Ghz and I noticed some streams in the range of 3 GHz - 5 GHz.

There are several dozens of these very thin lines in the waterfall at misc frequencies in the 3,4,5 GHz range. They are around 250-300 Hz wide and when made audible only resulting in a perfect sine. All these ultra thin lines in the mentioned range have the same characteristic. Some higher some lower though the amplitude (signal strength) varies. These signals always broadcasting and varying between a perfect sine (mono tone) to (on some days) an oscillating sine (looks like a "standing wave" visually, sounds like a sine tone in pitch modulation).
No other signals carried or modulated over these signals.

I know this range is used for sat comms and I sometimes see some sat data in the range, with the usual sound (when made audible) of digital communications) so I know these are not the typical sat coms. They are not only in my vicinity so they must be commonly known signals.

Can anyone please give me a hint on what I'm looking at?

skywatch
 

dlwtrunked

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Dec 19, 2002
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A couple questions:
1. What antenna are you using? Is is directional and if so, where is it pointed?
2. Can you tell us more exactly some of the frequencies?
I suspect what you are seeing are not real communication signals but some sort of interference but need to know more.
 

KR0SIV

Sarah Rose She/Her
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The HackRF is pretty well known for throwing images of nearby strong signals. Very likely the signal is not where you think it is.
 

skywatch1234

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Jun 25, 2020
Messages
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Hi, Thanks for your replies.

I know well how various transmitters sound. It's not WiFi or regular digital communications. It can't be because they are between 3000 Mhz and 5000 Mhz and a few dozen of small bandwidth lines (distributed unevenly over this 2ghz span, and perhaps well beyond). They are only 200-300 Hertz in width and show up as very narrow lines on CubicSDR. If I tune into them and select USB audio and minimize the bandwidth (to cut the noise to < 500hz) all I hear is a perfect tone (with a sine form on display).

So we are talking about perfect sines, 200-300 hz narrow in the 3-5 ghz region. Are these sats? Are they resonance frequencies or something? This by the way is part of a research into "Organised Gangstalking/ Targeted Individuals/ Sleep deprivation (looking for skull/bone resonance freqs) " It could be totally unrelated and some of the signals are visible outside the target house, in a field away from cities.

The sines are the visual representation and the only thing changing is the amplitude. It has the look of standing waves with a perfect sine but only the amplitude shifting sometimes, but not always as if there is schedule. The audio of when the sine isn't perfect but "modulating" sounds like 2 simple tones blended. Nothing fancy, no other results with other demodulation types (AM,FX,IO) as its just a simple sine (or rather, about 30 of them on a 2ghz span being distributed, all about average 250hz with only background noise left and right ) . No digital transmissions because the bandwidth is just too narrow. It must be some kind of signalling system or something keeping special freqs occupied (for what reason?) Maybe it could be pings from satellites ? Anyone know ?

Possibly WiFi AP's/Routers?
No I know how those sound and show up on display.

It's also not regular sattelite traffic although its in the freq band of sats.

It's also not interference or a harmonic. I researched that before.

The HackRF is pretty well known for throwing images of nearby strong signals. Very likely the signal is not where you think it is.
I calibrated the HackRF1 and other freqs such as UMTS align up almost to the Hz

But these sines (with sometimes a little amplitude modulation) are strange signals. 250 Hz bandwidth and so many of them between 2 ghz up to 5 ghz (maybe well beyond because this is where my hackrf with omni directional antenna stops) . I repeated the experiment 30kms away and it shows most of the same frequencies. I believe these are in orbit somehow as the range (3ghz+) in Europe is used for monitoring sats

I'm interested in hearing from people who monitor sats on what this could be

A couple questions:
1. What antenna are you using? Is is directional and if so, where is it pointed?
2. Can you tell us more exactly some of the frequencies?
I suspect what you are seeing are not real communication signals but some sort of interference but need to know more.
Hackrf1 with omni antenna and CubicSDR

The freqs are 250 hz , visibly and audio just a sine although on some days it sounds like 2 sines mixed (to the ear) but on visual display it looks like a sine not out of phase, like a standing wave, only with tops (amplitude) moving up and down but no moving sine (although this could be due to cubicsdr)

Nothing left or right of the sine wave for several Mhz or even up to 100 Mhz.

There are about 30 of them between the 2 ghz and 5 ghz range.

It's different from digital comms and sat comms. And its clearly a signal, a very pure and clean signal but not enough bandwidth to be an actual transmitter of known comms like audio, video or data.

To avoid interference I tested with another laptop outside in nature 30kms away from cities.
 

dlwtrunked

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I can't explain the 2 gig, but the 3 to 5 gig could very well be satellite beacons.
He is not going to see such things with his antenna setup. And the low end of 2 GHz is more likely for sat beacons than 3 or 5 GHz.
 
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