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RE: TVI/RFI Reduction. Empirical Results
> Original Poster: "R.E.Burnett" <R.E.Burnett-at-newcastle.ac.uk>
>
>
> Hi Michael and all,
> Out of interest is the new cap of the same kind as the one which broke,
> i.e. MMC, rolled poly, or is it made differently ?
It's the same as before, just a slightly more compact arrangement. It is
a flat-plate PE/Foil cap. Construction details at
http://www.access1-dot-net/mycroft
Follow the links to the capacitor construction page.
>
> I came to the conclusion that the gap is the "cause" of the really high
> frequencies, did you change anything there ?
Absolutely nothing. Well.. except for the wiring (strapping?)
>
> You said you added chokes and resistors, did you use any bypass caps ?
No bypass caps, but the chokes are 6"long x2" diameter 28AWG air core,
and the resistors are 1K 60W wirewounds. Unfortunately I need to change
my resistors, as they get bloody hot right now. (I suspect they are running
at around 20W average, but peak?.. not sure since I don't have the current
instrumented yet)
>
> It is a pity that you didn't have time to find out which fix did the
> trick, but it sounds like you have a much "quieter" coil for your
> efforts !
I'm sorry too. But the fourth celebration needed some fireworks :)
And I really didn't enjoy the thought of deliberately causing
RFI just to find out what brought it back. Especially since the coil
was now doing 20% better for the same power input
>
> You said that you still get a few lines on the TV. Have you tried
> recording a broadcast, and freezing a frame when you play it back.
> I found that the horizontal lines were formed of dots at a regular
> spacing across the screen. It would be nice if someone could
> independently confirm this.
I'll think about it...
Michael Baumann
Coiler, Homebrewer, Nerd. mycroft-at-access1-dot-net