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Registered Member #3974
Joined: Mon Jun 27 2011, 06:50PM
Location: Germany
Posts: 23
This isent a question, its just an observation i made on my FU-811 VTTC.
i tryde some values for the tank cap on the coil and observd the output.
2nF Vary short sparks, fast redening plate sorry no video 680pF Long Sparks ~ 4 - 5", Redening plate (~ 5 - 10 Secends at 1800V AC) 460pF quit long sparks ~ 4 - 5", fast redening plate (7 Second at 1800V AC)
video of the 680pF cap:
Rev: 2
Rec: 3: new topload, blunt nail?
Video of the 460pF cap: Rev 3.2 i used a home made one 20KV DC max. Sorry for the talking at the begining.
also the lower cpacitenc on the primary coil enables the coil to operate at lower input voltages.
sldo my tube has some burn marks on it from my extensiv testing. :( im gana retire the tube to my colection soon.
hope some of you can use this infermation that i have gatherd.
All of those tests were done without tuning. i hope the tube wont heet as fast once its tunde. Also my filament transformer gets reley hot reley fast.
Registered Member #3885
Joined: Sun May 15 2011, 12:47AM
Location: Newton, Massachusetts, United States
Posts: 94
Prof. TeraVolt wrote ...
All of those tests were done without tuning. i hope the tube wont heet as fast once its tunde. Also my filament transformer gets reley hot reley fast.
Unfortunately, if you didn't retune the coil for each capacitor, then I don't think you can really conclude anything about the effect of the value of the tank capacitor on the spark length of the coil. As the previous commenter pointed out, the frequency was different every time, so the variations in spark length were also influenced by how well-tuned the coil was with each capacitor. The only thing your experiment proved was that your primary tap is set up such that a lower capacitor value brings your primary resonator closer into tune with your secondary resonator.
Registered Member #3974
Joined: Mon Jun 27 2011, 06:50PM
Location: Germany
Posts: 23
well ya, but i got the coil tunde so, using a 680pF ceramic capacitor (not rated for RF use) and it works great for a feu minuts, untill the cap burns up, LOL. i may do some experaments later this year using diferent caps and retuning the coil for each value.
but for now i dont have time for it. im working on my AM VTTC.
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811A VTTC - lower Tank is better? Observations
