Ed G wrote in
. 192.196:



After some additional Google research, I found them. Made by
Fair-
Rite Products Corp. PN is probably: 2643806402. Product
description matches unit on hand, and lists it as type 43 material
with a Z around where I want to operate of about 20 ohms.

My guess is that you got the 20 ohms (for an unstated intended
frequency of use) by extrapolation of the published data from 10 to
250MHz. You probably also read that the core material is recommended
for 25 to 300MHz. Both of these would suggest that the material is not
the best for your intended frequency, whatever that is.

So, for an effective choke, you may need 25 to 50 of these things.
They are only a half inch long each, so that is just 13 to 25 inches
in length in total, not unusual for that type of choke.



Actually, since I probably will be using RG8X I can most likely
loop a couple turns through each bead... which should preclude the need
for quite as many.

Am I right that this is a very short length of coax in a vehicle, and the
VSWR will be low due to the ATU at the feedpoint, and that the ATU ground
/ coax braid will be connected to the vehicle metal framework? So why use
thick coax? Why the choke?

If you need a choke, you could get some cores that are a neat fit over
RG58, at 10MHz appropriate type 31 cores has a Z of 115/inch. That
doesn't address the issue of whether the power / control connection needs
protection.

Actually, I am not sure why you are doing this anyway, is it just in case
or is there a demonstrated need?

Owen