That's a judgement call that I wouldn't argue with. Choke guidelines for
RG400 would apply.
73, Jim K9YC
On 2/19/2019 8:48 AM, john@kk9a.com wrote:
I think RG-302/U would be a better 75 ohm PTFE coax choice.
John KK9A
Jim Brown K9YC wrote:
After some discussion on one of the reflectors about chokes that could
be used in 75 ohm phasing lines, Grant, KZ1W, sent me some. I wound a
bunch of chokes using the same methods, and on the same cores, used to
produce the new Cookbook, and added winding guidelines for these chokes.
They have been added to the latest version of k9yc.com/2018Cookbook.pdf
Refresh your browser to make sure that you've got the latest version. If
you have the latest, you'll a a photo of a choke wound with white
miniature Teflon coax on page 3.
Note that RG179 has much more loss than RG400, so they have a lot more
differential mode dissipation for the same power level. They MUST be
exposed to air so that they don't overheat. If used in this manner, they
are probably sufficient for use in a 4-square in which power is equally
divided between the four antennas, running at legal limit.
What looks like new old stock RG179 is plentiful and cheap ($0.35 -
$0.50/ft) on the big auction site from vendors with 100% ratings.
73, Jim K9YC
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