RE: rc transmitter/reciver
I'm going to push this over to the radios forum where you might get more expert opinions.
It's been quite a while since R/C radios in kit form have been available in the US, but there were several back in the day. I believe there was a "Heathkit" or "Heath Kit" set many years ago. You might be able to find someone with the schematics from one of those.