Re: [Discuss-gnuradio] How to use USRP to detect and collect weak satellite signals

[Sylvain Munaut]

Hi,

> 1. USRP N210, DBSRX2 800-2400MHz
> 2. Minicircuit cable amplifier, provides 37 dB gain at 15V/0.68A supply
> input. To ensure signal is enough enhanced, I used two of them in recent
> experiments.
> 3. Horn antenna with frequency range from 0.8 - 18 GHz. beamwidth 60 degree.

You probably want something more directional and a more restricted
frequency range to get more gain.
Also if the satellite signals you want to receive have any kind of
polarization, you want your antenna to be matched to it.

Since they're LEO and, well, moving you actually might need a tracking
antenna and the software to drive it.

Then you need FILTERS ... the most narrow and high selectivity you can
find that fits your frequency of interest.
If you're trying to listen to very weak sat signals but at the same
time you have only a few hundreds MHz away strong GSM carriers, stuff
if going to saturate with all the gain you're putting in, so you need
filters.

Finally what's the exact model of amplifier you used and what kind of
NF does it have ?


> And then I turned it to 1.57542 GHz,
> which is the L1 band of GPS, it also shows nothing but noise.

Yeah, seeing GPS is not easy, signals are well below the noise floor AFAIK.


Cheers,

    Sylvain