[Amps] Tips For Winding a Plate Choke

[Jim Thomson]

Date: Thu, 10 Oct 2019 08:35:48 +0700
From: Martin Sole <hs0zed at gmail.com>
To: amps at contesting.com
Subject: Re: [Amps] Tips For Winding a Plate Choke

<Carl,

<Did you notice any effect on 10MHz. When I put an Ameritron choke in my 
<78, which I agree fits just fine, it was okay but went bang on 10Mhz. 
<Had I the time then I would have investigated moving it to resonate 
<somewhere else but in stock form mounted in the 78 I measured resonance 
<at 10.5MHz, too close to 10.1MHz to work I think.

<As a more general question, where would be good to place a single choke 
<for 160-10 9 band coverage, around 12 MHz?

<Martin, HS0ZED

##  The  RF  parts /  Ameritron  choke  resonates  at  12.5  mhz.....and  27  mhz.

##  There  is  no  way  to wind  a   single  choke..with  200+ uh....  that will only
have one resonance.   They  will  always  have  two  resonance points. 

##  50  uh is  fine  for  80-10m  amps.   On  paper,  100  uh  should  work
on  160-10m.   But  your typ  90   choke  will  resonate just  above  15M. 
A  100  uh  choke will  resonate just  below  15M.  Its  tough  to  park
resonance points  between  ham  bands.

##  I  think  its  only  the  usa  that  has a 200 watt  limit on 10 mhz  band.
750  watts  out....  measured at the  ant...here  in  Canada.

##  IF  u  removed  turns  from  the  very  top  of  the  rf  parts /  ameritron  choke,
it  would probably shift the  27  mhz  resonance up  higher....like  10m band.  It may or
may not shift  the lower  resonance  point  upwards. 

Jim  VE7RF