Guy wire vs. guy rope
 

I am getting ready to put up my masts (5 of them) for a 160m
full wave loop. For the most part I am using recycled
telescoping tv masts which will be up around 50+ feet. The
masts are metal. There will be a pulley at the top of the
mast and the antenna will be pulled up with a dacron rope.

The question is what material to use for the guy wires on the
masts. Is there a compelling argument not to use wire guys
because they might be of lengths that will resonate or
otherwise detract from the anticipated effectiveness of this
antenna, or is this a non issue, given that the mast is
already metal anyway, and the rope to the insulator holding
up the antenna wire (#14 hard drawn braided copper) will be
approximately 10 feet away from the top of the mast.

Wire for the guys (three sets of four wires, eg. one set for
each of the top three tiers) would be easier, and somewhat
more permanent than rope. If I were to use the dacron rope
for the guys, then I would put up pulleys (that is 12 pulleys
just on one mast) so that a new rope could be threaded up
there in the future without the mast coming down.

For all practical purposes wire guys would be permanent. If
wire is used is it necessary to break up the lengths of the
guys with dielectric strain insulators or is this a non-issue
with this antenna design.

The physical loop circumscribed by the actual circumstances
of mast placement is approx. 588 feet. The loop needs to be
about 540 feet, this difference of 48' will be absorbed by
the 5 dacron ropes pulling up the antenna, that is why I am
saying the antenna wire will be about 10' away from the tops
of the masts. It is anticipated that the antenna will be fed
by diy ladder line from one of the corners.

Any pointers or useful information is welcome.

tnx,

-bill

On Sat, 17 Apr 2004 18:14:58 GMT, zeno wrote:
I am getting ready to put up my masts (5 of them) for a 160m
full wave loop. For the most part I am using recycled
telescoping tv masts which will be up around 50+ feet.

Hi Bill,

You are on the threshold of being able to do much more for slightly
more effort.

Let's suppose you use wire with insulators to break them up (generally
only advised as a must below tower mounted beams so that opportunistic
resonances don't mess up directionality and tune).

Further, let's suppose all wires at the top have a good metal
connection to the mast.

Further, let's suppose each of these wires is broken such that the
first insulator(s) is more than 25 or 30 feet above ground (straight
down, I am not measuring along the wire).

Nothing else matters beyond what you would then do for general
construction.

I presume that all masts are driven into the ground (or at least are
not insulated from ground); and that at each mast you could build a
radial ground screen of eight to a dozen wires as broad as those first
set of insulators are out from the mast (probably 20 to 30 feet each).

You then have the opportunity of developing four broadband vertical
antennas (each with a gamma feed because of the grounded situation).
There's a good chance they would operate on 80M without too much
effort (you might push them to 160).

Most of the work is in the top connection, and the first set of
insulators - beyond that no commitments are needed if you simply
decide to walk away later. That is easy with little difference in the
up front effort.

73's
Richard Clark, KB7QHC

Richard,

Interesting, even if a bit above my current point in the learning curve.


Generally, I am experimenting with antennas here, trying to find the
junction between theoreticl concepts, and the physical realities of the
real estate, building, and trees, etc. just all hams do, I am sure.

Antenna #1 is now up, it is an OCF stung between to trees, not bad.

But now I am moving on to #2 which is this proposed 160m full wave loop.
I have collected a handful of these old masts (junk yards, the local dump
etc.) nice material to have on hand.

Here is more detail of the proposed loop, so that I can better glean
something constructive from your intriguing ideas.

Only one of the proposed masts will be resting on the ground out in the
middle of the orchard. Three are attached to buildings (adding height)
and one is attached to a sturdy wooden "telephone" pole (again adding
height and a way of mounting). The idea of putting radials in the ground
does not seem practical for most of these masts, however, your idea is
intriguing none the less.

Since I have a bunch of masts to play with, and I am in the antenna
experimental mode, and have rural real estate to play around in, I am
wondering about the antenna you have suggested.

Maybe we are talking about the possibility of Antenna #3 here.

Am I to understand that a promising antenna (you call a broadband
vertical) can be made from a single 50 foot telescoping tv metal mast,
the base of which is at ground level, utililizing the guy wires as part
of the antenna system, with a system of radials in the ground underneath?
How would I best feed this antenna, and would it be worthwhile with just
this single mast, and what advantages would such an antenna have over
others that I might construct?

At this point, I have only made plans for various wire antennas. Do not
have any verticals. The tower and beam are only a twinkle in my minds
eye, and I have to visit that neighbor who has a 75 footer he is not
using that he suggested might be for sale, but that is down the line a
way. Meanwhile I am tree fishing here, and recycling masts when I can
find them.

I have more or less concluded, that my nicest 50 foot telescoping tv
mast, is not the way to go for a "beam" and rotator, even the small ones,
the engineering of such a project seems to court a Laurel and Hardy kind
of fiasco in my imagination, at least until someone tells me that they
did it and it was smooth sailing.....

which is to say, I do not yet have a plan for some kind of antenna which
can be rotated....whatever its desing might be.....

man, there is so much to this antenna thing......it is what this is all
about.....and I love it....



-bill


Richard Clark wrote:

On Sat, 17 Apr 2004 18:14:58 GMT, zeno wrote:
I am getting ready to put up my masts (5 of them) for a 160m
full wave loop. For the most part I am using recycled
telescoping tv masts which will be up around 50+ feet.

Hi Bill,

You are on the threshold of being able to do much more for slightly
more effort.

Let's suppose you use wire with insulators to break them up (generally
only advised as a must below tower mounted beams so that opportunistic
resonances don't mess up directionality and tune).

Further, let's suppose all wires at the top have a good metal
connection to the mast.

Further, let's suppose each of these wires is broken such that the
first insulator(s) is more than 25 or 30 feet above ground (straight
down, I am not measuring along the wire).

Nothing else matters beyond what you would then do for general
construction.

I presume that all masts are driven into the ground (or at least are
not insulated from ground); and that at each mast you could build a
radial ground screen of eight to a dozen wires as broad as those first
set of insulators are out from the mast (probably 20 to 30 feet each).

You then have the opportunity of developing four broadband vertical
antennas (each with a gamma feed because of the grounded situation).
There's a good chance they would operate on 80M without too much
effort (you might push them to 160).

Most of the work is in the top connection, and the first set of
insulators - beyond that no commitments are needed if you simply
decide to walk away later. That is easy with little difference in the
up front effort.

73's
Richard Clark, KB7QHC

On Sat, 17 Apr 2004 19:16:52 GMT, zeno wrote:
Am I to understand that a promising antenna (you call a broadband
vertical) can be made from a single 50 foot telescoping tv metal mast,
the base of which is at ground level, utililizing the guy wires as part
of the antenna system, with a system of radials in the ground underneath?
How would I best feed this antenna, and would it be worthwhile with just
this single mast, and what advantages would such an antenna have over
others that I might construct?

Hi Bill,

We will do this by stages.

We are going to maximize what you already have: mast material.

Grounded or ungrounded are immaterial - there are ways of getting RF
into either. If grounded, this may require a drop wire described
below (I was a little too enthusiastic about possibilities in the
first post).

The masts will be guyed. The trick here is to think in advance to be
able to support ANY mission, vertical OR horizontal antennas. BOTH
may be available at the same time.

The usual vertical of 50 feet may resonate at several places in HF,
but almost certainly not in the Ham bands - so we must expect some
form of matching along the way. For ungrounded masts this can be done
within a meter of ground so there is no going aloft to perform any
jobs. For grounded masts you may wish to have a conductive yard arm,
perhaps more accurately described not as a yard but as 18 inches,
dropping a wire to ground for a 160M or 80M Gamma feed, or as a folded
monopole.

Note, I suggest 160M or 80M operation for an obviously too short
vertical. This is where the guy wires come in handy. As described
previously, think of them as the skeleton of an umbrella (no fabric,
but ribs expanded out). With the use of insulators, this can be
achieved so that you can construct what is called a "capacitive top
hat." Such additions to verticals lower their resonance (but this
does not imply it makes them 50Ohms - that is a separate issue). You
want them to be resonant (so they will absorb and radiate power), but
you will need to match them further (no different that any wire
antenna for that matter). For 80M, this antenna will probably offer
20 to 30 Ohms (not bad, but not 50). For 160M, this antenna could
offer 5 to 20 Ohms (becoming difficult, but not undo-able), but in all
likelihood, it will also have reactance (the top hat will probably not
be big enough).

Now, why would you want another 160M antenna? The bad news is that
horizontals in this band are abysmal performers even if you could get
one up the minimum quarter wave (a long way from only 50 feet up).
Verticals on the other hand use earth far more effectively for
communication in this band (how many AM stations do you know of with
horizontal antennas?). 80M sits on the borderline of earth
characteristics where horizontals may do better, but this doesn't mean
that verticals do poorer. Higher bands see earth differently, and
verticals need height (lifted into the air) to compete; or they need
to reside near a lake or the sea.

However, most of this discussion gets very far afield. The point is
to plan ahead, construct top hats (they will mix easily with your loop
project) and think about the gamma drop wires if the masts are
grounded. This is very little investment and you have four
opportunities (this then brings experimentation with phased, vertical
arrays - each mast driven separately through delay lines).

73's
Richard Clark, KB7QHC

Richard,

tnx a bunch for this fb. I am going to digest it a bit while I go out and mow
the weeds around the prospective antenna mast sites (in my usual effort to
convert manual labor into my preferred fantasies). I do see your important
point about anticipating future possibilites before these beasts are already
committed in the air, I like that approach. You have also inspired me to
re-examine some of those carelessly glossed over chapters in the various
Antenna books here at the shack.

We will undoubtedly need to continue this qso a bit more for me to fully
apply your ideas to the particularities here.

So, to understand something basic: What you are talking about is not
necessarily interferring in any way with the 160m loop project, but rather
to anticipate additional antenna experiments utilizing the poles (masts). If
the vertical antenna ideas are later explored, would each mast be a separate
antenna requiring its own coax feed line?

btw, my newbie's facination with the ladder line fed 160 loop has to do with
its multi-band promise. To tell the truth, I have heard very little on 160m
here. Seems like (at least with the new 80m OCF (up 30' ++ depending on which
end) I am hearing alot on 20, 40, and 80 with this old Knwd 530. Sure beats
the old tube Hallicrafters I was using only a few months ago when I started
my process of catching up with 50 years inactivity....!

I might end up one of those hams that loves the old tube gear, but also uses
the latest technology as well.....those fancy Icoms are kind of
tempting....but what do I know....

bill

Richard Clark wrote:

On Sat, 17 Apr 2004 19:16:52 GMT, zeno wrote:
Am I to understand that a promising antenna (you call a broadband
vertical) can be made from a single 50 foot telescoping tv metal mast,
the base of which is at ground level, utililizing the guy wires as part
of the antenna system, with a system of radials in the ground underneath?
How would I best feed this antenna, and would it be worthwhile with just
this single mast, and what advantages would such an antenna have over
others that I might construct?

Hi Bill,

We will do this by stages.

We are going to maximize what you already have: mast material.

Grounded or ungrounded are immaterial - there are ways of getting RF
into either. If grounded, this may require a drop wire described
below (I was a little too enthusiastic about possibilities in the
first post).

The masts will be guyed. The trick here is to think in advance to be
able to support ANY mission, vertical OR horizontal antennas. BOTH
may be available at the same time.

The usual vertical of 50 feet may resonate at several places in HF,
but almost certainly not in the Ham bands - so we must expect some
form of matching along the way. For ungrounded masts this can be done
within a meter of ground so there is no going aloft to perform any
jobs. For grounded masts you may wish to have a conductive yard arm,
perhaps more accurately described not as a yard but as 18 inches,
dropping a wire to ground for a 160M or 80M Gamma feed, or as a folded
monopole.

Note, I suggest 160M or 80M operation for an obviously too short
vertical. This is where the guy wires come in handy. As described
previously, think of them as the skeleton of an umbrella (no fabric,
but ribs expanded out). With the use of insulators, this can be
achieved so that you can construct what is called a "capacitive top
hat." Such additions to verticals lower their resonance (but this
does not imply it makes them 50Ohms - that is a separate issue). You
want them to be resonant (so they will absorb and radiate power), but
you will need to match them further (no different that any wire
antenna for that matter). For 80M, this antenna will probably offer
20 to 30 Ohms (not bad, but not 50). For 160M, this antenna could
offer 5 to 20 Ohms (becoming difficult, but not undo-able), but in all
likelihood, it will also have reactance (the top hat will probably not
be big enough).

Now, why would you want another 160M antenna? The bad news is that
horizontals in this band are abysmal performers even if you could get
one up the minimum quarter wave (a long way from only 50 feet up).
Verticals on the other hand use earth far more effectively for
communication in this band (how many AM stations do you know of with
horizontal antennas?). 80M sits on the borderline of earth
characteristics where horizontals may do better, but this doesn't mean
that verticals do poorer. Higher bands see earth differently, and
verticals need height (lifted into the air) to compete; or they need
to reside near a lake or the sea.

However, most of this discussion gets very far afield. The point is
to plan ahead, construct top hats (they will mix easily with your loop
project) and think about the gamma drop wires if the masts are
grounded. This is very little investment and you have four
opportunities (this then brings experimentation with phased, vertical
arrays - each mast driven separately through delay lines).

73's
Richard Clark, KB7QHC

On Sat, 17 Apr 2004 20:46:06 GMT, zeno wrote:

We will undoubtedly need to continue this qso a bit more for me to fully
apply your ideas to the particularities here.

Hi Bill,

That's the whole point of this group.

So, to understand something basic: What you are talking about is not
necessarily interferring in any way with the 160m loop project, but rather
to anticipate additional antenna experiments utilizing the poles (masts).

Exactimundo.

If the vertical antenna ideas are later explored, would each mast be a separate
antenna requiring its own coax feed line?

Yup - any, all, or none depending upon where the future leads.

73's
Richard Clark, KB7QHC

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. It is the one
that is a full 50' in height, and will be out in the middle of the
orchard where ground radials can be installed easily. Unfortunately this
particular mast is the one farthest away from the shack, approx. 500
feet.

Questions:

1. For reference purposes, what is the exact description (name) of this
vertical? Any recommendations for information in print about this
concept?

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

3. Would it be monoband, tuned to an exact f, or possibly multiband?

4. Where would one attach the feed line and would a run of 500' to the
shack still be worth the effort?

5. If I understand, the antenna is comprised of the mast itself (with
telescoping sections securely and electrically bonded to each other) plus
the "extension" of calculated lengths of the four guy wires, utilizing
insulators at precise points before being attached to ground anchors.

6. How would the mast be mounted to the ground? Should it ideally be
isolated from ground or contiguous with the ground? Theortically I could
build a short wooden platform or something.

7. Other than the mast itself, the four guy wires, and some kind of
system of radials in the ground, are there any other elements to this
antenna that I should know about or be thinking about?

Bill

Richard Clark wrote:

On Sat, 17 Apr 2004 18:14:58 GMT, zeno wrote:
I am getting ready to put up my masts (5 of them) for a 160m
full wave loop. For the most part I am using recycled
telescoping tv masts which will be up around 50+ feet.

Hi Bill,

You are on the threshold of being able to do much more for slightly
more effort.

Let's suppose you use wire with insulators to break them up (generally
only advised as a must below tower mounted beams so that opportunistic
resonances don't mess up directionality and tune).

Further, let's suppose all wires at the top have a good metal
connection to the mast.

Further, let's suppose each of these wires is broken such that the
first insulator(s) is more than 25 or 30 feet above ground (straight
down, I am not measuring along the wire).

Nothing else matters beyond what you would then do for general
construction.

I presume that all masts are driven into the ground (or at least are
not insulated from ground); and that at each mast you could build a
radial ground screen of eight to a dozen wires as broad as those first
set of insulators are out from the mast (probably 20 to 30 feet each).

You then have the opportunity of developing four broadband vertical
antennas (each with a gamma feed because of the grounded situation).
There's a good chance they would operate on 80M without too much
effort (you might push them to 160).

Most of the work is in the top connection, and the first set of
insulators - beyond that no commitments are needed if you simply
decide to walk away later. That is easy with little difference in the
up front effort.

73's
Richard Clark, KB7QHC

Richard,

I just remembered, there will be three tiers of guy wires (four wires at
each level), one set at the top, one set ten feet down from that, another
ten feet down from that,etc.. Can all of these guy wires be part of the
antenna system? Like you mentioned, kind of a "umbrella skeleton". It might
be tricky to make sure that the guy wires both bond to the circular ring
around the mast which the wires attach to, and to make sure that this metal
ring also bonds well to the mast, I will have to think about a good
technique here. I guess I could carefully weld them in place (normally they
are tightly fitted to the pole, but can still slide up or down), I am sure
you have seen these old tv telescoping masts, they seem fairly standard.

Bill

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. It is the one
that is a full 50' in height, and will be out in the middle of the
orchard where ground radials can be installed easily. Unfortunately this
particular mast is the one farthest away from the shack, approx. 500
feet.

Questions:

1. For reference purposes, what is the exact description (name) of this
vertical? Any recommendations for information in print about this
concept?

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

3. Would it be monoband, tuned to an exact f, or possibly multiband?

4. Where would one attach the feed line and would a run of 500' to the
shack still be worth the effort?

5. If I understand, the antenna is comprised of the mast itself (with
telescoping sections securely and electrically bonded to each other) plus
the "extension" of calculated lengths of the four guy wires, utilizing
insulators at precise points before being attached to ground anchors.

6. How would the mast be mounted to the ground? Should it ideally be
isolated from ground or contiguous with the ground? Theortically I could
build a short wooden platform or something.

7. Other than the mast itself, the four guy wires, and some kind of
system of radials in the ground, are there any other elements to this
antenna that I should know about or be thinking about?

Bill

Richard Clark wrote:

On Sat, 17 Apr 2004 18:14:58 GMT, zeno wrote:
I am getting ready to put up my masts (5 of them) for a 160m
full wave loop. For the most part I am using recycled
telescoping tv masts which will be up around 50+ feet.

Hi Bill,

You are on the threshold of being able to do much more for slightly
more effort.

Let's suppose you use wire with insulators to break them up (generally
only advised as a must below tower mounted beams so that opportunistic
resonances don't mess up directionality and tune).

Further, let's suppose all wires at the top have a good metal
connection to the mast.

Further, let's suppose each of these wires is broken such that the
first insulator(s) is more than 25 or 30 feet above ground (straight
down, I am not measuring along the wire).

Nothing else matters beyond what you would then do for general
construction.

I presume that all masts are driven into the ground (or at least are
not insulated from ground); and that at each mast you could build a
radial ground screen of eight to a dozen wires as broad as those first
set of insulators are out from the mast (probably 20 to 30 feet each).

You then have the opportunity of developing four broadband vertical
antennas (each with a gamma feed because of the grounded situation).
There's a good chance they would operate on 80M without too much
effort (you might push them to 160).

Most of the work is in the top connection, and the first set of
insulators - beyond that no commitments are needed if you simply
decide to walk away later. That is easy with little difference in the
up front effort.

73's
Richard Clark, KB7QHC

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?

It is the one
that is a full 50' in height, and will be out in the middle of the
orchard where ground radials can be installed easily. Unfortunately this
particular mast is the one farthest away from the shack, approx. 500
feet.

Questions:

1. For reference purposes, what is the exact description (name) of this
vertical? Any recommendations for information in print about this
concept?

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.


3. Would it be monoband, tuned to an exact f, or possibly multiband?

Depends on antenna type and number of guy wires. The devil is in the
details as the saying goes.

4. Where would one attach the feed line and would a run of 500' to the
shack still be worth the effort?

At the base. Run an exciter to a remote amp. That is, put your loss
into the cheapest signal to boost. Move the shack ;-)

5. If I understand, the antenna is comprised of the mast itself (with
telescoping sections securely and electrically bonded to each other) plus
the "extension" of calculated lengths of the four guy wires, utilizing
insulators at precise points before being attached to ground anchors.

Exactimundo.

6. How would the mast be mounted to the ground? Should it ideally be
isolated from ground or contiguous with the ground? Theortically I could
build a short wooden platform or something.

Folded Unipoles (which are wide band within the band of interest and
some bands are very wide) are fed with their base at ground potential
(add radials here). The feed point is through a cap, up the drop
wire. that is descending from the conductive (half) yard arm.

The other types are fed in series (the base insulated from ground).
Comparisons should be studied. If building an insulated base is no
problem, shorting it to ground becomes an easy option.

7. Other than the mast itself, the four guy wires, and some kind of
system of radials in the ground, are there any other elements to this
antenna that I should know about or be thinking about?

Don't forget the drop wire. Search the web for Folded Unipoles
(verticals) for illustrations to make this clearer. There is also a
series cap to tune it. It is basically a very big gamma match.

By varying the diameter of the drop wire to the mast diameter, you get
transformer action that boosts or lowers the feedpoint R. As most of
these are very short antennas with very low radiation resistance, the
wire diameter to mast diameter ratio often boosts that value to 50
Ohms without too much problem.

WARNING, this boost does not raise efficiency! That remains a
function of the radiation resistance compared to structure Ohmic loss
and ground loss. The feed point R is simply a boosting of BOTH the
radiation resistance AND those loss Rs too.

73's
Richard Clark, KB7QHC

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 18:19:46 GMT, zeno wrote:
I am sure
you have seen these old tv telescoping masts, they seem fairly standard.

Hi Bill,

I have a 40 foot military vertical mast that can be guyed at 4
intervals. Comes with stakes, rope (nylon), hardware, and a 5 pound
sledge hammer and it all fits into a 5 foot duffel bag.

As for bonding the lower guys (if they were wire), that would not be
par for the course. The top loading is only described at the top.
This is not to say such "linear loading" wouldn't be useful, but the
topic becomes more elaborate.

73's
Richard Clark, KB7QHC

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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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

Hi Cecil,

Tell me more about your wood/fiberglass supports. How do you make a 40-50'
mast out of this material? Is this a type of nautical craftsmanship? Do you
feel that the metal masts are inviting potential problems or do you think my
proposed loop might be in the ballpark of ok to good with the metal masts at
the corners? The actual loop wire may be ten feet away (via ropes) from the
top of the masts.

73

Bill

Cecil Moore wrote:

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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Hi Cecil,

tnx for the link. I will visit your website and get some more ideas.

73, bill

Cecil Moore wrote:

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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zeno wrote:
Tell me more about your wood/fiberglass supports. How do you make a 40-50'
mast out of this material?

I use 2x4s to get to 30' and then 1.5" fiberglass tubing for the other 20'.
If cost is no object, the entire support could be fiberglass. I got mine
from: http://www.ryanherco.com in Houston. Fiberglass pipe is really
handy for a number of applications (including Escrima Sticks :-)
--
73, Cecil http://www.qsl.net/w5dxp



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On Mon, 19 Apr 2004 00:35:21 GMT, zeno wrote:
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.

Goferit.

The answer to proximity (seeing you have more perimeter than you need)
is to simply keep the corner off, away from the mast about 10 or 20
feet. In other words, you put the masts at corners that are well
outside the bends of the loop. Thus you are suspending the loop bends
with dacron line (through the pulley) such that THOSE bends are well
inside the box described by the mast co-ordinates. (Think box inside
a box co-ordinate system. The exterior box corners, the masts,
support the interior box corners, the antenna.)
View with fixed font:

M---------------------M
|\ /|
| \ / |
| ................. |
| . . |
| . . |
| . . |
| . . |
| . . |
| . . |
| ................. |
| / \ |
|/ \|
M---------------------M

where
M is mast
--- is a ghost line
/ or \ is dacron going to antenna wire
... is antenna wire

You have the flexibility to put acreage to work for you, don't try
passing the bends through AT the mast itself.

73's
Richard Clark, KB7QHC

Hi Richard and the group,

Excellent. I can even move the 5th mast out to add even more perimeter. The
clearance at each mast will be at least 10'-15' maybe more. Your keyboard image
making was appreciated.

Did I mention that the ladder-line will be perpendicular, but moving away from the
loop more horizontally than as a strict vertical drop. The ladder-line will be
10-20' away from the mast at that corner and needs to span maybe 45+' to the house
and then maybe another 15+' feet to the matchbox. I only mention this in case I am
overlooking any precautions I may have not already considered.

It looks like the loop will have to have a bit of tension in order not to droop,
especially with these dacron extensions at each mast. I was planning to have the
loop wire free-flowing at each corner glass strain insulator (glass can handle the
abrasion, plastic could not), except the one corner closest to the point where the
ladder line-attaches in order to minimize movement at that feed point juncture.

Most of the mast materials are set to go. I still need to decide on the details of
the ladder-line construction, which wire and which spacers. I will use solid copper
wire because braided is too wiggly and might swarm at me. Insulated vs. bare? Bare
has a certain appeal. #14 vs. #12 vs. #10 (?).
Why not #10?, it is only in the air for 45'....ok maybe that is a bit heavy, a bit
overkill, maybe #12 then.... anyone ever use #10 for ladder line?


I am thinking that bare #10 (or even #12) solid copper would hold its shape
especially negotiating the curve from the 4' of PVC pipe it will be tied to above
the house at the edge of the roof peak, then arching down and crossing between some
telephone and cable tv lines, into the the side of the house through some porcelin
insulators, suspended briefly in the attic, and then down through the ceiling, again
through porcelin tube insulators. In other words, after I poke the two wires through
the side of the house into the attic, I will, shortly thereafter, be up in the attic
continuing to attach a number of spacers to these wires (wearing a dust mask and a
cob-web proof hat), until I get to that point in the ceiling where the wires will
again go through the porcelin insulator tubes, then on the other side of the ceiling
(in the "shack"), as the wire comes into the station, I will again be adding a few
more spacers until it arrives at the matchbox, at which point, I will have a coffee
break.

This way the ladder line will have no breaks from the antenna feed point to the
matchbox.

hmmmmm....what if I need to add length to my ladder-line later for some reason? I
will hate to cut into it!


Does 60-65' of ladder line seem like a "good" number. I will double check this
meaurement tomorrow. If anything, it might be longer. Are there any particular
lengths in this type of feed system I should be avoiding? BTW, the matchbox has no
160m. Until I acquire some other balanced tuner that does, if I want to try this
loop on 160m, I will have to connect it to a little balanced tuner I have here using
a balun.

I have learned that a good technique for tying the ladder line to the anchor above
the roof's edge is to weave some of that small dia. dacron line into each side of
the ladder line and use that to pull the ladder line to the support. Anyone second
this, or have another solution? Pulling on the spacers doesn't seem like a good
idea.

If I have stated anything that needs advice or correction, anyone, please don't
hesitate.

73

Bill



Richard Clark wrote:

On Mon, 19 Apr 2004 00:35:21 GMT, zeno wrote:
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.

Goferit.

The answer to proximity (seeing you have more perimeter than you need)
is to simply keep the corner off, away from the mast about 10 or 20
feet. In other words, you put the masts at corners that are well
outside the bends of the loop. Thus you are suspending the loop bends
with dacron line (through the pulley) such that THOSE bends are well
inside the box described by the mast co-ordinates. (Think box inside
a box co-ordinate system. The exterior box corners, the masts,
support the interior box corners, the antenna.)
View with fixed font:

M---------------------M
|\ /|
| \ / |
| ................. |
| . . |
| . . |
| . . |
| . . |
| . . |
| . . |
| ................. |
| / \ |
|/ \|
M---------------------M

where
M is mast
--- is a ghost line
/ or \ is dacron going to antenna wire
... is antenna wire

You have the flexibility to put acreage to work for you, don't try
passing the bends through AT the mast itself.

73's
Richard Clark, KB7QHC