The only VHF transmitter that I've made for about 30 years was my FM transmitter a few months ago that works pretty well. I was fixing a lousy transmitter made by someone else and copied bits and pieces from Rod Elliott's site.
One of these days I'll get into surface-mount parts and make some tiny stuff.
Hee, hee. :lol: Like the Keys Finder my daughter got on sale for 6 bucks. "Dad, can you fix this? It goes off all the time." Hee, hee. :lol:
I can't make it beep if I scream or whistle loudly. I clap my hands and jump on it and it's quiet. My daughter, wifey and TV make it go all the time. It makes Morse code beeps like SOS or something, 5 times.
It has a piezo beeper/microphone, a red LED, two surface-mount resistors and a black blob for its IC. It has two button battery cells.
I was going to make one with real filters and stuff so it works properly.
Now the Chinese are selling this junk.