Peter asks:
"Which leads me to avoid wood where there's any RF on it or field in it. Has
anyone ever used the old fashioned open wire line (unmatched) where the
spacers
are dowels boiled in paraffin wax? How did it stand up at US power levels?"
While in high school, I was a member of a club that participated in field
day. One day, they decided that they needed a rhombic pointed to the east
coast. I was elected to make the feedline, using dowels and boiled in
parafin. I made 200 feet of beautiful feedline using the parafin enriched
dowels. I then went up to the field day site and spent two days climbing
trees and installing this gigantic antenna 60 feet in the air. But, when I
went to install the termination, I noticed that it was a giant wirewound
resistor. I asked the old timer who I assumed was smarter than me and he
responded "it says non-inductive, so it is ok". I also questioned the use
of a rhombic on field day, since it was not a good antenna for working
stateside. I was ignored.
When field day arrived, we fired it up. However, the Mosley tri-band beam
mounted 10 feet above the ground worked much better. I again questioned the
non inductive resistors, but was ignored, because I was a punk kid.
The antenna sat idle. Afterwards, the beautiful 200 feet of open wire
feedline was coiled up and stored - where it sat until probably finally
thrown out - never used again.
I later found out the term "non-inductive" was often used in wire wound
resistors for power supplies - which meant non-inductive for ac purposes.
They were still wire wound resistors.
That was the last time I boiled dowels in parafin. I did want to boil the
old timer in parafin, though.
73, Colin K7FM
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