Wookie,
At the moment I am playing around with a 90cm dish and a tin can feed. The only issue is that I have a perfect signal at the dish (-30dbm!) but the length of rg213 I am using is a little too long.

I am in need of around about 15 metres of LMR400 which should fix the problem.
I tried tonight mounting a USB client on the roof and using 3 active repeating USB cables to connect to it but it doesn't like that.
I'm not too keen to be running a spare pc in the roof so at the moment I am on hold until I can get a decent length of cable.

cheers
-John