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Re: VTTC first sound :-)
Original poster: "Ed Phillips by way of Terry Fritz <twftesla-at-uswest-dot-net>" <evp-at-pacbell-dot-net>
Tesla list wrote:
> Original poster: "Herwig Roscher by way of Terry Fritz
> Hi fellow VTTC builders,
> Today I audiomodulated of my system for the first time. I used a 20
> W car amplifier/equalizer driven by a signal generator. A 12/230 V
> mains transformer was connected between grid coil and grid leak
> combination. No other modifications were necessary.
> Connecting the scope across a 4-turn-pickup coil wound 3.5" below
> the primary, I easily could adjust the amplitude of the signal
> generator to a point, where the amplitude modulation was just 100
> %. Deafening noise forced me to use ear protection. Sweeping the
> modulation frequency I had to state, that the frequency response of
> the mains xformer (like suspected) was dissapointing. So I'm
> looking for an output tranny of a tube amplifier now.
> Still a lot of work to do, but a lot of fun as well.
Have been meaning to pass along an anecdote on audio-modulated RF
sources and arcs. I worked at Naval Research Laboratory right after WW2
(1945-1947), and one of our lab technicians has an interesting and sad
story to relate. He had been a technician at one of the big Voice of
America AM short-wave stations in Boston (WRUW/WRUL) and had managed to
walk into the 600 ohm feeder line of a 50 kW transmitter while it was
being used. Carelessness on the part of someone else, but still he was
the one who got hurt. His memory was that at the first instant he
didn't feel much, but was aware of the light of the arc. As soon as he
reacted and pulled away backwards the arc of course grew in length and
he began to hear strong audio coming from the arc to his stomach!!!! He
ended up with a huge scar on his abdomen, and that horrible memory.
Spent many months in painful recovery.