I never got to play with it much because the first time I fired it up, the 6A3 plate started to get red and just about that time my father came into my room and told me to stop whatever I was doing because it was tearing up the TV reception. Later I showed him the project in the book and we talked about it and he told me that you can't just swap any tube for any other tube, 400 was way too much voltage for that, I best follow the directions exactly until I learn more about it, and 'no more transmitters' until then. I was disappointed until the week after, when I was presented with a tube substitution book from radio shack, as well as an old RCA tube manual and a few junk AA5 radios and used tubes he'd gotten from a TV repairman friend of his. Still no transmitters but lots of other things to make.
That sure brings back memories! I made a device to test for Hertzian waves, a coil consisting of 4 turns 3/8 copper tubing, about 4 inches in diameter, with a variable capacitor and a 7 watt Christmas tree bulb as an indicator.
For the exciter, a pair of 6L6s in a push-pull oscillator, with a similar plate coil and a split-stator variable. It had a 4 amp 6.3 volt filament transformer, but the plate voltage was raw, unrectified, unfiltered 120 volt AC direct from the line. The feedback to the grids consisted of a piece of teflon wire strung through the coil tubing.
When I placed the detector coil within a foot of the exciter, I burned out the Christmas tree bulb when tuning the capacitor. I also found that when placed near or in the coil of the exciter, it would illuminate the full length of a 40 watt fluorescent tube. I have no idea whether or not the plates were glowing, as they were metal 6L6s.
I had no directions to follow, but just put it together from ideas when reading other circuits. But it did wreak havoc on the old black-and-white, and was ordered disassembled.
That was very disconcerting to a 9-year-old! But at least I felt certain that I had confirmed the existence of Hertzian Waves!