There was an article in Radcom Microwave column a couple of
years back showing how to modify a Franko Sat LNB board to
produce a low noise front end for 5.7GHz .
I have one and it has around 1.5dB noise figure and 15dB
gain , which would be a good start towards a TVTR.Followed by
an ERA gaas Mod amp .
Evanescent filters are easy to make and will give you
bandpass after the front end stage .
Build/buy a synth board to provide a lockable LO for TX/RX
and bosh some i.f. passband filtering together .
Add a couple of mixer stages and some
control system/sequencing and you are there .
The Birmingham lads (G8OHM) have/had PA modules at modest
second hand prices for 8W output .
I would start with the RX and use the Beacons available
locally to you (GB3OHM on .900 and GB3ZME on .910 +/-a few kHz
Have added a 5.7GHz VE4MA to my 60cm 10GHz offset dish ,off
boresight in the horizontal - seems to have little influence
to the 10GHz LNB and just needs you to offset on your rotator
Hope to use my Kune TVTR on EME next , after 24GHz tests .
It's just stopped raining !