Oh boy..here we go...laughing.... see below....

On Sun, 13 Jun 2004 01:05:51 GMT, Bruce in Alaska wrote:

In article ,
"Steve (another one)" wrote:

Dear all

May I pick-up on something mentioned in response to my earlier question.

It was suggested that running a wire up a kevlar backstay is a simple
soultion and avoids having to insulate a piece of conventional rigging.
This sounds very sensible to me and plan to try it, it avoids having to
mess with exposed connections to a wire backstay.

However then Bruce in alaska said:
Then just helical wrap the antenna wire
around the Kevlar Backstay and have a really nice "Fully Loaded Antenna
with alot of electrical length......

Could someone (Bruce perhaps?) explain this. Would I gain performance by
simply wrapping the wire ? Is no of turns per length of backstay
critical ? Is 'core' diameter critical ?

Thanks

Steve


Gary has a valid point in that a tightly wound helical wire will tend
to trap out the higher frequencies in the HF range. One thing to
remeber however, is that if the band is open it doesn't take as efficent
of antenna to communicate on these Higher Frequencies, and if the band
is closed, no amount of antenna tuning or fooling around is going to
allow communications. Where as on MF Frequencies, one needs all the
length one can get for an efficent antenna, and the band is what it is,
and really doesn't change much as far as open or closed, except for Day
and Night. Better distances at night than during the day. A good
compromise would seem to be a resonate 1/4 Wave at say 3200 Khz would
allow for far efficency at 2182 Khz, by wrapping the helical windings
tighter at the top of the antenna, give a reasonable length of wire
on the lower part to resonate with the tuner at 12 Mhz, 16 Mhz, and 22
Mhz.

Bruce in alaska

Bruce has an excellent point re the windings...but I see a problem.
Given a kelvar backstay length, how would one compute the
pitch of the wrap? A turn every 6 inches for the first 2/3rds? Then
every 2-3 inches for the remainder? Ouiji board?

This topic is so interesting to me that short of buying a network analyzer,
(I'll be honest, I can't afford one), I'm determined to figure out what
simple test equipment I can use to evaluate various configurations,
and then test them.
Any ideas?
Norm B