Last weekend I obtained the dish on ebay - C-band mesh for satellite reception, for $160 (just a 2.3m dish, no electronics.. still a good buy because it is easy to assemble the contraption in a backyard).
Then I stumbled on this website:
http://www.haystack.mit.edu/edu/unde...srt/index.html
This is almost exactly what I had in mind.. I am not the first one here ;-)
Currently I am still building the LNA and BPF filter
For the receiver and recorder I will use
SDR# and SkyPipe.. I tried it in a dry run, and it works OK (RAW signal, my audio card passes DC signal to recorder it seems..)
Anyway, I am hoping to at least detect the 21cm line, and it seems it will be possible to even do some Doppler measurements (I have high stability frequency reference, so it won't be hard to calibrate the TV stick properly).
Today I simply couldn't resist to preliminary assemble the dish..
First, I thought I will be able to mount it on EQ6.. but it's too cumbersome and too heavy (13kg of what's on the image below, plus I would need a counterweight.. too much).
Feeder is made from one of my wife's unused pots (7" dia, 3" deep - ideal!)
Antenna is helix, 2 turns of 4mm wide copper tape, wound and glued on 68mm dia pharmacy box (krill oil, I think.. on the image near connector (SMA) you can see the matching section, 22mm 75ohm cable plus 4nH of wires - measured return loss is >10dB at 1420MHz).
All in all, getting there...
EDIT: after playing with RFSim99 a bit, I (theoretically) managed to improve the matching (pic attached). It's much more broadband with additional 75-ohm shorted lamda/4 section in parallel to connector.