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Re: Topband: FairRite Products 2873000202

To: <W2pm@aol.com>
Subject: Re: Topband: FairRite Products 2873000202
From: "Andy Ikin" <andy.ikin@btinternet.com>
Reply-to: Andy Ikin <andy@wellbrook.uk.com>
Date: Sun, 5 Feb 2006 13:19:29 -0000
List-post: <mailto:topband@contesting.com>
"I have been using no.27 enamel wire with only the secondary within a teflon 
tube in the core. 
The primary is wound around the telfon but clearly touches the bare core -- are 
you saying this is not good?  Pete W2PM"

Pete, I hadn't bargained for such response to my posting; 

However, Tom's posting puts the issue into a correct prospective

"You should avoid scratching through the enamel, especially
if the core contacts another conductor.
Normally enamel is not a problem, but at times if a single
layer of enamel is used it can be scratched through.
Actually you don't want to scratch the wire with ANY core.
The reason is pretty obvious, that bare spot might touch
another bare spot in a winding (which is worse than core
contact). Changing to 43 material does not totally solve the
problem."

My experience is based on the use of these cores in receiving antenna 
applications ( low noise transformer feedback amplifiers ), over the past 9 
years I have wound thousands of transformers using two hole type 43 material 
cores and to my knowledge no failures have been attributed to either shorted 
turns or wires touching the core. However, I have recently noticed that some 
Fair-rite cores ( made in Red China ) have a rough surface compared to US 
manufacture, I have yet to determine whether this may be problem!!!

73s

Andy  Ikin G8LUG
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