I built my first repeater by modifying a Pye repeater (made in the U.K.) to the 2m ham band. Had to change a lot of stuff, and the transmitter used tubes (5894 final amp). But it worked.
Probably put 500 hours into that, to get it working properly, de-bugged, and de-noised.
Might have been cheaper to buy a brand new commercial Motorola repeater, when I think about it...
When I had a split-site machine (2m) for a while, the RX location was better than the TX location so I built a 4X150A amp for the TX, so it could run about 200W output power. That was a great experience and it did help "level" the coverage since it was split-site. I'd never recommend anyone do that.
A government which robs Peter to pay Paul can always depend on the support of Paul.
-- George Bernard Shaw