On 12/19/2021 10:55 AM, Jeff Blaine wrote:
For 160 something around 8+ turns & type-31 are the "right" rule of
thumb answers.
Based on my research, a lot more turns. http://k9yc.com/2018Cookbook.pdf
Pete has received lots of good advice in this thread. I'll add this.
Base loading is a bad thing, because it places inductance at the point
in the antenna that carries the most current, and should be doing the
radiating. Better to remember that SWR is NOT a measure of antenna
performance, that as Jeff has noted, feedline loss is pretty low on
160M, and that what matters for moderate values of SWR most is whether
you amp can put power into it with the help of a tuner. And if
practical, I'd replace that length of RG8X with something the size of
RG8. OTOH, doubling the number of radials, realizing that length of
on-ground radials is not critical, would probably help TX signal more
than replacing that coax, and would change the feedpoint Z a bit.
While adding horizontal length is technically a great idea, sometimes
that isn't practical. I like Jeff's suggestion of an L-network at the
feedpoint, but the design requires either a lot of cut and try, or a
sweep of the feedpoint Z with a good vector analyzer whose data can be
ported to design software like SimSmith. I'll bet that Pete has
neighbors who can do that. And if Pete can send me a suitable sweep, I'd
be happy to do a design.
73, Jim K9YC
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