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[Amps] KK5DR's ferrite loaded plate chokes.

To: <amps@contesting.com>
Subject: [Amps] KK5DR's ferrite loaded plate chokes.
From: "Jim Thomson" <Jim.thom@telus.net>
Date: Sat, 16 Jan 2010 18:59:18 -0800
List-post: <amps@contesting.com">mailto:amps@contesting.com>
I Checked a bunch of really old  e-mail, and notes.   The folk's  who 
duplicated the KK5DR plate choke, using  1/2"  type 43 rod, stuffed into the 
inside of a  hollowed out 1" OD  Teflon rod
had nothing but grief.   All the  rods overheated !   In some cases, the rod 
actually launched itself  out the top ! 

Either  1" type  43 rod is required,  [like several  type  43,   1" Od beads 
slid over the 1/2"  rod]....   or several  type 43 rods bundled  together. 

Perhaps  type 43  material is the wrong stuff to be using  for a plate 
choke...esp considering the  typ plate load Z's involved ?? 

Type  43....  1"  OD bead's,  slid over  393 Teflon coax makes for excellent 
Choke baluns.    The  1/2"  x 8"  long  type 43 rods  work great  for   
Bifilar's.  But in both those cases,
the Z is only  25-50 ohms.   

What would be an excellent solution,  would be a higher current version of the  
RF parts /Ameritron plate choke.  I have asked a few times  what ga  wire is 
used in the Ameritron choke,
and can't get a straight answer.   I believe it's around 28 ga.       A version 
made with 22 ga wire  would be  the ultimate solution.   I know how Tom 
designed the Ameritron choke. 
However, I'm not prepared to  sit there in the shop for months,  with a vna, 
etc,  trying to  park  resonances.    The  2 x choke + relay version was a  
cheap way to get around the problem.
Incidentally, the choke relay coil  was activated by a 3rd wafer on the tuned 
input switch. 

Later.... Jim   VE7RF 
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