22/08/2005 – Further tuning.
I gave the coil a lengthy run to see if anything blew up, and it didn’t !
Then it was time for a full power run, chair was moved back a bit 🙂 and the knobs were all twiddled to their relative maximum settings, it’s not simply just a matter of whacking them all up to max, as this power supply could easily blow the tube.
The output was nice and hot and noisy with 3 – 4 inch streamers. But overall it was not realy good enough considering that the setup was burning a horrendous amount of mains power ! Time for some fine tuning.
The primary coil was raised up 2 inches and the connections reversed. This time it managed 4 – 5 inch, sword-like streamers using much less power, so I can eventually push it even further. The downside was that it made it harder to adjust the oscillator into resonance, but is was still possible and, once there it was stable.
This was much more satisfying, it was also much louder !
The radiating power of this coil is quite impressive too, an open oscilloscope lead can easily pick up 50v of radiated RF power at over three feet away, fluorescent tubes glow brightly two feet away and my calculator blew itself up while I was sitting there trying to work out the power figures ! (sadly, it never recovered)
This is basically an AM radio transmitter, which bungs out large amounts of noise at around 450kHz, so it’s probably not a good idea to run it for long periods 🙂