Here are some Homebrew UHF Preamps that I madeThey all use low cost low noise microwave devices. The construction of them may look ugly, but they work great. I have the NE34018 UHF Preamplifier Schematic. Sorry, I don't have schematics for thr rest of these. They were based off other designs and the available parts I had. Basic design is like any GasFet/HJ-FET preamplifier but with tweaked input and output circuitry. The best success on UHF was with the NE34018 HJ-FET device. It gives excellent performance, is reliable, cheap and pretty stable. This is the device I used for repeater and satellite use.
This preamplifier is using a NE33284a HJ-FET device. (approx 18db gain)
This one is using a NE34018 HJ-FET device. (approx 15db gain)
This pre-amplifier is using a MGF1302 GasFet device. (approx 18db gain)
This a remote switched preamp. (the relay is underneath)