Topband: 160 GP Choke

[Jim Brown]

On Mon,9/29/2014 7:00 PM, Mike Waters wrote:
> >From p. 33: "With RG-6, RG-8X, and RG-59, use 7 turns through five 2.4"
> o.d. #31 toroidal cores."
>
> Looks like it could stand one more core and one more turn, if I only used
> it on 160 and 80.

You must have an old version of it -- the latest is summer 2010, and 
that sentence is on page 35. Yes, one more core and one more turn.

In private email, I recommended one of the bifilar chokes wound on a 
single core with enameled wire.  See measured data on page 34, and 
recommendations in the "Cookbook."

As Tom has noted, with resonant radials, there's not much common mode, 
so power handling is not a big deal. I suggested 16 turns (x2) of 
enameled #12 connected as parallel wire line. I'm using #12 THHN on my 
120 ft high 80/40 dipoles. The soil here is very poor, so my VNA 
measurements translated up the line to the antenna yield Z of about 85 
ohms at resonance, and that's the approximate Zo of the THHN chokes. The 
enameled are close to 50 ohms.

73, Jim K9YC