I agree, the Cushcraft loading coils are pretty inefficient and it is
probably why the SWR bandwidth of their 40 shorty is so good. OptiBeam,
JK and Force12 make very nice High-Q 40m coils.
John KK9A
To: <towertalk@contesting.com>
Subject: [TowerTalk] Another Cushcraft shorty-forty question
From: "Jim Thomson" <jim.thom@telus.net>
Date: Fri, 7 Aug 2015 07:06:30 -0700
Date: Thu, 06 Aug 2015 20:02:29 -0400
From: RMorris <robrk@nidhog.net>
To: George Dubovsky <n4ua.va@gmail.com>, kz8e@wt.net, towertalk
<towertalk@contesting.com>, Tim Jellison <kl7wv@kl7wv.com>
Subject: Re: [TowerTalk] Another Cushcraft shorty-forty question
## another option is to toss the 68 turns of 12 ga magnet wire used to wind
the oem coils..and replace with
3/16 inch Al tubing coils. 8 ohms vs .8 ohm.
http://www.qsl.net/ve6wz/CC_coil.html If cu is used, it drops down to .5
ohm.
## Ken at W3JK, uses .25 inch solid AL for his 40m coils..then just uses AL
standoffs at each end of the coil...
similar to what F-12 used on there yagis. The .25 inch al solid coils are
stuffed into the .25 inch hole at the end of the
al standoff....and protrude a bit out the other side. Then just tig or
heliarc
wled em. Solid connection, zero ohms.
3/16 solid AL could also be used.
## I used .375 silver plated CU tubing to replace the LL rods on my F12
340N.
.07 ohm per coil.
## IMO, the oem 12 ga magnet wire that CC used on solid fiberglass has
way too
much loss for the loading
application.
Jim VE7RF
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