Towertalk
[Top] [All Lists]

Re: [TowerTalk] add a 3rd el to 40-2cd

To: towertalk@contesting.com
Subject: Re: [TowerTalk] add a 3rd el to 40-2cd
From: "john@kk9a.com" <john@kk9a.com>
Date: Wed, 14 Mar 2018 07:25:16 -0400
List-post: <mailto:towertalk@contesting.com>
The low-Q loading coils probably contribute to the 250KHz SWR bandwidth
that K7LXC posted.

John

From:   "Jim Thomson" <jim.thom@telus.net>
Date:   Tue, 13 Mar 2018 20:44:36 -0700


##  The main problem with the 402-CD is the loading coils.
http://www.qsl.net/ve6wz/intro.htm  scroll down til u see the info on the
XM-240.
http://www.qsl.net/ve6wz/CC_coil.html   12 gauge magnet wire, wound butt
tight,
 on a .75 inch solid fiberglass rod  is as useless as it gets for a
40m loading coil.  Q is through the floor..and coil losses are sky high.   No
wonder they end up with a 50 ohm input Z..with NO matching  device used.
The XM-240 is a direct fed  2 el  40m shortened yagi.   When was the last
time
you saw a 2 el yagi that did not have a way less than  50 ohm input Z ?
The coil losses are sky high on the inferior  designed coils, such that the
real feedpoint Z  plus coil losses = 50 ohms..... = fubar.



_______________________________________________



_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk

<Prev in Thread] Current Thread [Next in Thread>