Building an amateur satellite radio with gnuradio


I’m looking for some advice on what parts to buy from Minicircuits
for my particular application. I am looking into using GNU Radio and
the USRP (v1) to make an amateur satellite radio suitable for 9600 bps
(data-only) communication with the AO-51 Echo amateur radio satellite.
I’m focusing on building a radio that transmits on 1268.700 MHz and
receives on 435.150 MHz, so I know I’d need two daughterboards for the
USRP – the RFX1200 and the RFX400. respectively. I am looking for at
least 10 watts on the L-band uplink from what I can tell from the
AO-51 email list.

I have gone to the Minicircuits site, but there are so many
amplifier parts, VCOs, etc, and have no idea what I would really need.
I think I’ll need a preamp on the receiving antenna, and an amplifier
on the transmitter side, but I don’t seem to see any “preamplifiers”
on the MiniCircuits site at all, so I can only assume that
preamplifiers are just amplifiers with a few special characteristics.
And there are amplifiers that cover a much wider band than I really
need, so I’m not sure what I might need.

I was actually surprised to find some GNU Radio software that
implements the G3RUH modem for 9600 bps data communication ( ), so I think I’ve
got something to start with there.

Any help would be appreciated.