rtl-sdr help coach wanted

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Joined: Wed Oct 14, 2020 8:36 am

rtl-sdr help coach wanted

Post by modbee » Wed Oct 14, 2020 10:33 am

Hi there,

I am totally new to SDR, but somewhat experienced with PC's and different OS / Networking.
It all started with buying a cheap "Wish" clone - SDR, which resides in my trash bin ever since.
I went on to buy a RTL-SDR.COM V.3 from Amazon, and .... voila
It is recognized at least as an existing device (trying all of this on WIN - XP, 7, 10, Raspberry + Linux-Lite)
I went on to

- install SDR-Sharp (Zadig - in appropriate version),
- Cubic-SDR
- GNU-Radio Companion
- tried different antennas
- moved the SDR to a powered usb-hub

but to no avail, I am getting nothing else but a white background noise and a waterfall indicating that some peaks exist.

I would be aiming at grabbing some FM/AM Stations first and move on to listening to some HAM later.

If I put an 5,- $ radio receiver in vicinity of my SDR antenna-loop, he will catch at least some FM/AM local stations.

So I am guessing that I am doing something essential totally wrong (for several weeks).

This is what my GQRX Window looks like, and all I can hear is static "crackling" noise .....
Capture_01.PNG (416.65 KiB) Viewed 807 times
Anybody willing to coach me ??

Today I noticed that the usb-stick / dongle is getting rather warm (50 to 60 °C), so I am guessing that it might be a faulty stick ?? (Since I never managed to grab a single broadcast) ??

Just curious how to verify this before sending it back ...


best regards & thanks in advance

G. Breite

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Re: rtl-sdr help coach wanted

Post by weathersatelite » Thu Oct 15, 2020 5:17 pm

i can see from your screen shot that you are not tuned into any nearby freqencyes. try tuning to a radio brudcast station thta you wold listen to in you car. take not that you are in kilherts not mega herts to freq change number.

examble you want to liten to 100.1 you tuen to 100100 kiliherz

also the dongles to get warm that is to be expected. i do not know just how warm though.

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Re: rtl-sdr help coach wanted

Post by rtlsdrblog » Fri Oct 16, 2020 5:35 am

What antenna are you using? And what in particular are you trying to receive? In the screenshot you're tuned to 1 GHz, you're not likely to find any signals there.

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Re: rtl-sdr help coach wanted

Post by modbee » Fri Oct 16, 2020 7:56 am

Hi there Weathersatellite,

thanks for your advise. I went through the entire frequency range and found:
Capture_02a_.PNG (99.36 KiB) Viewed 731 times
minimum, which is 24000.000 kHz
Capture_02b_.PNG (137.85 KiB) Viewed 731 times
maximum, which is 1766000.000 kHz

I was expecting some radio stations in the range of: 88 to 108 MHz (88000 to 108000 kHz) on WFM

As antenna I was using a small loop antenna rated 100k to 30 MHz

uups, I think I just answered it myself. Must be an antenna (not suitable) issue

Now I tried a home-stereo wire antenna (working fine on the stereo) ....
.... situation remains the same. Not grabbing any station in the entire range, only white noise (peaks showing).

I am now sending back the dongle and wait for replacement to arrive.

best regards so far

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Re: rtl-sdr help coach wanted

Post by rtlsdrblog » Fri Oct 16, 2020 8:23 am

And did you adjust the gain?

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Re: rtl-sdr help coach wanted

Post by waterman46 » Mon Oct 19, 2020 4:22 pm

I think your problem is not setting frequency correctly. Pay attention to the big frequency numbers in upper left of spectrum display. They are in Hz. In your first screenshot you are tuning to 1 GHz ( Hz) and there are some signals showing peaks. In that band, near cellphone frequencies, I believe you only will have digital coded data. In your second and last shots you show 24MHz and 1.7GHz. There isn't going to be much activity on 24MHz and 1.7GHz will also have digital data signals, I believe.
Tune to 88-108MHz. Center at 100.000.000 Hz in the spectrum display window. Set sweep bandwidth to about 5 or 10Mhz. Set modulation to Wide Band FM. Use a wire about 8' long strung up in the room. You should receive strong local FM stations. Also tune AM band between 500.000 Hz and 1.700.000 Hz with modulation set to AM.
My RTL-SDR V3 receives those, but FM audio is distorted. Got it few days ago. I get AM band OK. Have not experimented much beyond that.

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