Richard Clark wrote:

On Sun, 18 Apr 2004 18:10:13 GMT, zeno wrote:

Hi Richard,

I think at least one of the metal masts I will be using to hang the 160m
loop might lend itself to the vertical antenna you suggest.

Hoist wire for the rest! After all, you are already doing that aren't
you?


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. 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.

Using wire guys would be easier. Aside from all this additional complication
of anticipating some kind of future vertical antenna system I barely
understand at this point, is it definitely ok to use wire as guys? I might
just use wire guys, not broken up with insulators, not worrying about these
future antenna possibilities. These masts are simply too far away from the
shack, but I need to guy them just to put them up.

When using metal masts for wire antennas, what is the standard practice for
guying these masts?






Folded Unipole (N. O. L.);
Type UG;
NORD;
Triangular Folded Unipole (VOA aboard the USCGC Courier)


"The Amateur Radio Vertical Antenna Handbook," Capt. Paul H. Lee, N6PL

2. What band, or bands, would it be good for? (Assuming the guy wires are
generally in the position of effectivenes as guy wires.)

Folded Triangular Unipole is 45 feet tall and rated from 3 to 10.5 MHz

NORD 30 feet tall and rated from 2 to 4 MHz;

Folded NOL Unipole is 0.124 wavelength tall;

Type UG is 0.048 wavelength tall.


I will not really understand this antenna until I can see a simple picture of
it somewhere, and, since I am a beginner, would need to know what purposes
such an antenna might serve me at this point, eg. is there a particular band
or a particular advantage that I cannot get elsewhere with my other more
common antenna systems. I am at a point where I am simply looking for
possible worthwhile antennas I can construct hoping that one or two might
prove effective.

You did mention something about the advantages of vertical over horizontal
and I was not sure which band you were referring to. At this point I have not
considered any vertical antennas, but am open to verticals, if not the folded
unipole you are discussing, maybe some other kind of vertical. At this point
I don't know anything about verticals really other than the hassel of putting
in radials. I like the idea of a mast being an antenna and the guy wires
being part of the antenna, but what I need is a child's picture book
illustration of such an antenna and why such an antenna would be the bees
knees for me.


Here is what I currently (and practically) understand about the antenna you
are discussing. It is a vertical folded dipole of some kind in which the 50'
mast is one leg, another drop wire from the top is the other half (which I
assume is fed somewhere in the middle of this drop wire by hooking up coax
feed line). In addition to this folded dipole (vertically oriented) and with
one leg (the mast) much greater diamter than the other half (drop wire), it
has a bunch of guy wires attached to the mast at various points which somehow
add something to the antenna, the guy wires need to be some special length.
There needs to be an elaborate radial system underneath threaded through the
orchard with weeds growing on top of them and not shallow enough to get
caught in the mower. To even use this antenna, on whatever mysterious band it
is good for, I would have to make special electronic accomodations to deal
with the loss resulting from the feedline being greater than 500 feet to the
shack (or move the shack closer to the antenna), eventually this long
feedline would have to be in conduit and buried.

I think that it would be easier just to put up another mast, closer to the
shack, just for the purpose of exploring this antenna, rather than bend over
backwards to make use of a mast out in the field just because it is there.
These old telescoping tv masts are plentiful at the county dump, I will keep
collecting them. It is conceivable I could put one up with a feedline less
than 200 feet to the shack, that shouldn't be any problem with loss, no?

But I still need to know, or be reminded, in the simplest of terms, why I
want such an antenna, and what special advantages it might have on what bands
I might eventually be excited about.

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

zeno wrote:
This goes back to my original question, should I use rope or wire for the
guys on these masts?

Not only do I use non-conductive rope/string for my guy "wires",
I use non-conductive supports, wood/fiberglas. Works for me.
--
73, Cecil http://www.qsl.net/w5dxp




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