[Amps] construct ferrite "line isolator"

[Carl]

When the Snap Ons first came via Yuri in Canada out they were a 43 type of 
mix. Soon RatShak and others copied them and they were reportedly somewhere 
around a 61 mix. Ive never used them and have no idea whats sold these days.

Ive used FT-240  and smaller size in 31, 43, 75 and 77 mix for various 
problems or actual applications as well as beads from transistor lead size 
to ones 1.5" long that RG-213 size coax fits thru.

A 6 mix iron powder is good for 6-10M, I use it as the L in the input pi 
network for amps. If it works for you for HF RFI than thats good, Id guess 
it wasnt too severe and just a little bit of impedance did the job.

Carl
KM1H


----- Original Message ----- 
From: "Bill, W6WRT" <dezrat1242 at yahoo.com>
To: <amps at contesting.com>
Sent: Tuesday, October 26, 2010 2:06 PM
Subject: Re: [Amps] construct ferrite "line isolator"


> ORIGINAL MESSAGE:
>
> On Tue, 26 Oct 2010 11:44:03 -0400, "Carl" <km1h at jeremy.mv.com> wrote:
>
>>
>>Powdered iron is fine for tuned circuits and high power HF baluns where 
>>low
>>loss is needed. Even Sevik woke up to that fact.
>
> REPLY:
>
> I know every situation is different, but over the years I have used
> literally dozens of those "snap-on" ferrites with almost no success at
> all. I have tried both the two-piece rectangular and the clamshell type
> but I don't know what mix they are. Perhaps a different mix would be
> better.
>
> On the other hand a single moderately large powdered iron toroid has
> always worked without fail.  I use Palomar's mix #6 (yellow) in about a
> two inch diameter and wind as many turns through it as will fit,
> typically about 10-12 turns for smaller wires. Excellent results.
>
> Please note thatI am talking about RFI problems in the shack, not high
> power baluns for the transmit coax.
>
> 73, Bill W6WRT
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