I thought people might be interested in a recent experience. I blew the
center 4:1 balun on my Carolina Windom, which has been a very effective
antenna for 80 and 40. Took it apart, but since this reflector doesn't
do images, let me describe what I found. The balun itself is very
minimal - a single stick of ferrite a half inch in diameter and about 6
inches long, wound with two windings of #14, 300V PVC-insulated stranded
copper. I run full legal power, and frankly, I would have expected the
balun itself to have blown. There's clear evidence of overheating, a
lovely brown spot between the two leads which both go to the coax
connector's center pin, and I thought perhaps the center pin had shorted
to the shell underneath, but it is not, at least at ohmmeter voltage.
Perhaps the RF voltage at that point causes a flashover. So, the mystery
Meanwhile I have replaced it with a 5KW Balun Designs 4:1 balun
specifically intended for this type of antenna. It looks like a much
more robust design
--
73, Pete N4ZR
Check out the Reverse Beacon Network
at <http://reversebeacon.net>, now
spotting RTTY activity worldwide.
For spots, please use your favorite
"retail" DX cluster.
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|