[Amps] 2 x 3-500Z filament choke + 30/60/80A fil chokes

[Carl]

----- Original Message ----- 
From: "Jim Thomson" <jim.thom at telus.net>
To: <amps at contesting.com>
Sent: Wednesday, December 07, 2011 3:37 AM
Subject: [Amps] 2 x 3-500Z filament choke + 30/60/80A fil chokes


> ** I dont know where you are getting 43 mix rods Jim since Fair-Rite 
> doesnt
> make them.
> The 33 mix is the choice plus it is temperature stable to a high degree.
>
> ###     http://www.surplussales.com/Inductors/FerRods/FerRods.html  at the 
> very bottom.
>
> Dunno where sson gets em from.  They have gone way up in price too. They 
> had em
> on sale several years ago, so I got just enough spares for one more 
> project.
> These are 1/2"  diam x 8" long..and are type 43 rods.  2 of em...+ 8 or 10 
> ga magnet
> wire, paralleled in the fashion I described works fine on 160-10m...and 
> will easily
> handle 60/80 A CCS.
>
> ## since at the time, those 12" long x 1"  diam rods were no longer 
> available, we had to
> go to plan B.  John Lyles suggested to me to  use 2 x rods, each bifilar 
> wound, then parallel
> the windings, but it has to be done correctly.   Parallel any one winding 
> from rod A...with any
> one winding from rod B.....and vice versa.    What baffles me is the uh 
> does not drop in 1/2,
> like you would think it would.   It does drop to 73% of it's original uh. 
> In the case of the 10 ga
> magnet wire set up, each winding is 52 uh....and drops to 38 uh  when 
> windings paralleled as just described.
>
> ##  In any event, it works superb, and has been used in a lot of 
> amplifiers in the last few years. I wasn't
> about to trust 50A through 8 ga magnet wire on a single rod, so used 2 x 
> 10 ga's in parallel as above.
> When it came to the 79A  fil choke, we thought, yikes, now what do we do. 
> Tried the same stunt, except
> used parallel 8 ga magnet wire.  Both of em are tried and proven from 
> 160-10m.
>
> ##  Now who the heck made that giant 12" x 1"  type 33  rod u used to sell 
> ?   Is it still available?   I checked
> all over the place several times years ago..and could never source it, so 
> gave up... and went to plan B.
>
> Later... Jim,  VE7RF


** Since SSN doesnt list a manufacturer and 43 mix is proprietary to 
Fair-Rite I suspect its BS. Call Fair-Rite and ask them if they ever made 
such a rod.
$35 for WHAT?? Why didnt you just get 33 rods at $20 from Amidon? I sell 
them at a bit less.

The 12" rods I sold you back then were from Fair-Rite and were 3/4" 
diameter. They quit production around 1990 due to poor yield if its to be 
believed.

Ive also used large 43 beads (the type that slip over RG-213, etc), 1"x 1" 
and epoxy together for some serious rods for both big tubes and also for use 
below the BCB. Yes, that winding method works well; I dont remember where I 
heard it from, maybe John back on the original AMPS forum in the 90's.

Those beads also can make for serious binocular cores.

Carl