I built 8 digit frequency counter using Vector wire-wrap technology, but my front end design had poor sensitivity.
Then, for the science fair, I designed & built a simple TV transmitter, with horizontal & vertical retrace counters and end-of-frame equalization generator. I obtained a still-functioning Plumbicon camera tube from a local TV station, and proceeded to build a camera frame around it, using deflection coils from an old television set, and a home-brew high voltage power supply using a tube-type TV’s power transformer. I was unable to get the camera to function, but I was able to generate a raster that I could sync a black-and-white television to!
Later, I developed “TV typewriter” using TTL logic, hand-drew schematic on large sheets of paper, but once I was introduced to the PC, that fell by the wayside.