[Amps] KK5DR's ferrite loaded plate chokes.

[James Colville]

I just wound an ameritron look alike with #28. It's larger than they use. I
have an original ameritron choke to compare with. I think they must use #29.

My resistance was lower using #28 and it was less uH.

73
Jim W7RY



On Sat, Jan 16, 2010 at 6:59 PM, Jim Thomson <Jim.thom at telus.net> wrote:

> 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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