[TowerTalk] RG179 Chokes For TX 4-Squares

Jim Brown jim at audiosystemsgroup.com
Tue Feb 19 01:10:25 EST 2019


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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