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Re: Very low Fo Coils (was:not so scary idea)



> Original Poster: Ed Phillips <evp-at-pacbell-dot-net>

>         Here are a couple of secondary designs which should work; the
> parameters given are for no top-loading toroid.  With one the windings
> wouldn't need quite as many turns.  The primary design is left to the
> reader, but should be no big deal since it could be excited CW from a
> pole pig.
> 
> SMALL COIL:
> 
>         Diameter                50 feet
>         Length          150 feet
>         Wire size:              #18
>         Turns                   42,755
>         Inductance              7948 henries
>         Capacitance             873 uufd
>         Wire length             6,715,993 feet
>         Weight          33,446 pounds
>         DC resistance   42,882 ohms
>         Estimated Q             70
> 
>         If that Q seems a bit low try:
> 
> BIG COIL:
> 
>         Diameter                90 feet
>         Length          200 feet
>         Wire size               10
>         Turns                   23,077
>         Inductance              5381 henries
>         Capacitance             1400 uufd
>         Wire length             6,524,846 feet
>         Weight          207,490 pounds
>         DC resistance   6518 ohms
>         Estimated Q             291

Nice coils, although their Zsec is rather high,
well over 2Megohm!  That may have to be reduced
to under 100k ohm to get suitable arc performance.
-- 


-GL
www.lod-dot-org