[Elecraft] K2 Binocular Core
Ron D'Eau Claire
rondec at easystreet.com
Mon Sep 27 20:00:40 EDT 2004
I'd like to add an addendum to my earlier post on this subject:
I happened to talk with Eric today and he said they don't really recommend
"interleaving" the wires on the binocular core although it doesn't seem to
hurt and may help.
I was just upgrading an older K2 for a buddy and noticed that it only
produced about 7 watts on 10 meters. I pulled T2 and rewound it with the red
winding spaced out over 85% or so of the core and the green secondary spaced
out over almost all of the red winding (the green wire wraps between
adjacent red turns for as long as it goes - it's a smaller winding than the
red wire one), then carefully dressed the leads so the green turns didn't
get jumbled up in a bunch and the core was about 2mm off of the board. That
produced the full 10 watts on 10 meters and up to 15 watts on some of the
lower bands.
Neatness counts! It's easy to make the green windings jumble up on that coil
if you pull on the leads when soldering them. Besides, it should be spaced
slightly off of the board. I put a little piece of scrap plastic as a spacer
under the coil until it was soldered, then slid the spacer out.
Gary at Elecraft has an excellent photo of a properly-wound T2 on the
Elecraft web pages. Look under Builder's Resources/Troubleshooting Tips -
the second from the bottom of the list I believe.
Ron AC7AC
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