[Amps] Ferrite Core for 160M PI Output ?

[Paul Baldock]

Thanks for the info Jim.

I'm working on converting and SB220 to a dual 6M, 160M amp. I've done 
lots of single band 6M conversions, so this will be interesting.

- Paul

  At 09:20 PM 6/10/2017, Jim Thomson wrote:
>Date: Sat, 10 Jun 2017 14:09:05 -0700
>From: Paul Baldock <paul at paulbaldock.com>
>To: "Amps group" <amps at contesting.com>
>Subject: [Amps] Ferrite Core for 160M PI  Output ?
>Message-ID: <593c5ff4.4bd1620a.e42b5.0bd9 at mx.google.com>
>Content-Type: text/plain; charset="us-ascii"; format=flowed
>
><When I said Ferrite I should really have said Toroidal so as to
>include Iron Powder.
>
>- Paul
>
>
>
>
>What's the best PI Output Ferrite Core(s) to use for a 1.5KW tube amp?
>
>Thanks
>
>- Paul
>KW7Y
>
>##  Powdered Iron.   #2  MIX.   These are the RED ones.
>T225-2B.   Beware, the T225-2A  is only .5 inch thick ...
>IE  laying on the table with hole pointed at the  ceiling,  its
>.5 inch tall.
>
>##  The T225-2B  is  a full 1 inch thick.    You require at least 2 of them
>for  1.5 kw out for cw  and  ssb.    For RTTY, you require 3 of them.
>
>##  these have been in use since the 70s..for  160 + 80m.
>
>##  I think marv calculated the heat at aprx 57 watts of diss, regardless
>of how many core are used.   They run hot..normal.
>
>##  If 3 used, the entire mess ends up being  2.25 inch OD  x 3 inches long.
>Bigger OD and length, once the wire is wound onto them.
>I found some air dux..which used 12  or 14 gauge wire.... and had the turns
>spaced closer than normal air dux.   Worked perfect for the 160M conversion
>project I was working on.   Zero heat vs the stack of torroids.  The air dux
>weighed nothing vs the hefty weight of the 3 stack I also tried.   The airdux
>ended up being aprx the same diam and length as the torroid stack.
>
>##  space wide, the torroid stack save me nothing.  160m is pretty forgiving,
>with long leads, coil close to cabinet side walls etc.
>
>Jim   VE7RF
>
>
>
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