Topband: Disappearing toroid
Jon Zaimes AA1K
jz73 at verizon.net
Thu Sep 10 18:24:01 PDT 2009
With the new season starting to get into swing, I discovered a few days
ago that my phased JA Beverages (each 935 feet long, spaced 175 feet
broadside) were not functioning. Since a JA was hearing me today, but I
couldn't hear him, I figured it was time to get things working.
When I walked the wires this morning I discovered that a tree had busted
one wire about halfway along its length. The feedpoint transformer on
the one element looked fine (which happened to be the one with the
busted wire). The terminations on both looked fine.
But the feedpoint on the other was perplexing. The insulated coil wires
were still in place, looped just as I had wound them on the BN-202
binocular core several years ago. But the core itself was gone! I
scoured the ground below but could find no pieces of the ferrite --
though since this is in a woods they may have been buried by pine
needles and leaves.
While I thought a lightning strike might have vaporized the core, I
would have expected there to also be damage to the wires. But there is
no evidence of this -- the insulation appears undamaged, no blackness or
other sign of being "cooked." I did have some minor lightning damage in
the shack a few months ago -- the first in nearly 12 years at this QTH.
So I'm wondering if any others have had this experience with a BN-202?
I have spare cores so will just wind a pair of new transformers to be
sure -- and check out the terminations with an ohmmeter too.
More information about the Topband