Tnx for the update Jim...been many years since I sold a FC-30.
For any 20-30A amp I would recommend a choke made from 10' of either #12
or #10 wound over a 7.5" FT33-50-750 ferrite rod.
I goofed yesterday..the length should be 10' total, not each winding for
the RadioKit 30A
filament choke.
I sell complete kits for less than Amidon sells the rod only....$19.95
for the 30A choke.
Rod, wire , ceramic stand-offs.
73 Carl KM1H
On Fri, 04 Dec 1998 13:00:59 +0000 "Jim Thomson" <jim_thomson@bctel.com>
writes:
>Scott/Carl. The FC-30A consists of TWO bifilar chokes inside,each
>rated
>at 15 amps.Both chokes are made from #14 Ga wire.(15 amp rated wire)
>The idea behind 2 chokes was to be able to measure individual plate
>currents of a 2x 3-500/4-400 amp. This required 2 separate fil
>xfmrs,each rated at 5v-15 amps(with center tap).+ separate bifilars.
>With just a SINGLE 5v-30 amp fil xfmr,manual said to PARALLEL ACROSS
>(horizontal) lugs at each end . Thus each bifilar choke had each end
>shorted to make one effective single winding(will now handle
>30AMPS-2x14's in parallel) Hope this makes sense. BTW,some guys I
>know
>had trbl with that choke on 80m,inductance was marginal.Don't know
>what
>the diff was between a FC30 and a FC30A.I would use a reg bifilar
>made
>of 7 1/2" rod + 10 ga wire. If you have space limitations,cut the rod
>in
>half and make two separate,single wound chokes(one per fil leg). The
>inductance will be much higher than a bifilar wound choke per my
>measurements. Jim VE7RQ
>
>
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