Richard Clark wrote:

On Sun, 18 Apr 2004 22:34:39 GMT, zeno wrote:

This goes back to my original question, should I use rope or wire for the
guys on these masts. If I use the dacron rope I would use pulleys so i can
later change out the rope if need be without taking down the masts.

Hi Bill,

Still a very good question. As I put pulleys up many trees (pulleys
at the bottom to for a continuous loop, flag pole style), your point
is well taken.

My
concern with using wire as guys (as was usually done with old tv masts on
roofs) was that all these lengths of wire in the proximity might in some way
adversely effect my 160m loop.

For a loop, it depends on how you drive it and if it is square. This
is the story of the origin of the quad in Quito Ecuador at HCJB. If
you corner feed it, then each corner exhibits hi-tension and becomes a
source for corona. If you center feed it, you rotate those hi-tension
points into the centers of the other sides. Less sharp bend, less
corona prospects.

I would imagine wire supports in the vicinity of a corona bend would
spell trouble.

73's
Richard Clark, KB7QHC

Hi Richard,

Interesting about the loop configurtion. My propose loop was at first going to
be square, then after scouting the actual route around the real estate here, it
became more of a trapazoid with the feed (diy ladder line) in the corner of the
shortest side. Upon more precise measurement of the actual perimeter inscribed
by the four masts, it was discovered that said perimeter was actuall about 50'
in excess of 540' loop length. Now I am planning to add the 5th mast (the one
in the middle of the orchard discussed earlier) which will both put a little new
"corner" in the longest side and also add renewed elevation (50') to an
otherwise sagging 180' continuous run, this 5th mast will be used to pull out
(via pulleys and dacron line) some of that 50' excess to the 540' loop length.

So basically we are talking a squarish 160m full wave loop, fed at a corner.
Since I may not actually hitch-hike the vertical unipole we discussed on any of
these masts (having plenty of other options on my 7 acre spread as well as other
masts) maybe I will just make life simple and use the dacron and pulleys for the
system of guys. But this does still leave the metal mast in the proximity of
these corners, so the question is: how much more of a problem (corona etc.) is
adding metal wire guys to an already existing metal mast. My simplistic
intuition is, the more wire at more angles in the vacinity cannot help the
situation. So unless I hear otherwise, I guess I will plan to use the dacron for
the guys on all masts.


Speaking of trees and pulleys. I just had my first experience putting up an 80m
OCF between two trees 140' apart. I used a sling shot method. When the antenna
was hoisted, the rope perch at the top dropped down and although the antenna
does work (especially better than my previous random end fed long wire), I do
have to do it over again to get it as high as the trees are capable of. After a
little wind storm, it dropped down further. Trees are a challenge. I am hoping
to meet the local ham-archer who, rumor has it, can shoot an arrow exactly where
you want it with exactly the right amount of momentum. He will definitely be
necessary to get a line 175' up my Eucalytus tree in the back section of the
property where I was fantasizing a 160 OCF and an alternate "getaway" shack.

I may just end up with little alternate ham shacks anywhere where I can put up a
good antenna here. This will be another definition of "mobile" or
"portable"......

Bill