Listed below is a querry that I recently
posted here. Also listed are 11 responses
on the topic of "to break up or not to
break up guy-wires" Many thanks to all
who responded and maybe this compilation
will assist others who are pondering this
same question. I intentionally omitted the
names/callsigns of those who responded but
left their messages intact.
I think, the way we're going to go on our
project is to "break-up" or partially
break-up the "top" set of guys on each of the
3 towers and "not" break the rest. Predictably
some recommend "Phillystrand" and I must say
that "if" we were going to have to "buy"
all the material then the augurement that
"philly" is cost effective is probably a good
one. In the circles in which I travel though
we "scrounge & barter alot" and usually come
up with the hardware for a mere fraction of
retail ie- guy wire, wrap-on clamps and
insulators. Phillystrand is not so easy to
obtain via the same means etc. Some main
points i'll list below, some of which will be
again covered in the responses.
* If not "breaking up", then insulate the guys
at the tower (2 or so ft away) so as to allow
for the "shunt feeding" of the tower.
We will do this. Also may place a "bypass
jumper" across the "johnny ball" and remove
um later if the tower is not going to be
immediately shunt fed.
* The K4VX article was in August QST
* Will attach top guys to tower at about 5 feet
down from the top.
* May try & obtain some "utility type" fiberglass
insulators "Joslyn type" to use at the tower.
* In reality, I dont think this 3 tower site
will ever be used for contesting but mainly
dxing. But u can never tell.
* May play with "top" guys on the 130' tower
& attempt to use them as 1/4 wave slopers on
160 or 1/2 vave slopers on 80. Likewise on
the 90 footers maybe have some of the top guys
as qtr wave slopers on 80.
* Below follows my orig message and the responses.
Again thanks for the replies as we did gain
lots of info plus they "triggered" some additional
thoughts too.
Ed KG4W
Friend of mine is going up with 3 towers at his
new qth soon and I would like input re this topic.
I recall an article (i think in QST by again "i think"
K4VX) on the pro's & cons of breaking up guy wires.
As I remember the article, the bottom line was
that the benefits were not worth the time and
expense. This is going to be a 3 tower site, all
guyed towers and at heights of 90, 90 & 130 ft.
The main question of course is should he or
shouldn't he break up the guys ?
If you feel he should break up the guys, then
the questions become-
A- what is the best length at which to break um ?
B- should they all be broken up ?
C- should all the broken up guys be insulated
close to the tower or insulate at a distance
from the tower equal to A above.
If you feel theres no need to break um up then
consider these
A- Should the guys be insulated from the tower
or attach stright to it ?
B- Is there any particular guy length to try to attain
or to avoid if possible
C- I would guess it would be best to have the top
attach to the tower as far down from the top as
feasable ?
Add any other comments etc that you have.
73's Ed KG4W
NNNN
RESPONSE 1
If you follow the advice in the QST article by K4VX,
you will be making a serious mistake. K4VX's particular
guy wires happened not to much influence his particular
antennas. He then erroneously generalized this experience.
I think this is the most misleading article on antenna
design to appear in QST in many years. Its conclusions
are provably false.
It's easy to demonstrate that extreme degradation of
pattern and gain can occur in certain circumstances with
unbroken guys by including both antennas and guy wires
in the same computer model. This is something you can
verify for yourself with any antenna-analysis program.
For many years I have included such an example file with
my antenna software to warn hams of the severe problems
that guy wires can cause.
If you don't analyze your particular tower geometry, you
might get lucky as K4VX did and experience little
interaction. Or, you might have bad luck as N6ND did.
Although cut to the "nonresonant" lengths recommended
in the ARRL Antenna Book, guy wires on his 100-foot tower
noticeably degraded the performance of an optimized
15-meter Yagi stack. Moreover, the guy wires on an
adjacent 20-meter tower degraded the pattern and forward
gain of the lower 15-meter Yagi when it was pointed in
their direction! A computer model of the two towers
and guy wires verified what we saw experimentally.
But the model came too late to save the many hours we had
to spend recutting the guy wires to better lengths.
Guy-wire/antenna interaction can be complex. If you're
making a serious investment of time and money, you owe
it to yourself not to leave the effects of incidental
conductors to chance.
RESPONSE 2
Yes, Lew wrote the article. What I recall is that his
claim was that, based on his computer models, there was
*only* a 1dB difference between properly broken-up guys
and not broken up ones. Let me ask you this: how many
contesters do you know that spend alot more money
for hardline, a stack, or change to monobander(s) just
to recover a dB or two? In my opinnion it is well
worth the effort. One dB loss on receive is ALOT,
especially if you have a substantial antenna system
already in place. But then again, YMMV.
RESPONSE 3
Ed - Better yet, use Phillystran. Then you don't have
to worry about breaking up guy wires. I recall reading
a cost comparison between steel and Phillystran, and
by the time you add up costs of insulators, dead
ends, etc. to break up the guys, there's not much of
a difference.
RESPONSE 4
The answer is VERY simple! Philystrand!
I have somewhere around 13 towers, ALL with Philystrand.
If you do it right, according to the Rohn manual and to
engineering specs for materials and strength, you will
find that the cost of steel guy, insulators, clamps, etc,
will cost the SAME as Philystrand.. And the cost of time
and labor to assemble the mess...Your ground crew will
quickly lose interest.
If you consider the "reliability" factor and chance
for part failure, you will quickly realise that
Philystrand is CHEAPER than broken up guys!!!
(A tower is NO PLACE to skimp on cheap parts!)
Also Philystrand is invisible to RF and you don't have to
worry at all about so-called interactions! The new
guy-grips are incredible!
Good luck!
RESPONSE 5
The last time we visited this subject, 3 camps arose:
(1) Why bother breaking up guys? If you put a monetary
value on your time, buy and install Phillystran to a height
of 12 feet above ground. If you want to save some money,
use Philly on the top two sets and go with solid steel
below.
(2) Break 'em up. If you keep your eyes open you can find
good deals on grips, insulators, clips, whatever. Why
bother valuing time? The construction is part of the hobby.
(3) Don't break 'em up. You can always do it later when
you discover which are resonant and which are not. OR,
detune them by adding a few additional feet to change the
resonant frequency.
Me? I'm a Philly guy.
RESPONSE 6
>(3) Don't break 'em up. You can always do it
later when you discover which are resonant and which
are not. OR, detune them by adding a few additional
feet to change the resonant frequency.
This may be the way to go.
At N5AU, none of the guys were broken up except on
those towers where guys were made from guy wire scraps.
I believe the high 20M tower had some philly on the
upper guys. Everything, including the stacks looking
through all kinds of guy wire seemed to work just FB.
RESPONSE 7
Hi Ed,
The N5AU station did not break up guy wires. I think
the results of that station speak for themselves.
RESPONSE 8
It was QST, and not that long ago - maybe 93. I wasn't
too impressed -- it always seemed to me to be a mistake
to generalize from one installation.
Here's the variation I tried after listening to a lot
of arguments: My 100-foot tower has 3 guys - at 32,63
and 95 ft, per Rohn. On the top set, I used 21-foot
Joslyn power pole insulators - fibreglas rods with
clevises on each end - from the tower out (you guessed it)
21 feet. My theory on that was that the first metal my
tri-bander would see would be at least 18-19 feet out
from the tower and over 25 feet down from the antenna.
The insulators only cost $50 each - pretty reasonable.
On my lower guys, I used a single insulator about 2 feet
out from the tower. The remaining lengths of my guy wires
aren't resonant on 40, 80 or 160, according to the table
in the Handbook. I was going to leave them connected to
the tower, but was convinced by W3LPL that this would
preclude slopers or shunt feeding.
The advantage of this approach is that it's a lot easier
to find non-resonant lengths if you're not worrying about
10-20 meters.
If/when I go to a stack, I'll probably put the Joslyn
insulators on my second guy set as well. Also, at some
point I want to model my setup (and maybe measure currents
in the guys as well) to see if there's any interaction on
the lower bands. My 80-meter inverted vee seems to play
very well, even though its elements run close to parallel
with the lower guys, but that could be just serendipity.
I'm planning to convert it to a delta loop and that, of
course, could be a whole different story.
>C- I would guess it would be best to have the top
> attach to the tower as far down from the top as
> feasable ?
You need to be conscious of mechanical considerations
here, but rohn recommends 5 feet down on a pointy-top
25 top section, so you can clearly do some of that.
RESPONSE 9
I've got 110' of 45G with solid guys. I've not noticed
a problem with them affecting the pattern of the beams.
The computer models agree. I would seek out Brian
Beezley , K6STI. He has (I think) a guy wire program.
I'm seriously considering breaking up the top set so
I can use them for 1/4 wave slopers on 160. Another
consideration is if there are ever going to be side mount
beams at lower levels. The wire may have a significant
affect on the pattern if it is directly in front.
>If you feel theres no need to break um up then
>consider these
>A- Should the guys be insulated from the tower
> or attach stright to it ?
Mine are directly attached. I also bonded them to the
tower leg and did the ground rod thing at the anchor.
Some have suggested that you isolate at the tower and
the anchor to keep lightning from using the guy strand
as a path to ground. Based on my utility experience,
about the only way to avoid that problem is to use
Phillystran. If the bolt traveled 2 or 3 miles to get
to your tower, a silly little 502D porcelain insulator
ain't gonna slow it down.
>B- Is there any particular guy length to try to attain
> or to avoid if possible
I don't think there is much of a problem if they are
bonded top and bottom.
>C- I would guess it would be best to have the top
> attach to the tower as far down from the top as
> feasable ?
>
My computer models don't indicate so. My ring rotor and
40M beam are just above the top set.
RESPONSE 10
I never found any interactions between unbroken guys and
beams on the top of tower. I think I vaguely remember
one case where a lower antenna on a side mount had an SWR
change as it rotated over a guy. Did not seem to hurt
anything and the change was slight. I now use about 30-50'
of Phillystran at the top of the uppermost guy set and no
breaks after that. There are several reasons for this:
as a M/M on occasion, I like to keep stray RF at
a minimum; no worry about a corroded tower/guy joint near
an antena causing harmonics or signal mixing; and I can run
low band wires right over the Phillystan if I want without
fear of arcing to a metal guy.
One interesting thing about guys - I had a pair of virtually
identical 125' towers, each with an 80 meter sloper hanging
from the top. The slopers were cut identically & spaced
equally between the guys and stretched out the same distance
horizontally. These towers were about 125' apart and the
slopers were "broadside", that is the towers were on a N-S
line and the slopers hung off to the west. Naturally, one of
the slopers was better than the other one, despite my efforts
to find out why. The difference was normally about 1/2 S unit,
but sometimes considerably more. After a long time, I realized
there was a difference in towers - although they were both
guyed every 25' (5 guy sets), one tower had guys broken with
insulators and the other did not. The tower with the unbroken
guys had the better sloper. The only thing I can figure is that
all those guys and that big tower had enough metal to act as a
reflector, almost like a compromise vertical corner reflector.
This sloper even has a couple S units front-to-back. On the
other tower, the insulated guys never had a long enough unbroken
stretch of metal to act like a relector, so it barely had any
front-to-back and a lot less gain in the favored direction.
I still use that "good" west sloper as it has outperformed every
other wire antenna I've tried, including delta loops, inverted
vees, high dipoles and vertical dipoles. I guess sometimes guy
wires can do more than just hold up a tower.
RESPONSE 11
Ed,
A few thoughts If you want to shunt feed a tower, the guys
should be insulated from the tower. You should talk to K3LR.
He had some good info/ideas about this topic. Bottom line was
that he used 50' of Phillystran connected to tower and finished
with regular EHS guywire. The guy wire will cost more but you
save a lot on guy grips/clamps and insulators by not breaking
it up.
NNNN
>From k0wa@southwind.net (Lee Buller) Fri Apr 26 02:41:21 1996
From: k0wa@southwind.net (Lee Buller) (Lee Buller)
Subject: Amps again
Message-ID: <199604260141.UAA18571@onyx.southwind.net>
Ok Gentlemen and Ladies....
I have eliminated QRO Amps and Ten TEc amps...and if someone wants to give a
great deal on an Alpha...i will listen to them. But, those are out of the
price range.
Anyone have comments on the Ameritron AL-82 or the Al-1200? I understand
blowers were noising in hte beginning, but have they gotten better in recent
production runs?
Let me know what you think from your experience.
The SB-220 could make the trip to Dayton this year...never to return!
Lee
k0wa@southwind.net
>From Frank Donovan <donovanf@sgate.com> Fri Apr 26 02:50:41 1996
From: Frank Donovan <donovanf@sgate.com> (Frank Donovan)
Subject: Silver Anniversary
Message-ID: <Pine.OSF.3.93.960425214312.17933A-100000@jekyll.sgate.com>
On Thu, 25 Apr 1996, Jim Stahl wrote:
>
> As many of us are having a strange feeling about the approaching
> final weekend of April with no trips planned, we observe a
> notable anniversary. It was 25 years ago, April 24, 1971, that
> the Mad River Radio Club was formed at a meeting at the VJ
> Pancake House in downtown Dayton.
Jim,
I'm sure you recall the details, but I wonder how many other contesters
recall the events associated with this object that has graced my desk for
the past nearly 25 years:
Its a gavel engraved as follows:
Potomac Valley Radio Club
----------------------
---------^-------
Won in the A.R.R.L. Sweepstakes 1971
73!
Frank
W3LPL
donovanf@sgate.com <---reply address
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