On 10/9/2010 1:09 PM, jimlux wrote:
> You want to look at K9YC's write up for details, but I use 2.4" #31
> toroids for pretty much everything (since I have a whole box of them) I
> haven't tried them at 50 MHz, though.
For 50 MHz, you want two or three turns through a 1-inch long core and
two turns through a 2-inch core,. and for maximum noise suppression, you
will want at least three of these multi-turn chokes in series along the
line, close to the feedpoint. The reason you need multiple chokes in
series is that you only need 2-3 turns to put the resonance at 50 MHz,
so you haven't got much benefit from N-squared. Fair-Rite #43 and #31
are roughly equivalent at 50 MHz.
73, Jim K9YC
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