[TowerTalk] RG179 Chokes For TX 4-Squares

N2TK, Tony tony.kaz at verizon.net
Tue Feb 19 13:20:22 EST 2019


John,
Any issues with tight winding RG-302 around a 2.4" core compared to RG179
since the RG302 is a solid center conductor?
N2TK, Tony

-----Original Message-----
From: TowerTalk <towertalk-bounces at contesting.com> On Behalf Of
john at kk9a.com
Sent: Tuesday, February 19, 2019 11:49 AM
To: towertalk at contesting.com
Subject: Re: [TowerTalk] RG179 Chokes For TX 4-Squares

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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