Have another curiosity to figure out:
A couple years ago I'd rebuilt my fathers 30 year old HyGain
tribander & replaced the traps at the same time. It resonates well at
the CW portion of the band. However, when I transmitted CW with it
the oil furnace thumped like a freshman kettle drummer on his first
day at band practice. This was bad enough it happened running
barefoot, using an amp was not a possibility. I began trying to
resolve the issue but thanks to excess whining from others in the the
house I stopped trying & disconnected the antenna.
To describe the thumping, it doesn't seem to be clicking or coming
from a relay, it sounds like someone is hitting the sheet metal
enclosure, hard & from deep inside with an open hand. When standing
beside the furnace it definitely sounds like it is coming from below
& from within the furnace itself and not the ductwork. It is loud
enough that people upstairs hear it from downstairs and think I am
pounding on something in the basement. The thumping seems to be the
same character and using more power does not make the thumps louder.
I decided to give it another try this year and thought the balun
might have been previously damaged. I was going to use 12 6" coils of
coax but was advised against that as being effective so I bought a
DXE-BAL050-H10-A and installed it. There was a marked improvement
using this balun and now there is no thumping when operating
barefoot. Using the amp though on occasion, not consistently, there
still is thumping. For instance; I just now transmitted 1500W on 10,
15 & 20 with no thumping whatsoever. Last night when I was
transmitting, there was the occasional thump.
Intermittent anything is hard enough to diagnose but something needs
addressed. Any thoughts on what I might look at first before I start
digging in?
73,
Gary
KA1J
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