Recieving signal from any flyby satellite

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Paixillation
Posts: 4
Joined: Fri Mar 10, 2017 7:15 pm
Location: Ankara, Turkey

Recieving signal from any flyby satellite

Post by Paixillation » Fri Mar 10, 2017 7:27 pm

Hello everyone so, I am a senior Space Engineering student and I have a graduation project to complete. I have joined the community believing that I might get some tips regarding this issue. So we want to recieve signals from satellites, then we plan to decode it and by using doppler effect we want to determine orbital parameters and such. The thing is, we are not really familiar to radar-antenna subjects.

Possibly LEO satellites will be better for us to track since their period and altitude is lower than GEO sats. What kind of an antenna-dongle we should use in order to get stable signal? Is pointing the antenna to the satellite is a necessity or, would we be good without it aswell? I would really appreciate any ideas, suggestions.

Thank you all, in advance!

rtlsdrblog
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Re: Recieving signal from any flyby satellite

Post by rtlsdrblog » Sat Mar 11, 2017 2:45 am

If it's just the doppler effect that you want to look at you could simply receive signal from the NOAA satellites. The doppler drift is quite noticeable with these LEO satellites from the signal.

Here's a tutorial on decoding http://www.rtl-sdr.com/rtl-sdr-tutorial ... te-images/. But you could just ignore the decoding, and measure the center frequency of the signal. Then deduce the orbital parameters from that.

For NOAA you won't need antenna pointing. Just get a good QFH, turnstile or V-dipole antenna set up on a roof, and have an RTL-SDR dongle with a TCXO, and you're good to go.

Paixillation
Posts: 4
Joined: Fri Mar 10, 2017 7:15 pm
Location: Ankara, Turkey

Re: Recieving signal from any flyby satellite

Post by Paixillation » Sat Mar 11, 2017 8:51 am

rtlsdrblog wrote:If it's just the doppler effect that you want to look at you could simply receive signal from the NOAA satellites. The doppler drift is quite noticeable with these LEO satellites from the signal.

Here's a tutorial on decoding http://www.rtl-sdr.com/rtl-sdr-tutorial ... te-images/. But you could just ignore the decoding, and measure the center frequency of the signal. Then deduce the orbital parameters from that.

For NOAA you won't need antenna pointing. Just get a good QFH, turnstile or V-dipole antenna set up on a roof, and have an RTL-SDR dongle with a TCXO, and you're good to go.
This info will give us a tremendous jumpstart, thanks! Though, as far as I can tell NOAA satellites are the ones which are just for America. I assume tracking weather satellites for Europe will also have noticeable doppler shift and same procedure?

rtlsdrblog
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Re: Recieving signal from any flyby satellite

Post by rtlsdrblog » Sat Mar 11, 2017 9:38 pm

NOAA are American satellites but they pass over the entire globe equally. If you look in Orbitron you'll be able to determine when they'll pass over your location. Happens a few times a day.

Paixillation
Posts: 4
Joined: Fri Mar 10, 2017 7:15 pm
Location: Ankara, Turkey

Re: Recieving signal from any flyby satellite

Post by Paixillation » Fri Mar 24, 2017 7:19 pm

rtlsdrblog wrote:NOAA are American satellites but they pass over the entire globe equally. If you look in Orbitron you'll be able to determine when they'll pass over your location. Happens a few times a day.
Hello its me again,

From the leads you have given us, we were able to build a V-dipole antenna and we recieved simple satellite images. Since our aim is to determine a doppler shift, at this point I'd like to ask that how can we record frequency of those NOAA satellites? Any specific software or its doable by SDR#?

Thanks in advance, good day.

9a4qv
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Joined: Fri Aug 30, 2013 1:41 pm

Re: Recieving signal from any flyby satellite

Post by 9a4qv » Sat Mar 25, 2017 5:39 pm

The NOAA birds are not the best option for your experiment due to multiple carriers and wide signal.
The better option is to monitor the HAM satellites, LEO where the narrow signal from the beacon they are transmitting can be monitored for the dopler.
You can record the complete pass using the SDR# recording the IQ where you can later load the same recording and analyze it.
Even better, you can share the file so same recordings may be analyzed by more people.

There are many active HAM radio satellites where you can play with the dopler.
Of course, the ones transmitting on the 435 MHz will have 3 times bigger dopler comparing to the ones transmitting on the 145 MHz.
You can find the list of active HAM birds together with the frequencies on the AMSAT pages.

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