[Amps] KK5DR's ferrite loaded plate chokes.

[Jim Thomson]

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From: "Missouri Guy" <n0tt1 at juno.com>
Sent: Saturday, January 16, 2010 8:22 PM
To: <Jim.thom at telus.net>; <Amps at contesting.com>
Subject: Re: [Amps] KK5DR's  ferrite loaded plate chokes.

>
> On Sat, 16 Jan 2010 18:59:18 -0800 "Jim Thomson" <Jim.thom at telus.net>
> writes:
>> 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 ??
>
> Yes, wrong stuff to use.  As an experiment, I made a much smaller choke
> using #43, then measured the reactance with a small current flowing
> through the windings.  The reactance dropped dramatically!
> Then I used a powdered iron core and that made a huge
> difference, with almost no reactance decrease at all.

##  well, that  IS  a  stunning revelation.

##  I was sure powdered iron  might  be the ticket.
 Powdered  iron has less mu, so it wouldn't provide as much uh.
Perhaps  #2  mix would work. [ red cores]  I don't think u can get #2  mix 
in rods though ?
#2 is used in tank coils.. like  T-225-2B, etc.    Still, it might provide 
enough MU, to do the job,
but I doubt it.   The stock coil  couldn't be much more than 45-50 uh [ so 
1st series resonance >35 mhz]
The #2 powdered iron [ or another type of powdered iron mix]  would have to 
have enough MU, to increase the
uh  up to at least  150uh.  Perhaps if you had enough of it stuffed in 
there, you could get the 150-180 uh.

##  For a good  laugh, check out  KK5DR's  ultimate....  'choke  resonance 
test setup',
complete with scope, sig gens etc, it's on his site.   That set up is 
totally flawed, and got trashed on
the other amp reflector months ago.

Later... Jim  VE7RF



>
> 73,
> Charlie, N0TT
>