In a message dated 2/5/2006 11:06:28 AM Eastern Standard Time,
andy.ikin@btinternet.com writes:
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
Thanks Andy - and all the others. I have made 5 of these based on Tom's
designs shown on his site and ON4UN's new book and so far no issues with the
non
protected 1 turn primary. However, I semi-pot mine by putting a dab of epoxy
on each end of the transformer which not only keeps water out of the holes but
keeps the wires tight. And I like to pull the turns tight so that I can
effect maximum physical separation of the windings. Perhaps I'll find a larger
teflon sleeve for the holes and also continue to use the smaller teflon tubing
within that.
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