Okay, here's another question on antenna configuration. I have just gone
through the pricing out of backstay insulators, and received the suggestion
that a good, less expensive alternative would be to substitute a Kevlar
backstay for the rod that I have presently, and wind a piece bare of wire
around the Kevlar, up to near the masthead as an antenna. It is
significantly less expensive, and the Kevlar has the advantage of being
stronger and lighter than the wire.

Anyone know of any disadvantages to this approach??


"john s." wrote in message
om...
Glenn Ashmore wrote in message
news:JRxob.119973$sp2.25191@lakeread04...
In the process of laying up the hull I incorporated a couple hundred sq.
ft of bronze bug screen to serve as a counterpoise. In addition two
runs of 2" copper foil run down the center of the hull to the keel area.
Capacitors between the foil and the keel bolts isolate any DC from
getting back into the counterpoise. That is probably enough but as I am
installing two aluminum tanks, I wonder how kosher it would be to tie
them into the counterpoise with more capacitors.

It would add another 14 sq ft of coupling area but would it be
introducing other problems?

Glenn, I think you are overdoing it....I just have a copper strap from
the ground of the antenna tuner to one keel bolt (external lead keel)
and when I tested the syste,after installation (in New York), I got a
55 report from a ham in NW Spain. The only time Herb (Southbound II)
did not hear me loud and clear was because my copper strrap had become
corroded/
john N2ZOA/MM

This doesn't address your antenna question specifically, but I have to say
that the idea of replacing a stainless wire backstay with rope just creeps
me out. Sure Kevlar, in the appropriate size, could be stronger and still
lighter than the wire, but its long-term durability raises some significant
questions. The lifetime of stainless steel 1x19 and rod is well understood,
as is the response to shock loading; I doubt that the same could be said for
Kevlar. Your backstay's a pretty important rigging component - I wouldn't be
inclined to screw around with it. You might also consider the long-term cost
of more frequent replacement of the Kevlar, versus the cost of the wire and
insulators for about a twenty-year lifetime expectancy of the SS wire and
insulator combination.

I'm not against Kevlar in standing rigging per se, although I'd be inclined
to use it in a "supporting role", so to speak. In fact, I'm thinking of
replacing my 7x19 SS wire running backstays on my 41' 3/4-rigged sloop with
Kevlar the next time I re-rig, not so much to save weight as to keep down
the chafing on my spreaders when the running backstays are housed at the
after shrouds. I just wouldn't use in in a single-point-of-failure
application such as the backstay.

Tom Dacon


"maxlynn" wrote in message
news:hDVob.49689$hp5.39655@fed1read04...
Okay, here's another question on antenna configuration. I have just gone
through the pricing out of backstay insulators, and received the
suggestion
that a good, less expensive alternative would be to substitute a Kevlar
backstay for the rod that I have presently, and wind a piece bare of wire
around the Kevlar, up to near the masthead as an antenna. It is
significantly less expensive, and the Kevlar has the advantage of being
stronger and lighter than the wire.

Anyone know of any disadvantages to this approach??


"john s." wrote in message
om...
Glenn Ashmore wrote in message
news:JRxob.119973$sp2.25191@lakeread04...
In the process of laying up the hull I incorporated a couple hundred
sq.
ft of bronze bug screen to serve as a counterpoise. In addition two
runs of 2" copper foil run down the center of the hull to the keel
area.
Capacitors between the foil and the keel bolts isolate any DC from
getting back into the counterpoise. That is probably enough but as I
am
installing two aluminum tanks, I wonder how kosher it would be to tie
them into the counterpoise with more capacitors.

It would add another 14 sq ft of coupling area but would it be
introducing other problems?

Glenn, I think you are overdoing it....I just have a copper strap from
the ground of the antenna tuner to one keel bolt (external lead keel)
and when I tested the syste,after installation (in New York), I got a
55 report from a ham in NW Spain. The only time Herb (Southbound II)
did not hear me loud and clear was because my copper strrap had become
corroded/
john N2ZOA/MM

Composite stays are the big thing with multihull sailors but when I
checked it out for monohulls it seems that stretch will be a problem.
High tech line seems to be strong enough but it evidently still
stretches more than stainless wire.

Tom Dacon wrote:

This doesn't address your antenna question specifically, but I have to say
that the idea of replacing a stainless wire backstay with rope just creeps
me out. Sure Kevlar, in the appropriate size, could be stronger and still
lighter than the wire, but its long-term durability raises some significant
questions. The lifetime of stainless steel 1x19 and rod is well understood,
as is the response to shock loading; I doubt that the same could be said for
Kevlar. Your backstay's a pretty important rigging component - I wouldn't be
inclined to screw around with it. You might also consider the long-term cost
of more frequent replacement of the Kevlar, versus the cost of the wire and
insulators for about a twenty-year lifetime expectancy of the SS wire and
insulator combination.

I'm not against Kevlar in standing rigging per se, although I'd be inclined
to use it in a "supporting role", so to speak. In fact, I'm thinking of
replacing my 7x19 SS wire running backstays on my 41' 3/4-rigged sloop with
Kevlar the next time I re-rig, not so much to save weight as to keep down
the chafing on my spreaders when the running backstays are housed at the
after shrouds. I just wouldn't use in in a single-point-of-failure
application such as the backstay.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

Okay, now that you have given your opinion on Kevlar as a backstay, how
about addressing the original question - i.e., is there any conceptual
problem with wrapping a bare copper wire around it and using it for an
antenna? Has anyone done this?

And, oh by the way, how would you feel about using Kevlar as a substitute
for 1x19 in steering cables? Would it shock you to know that many boats are
using Kevlar in this highly critical application? And have been doing it
successfully for over ten years now? Use as a backstay is pretty mundane
by comparison. And others have been using it for a similar period as
backstay material. And contrary to what you suggest, the lifetime and other
properties of Kevlar are well understood.


"Tom Dacon" wrote in message
...
This doesn't address your antenna question specifically, but I have to say
that the idea of replacing a stainless wire backstay with rope just creeps
me out. Sure Kevlar, in the appropriate size, could be stronger and still
lighter than the wire, but its long-term durability raises some
significant
questions. The lifetime of stainless steel 1x19 and rod is well
understood,
as is the response to shock loading; I doubt that the same could be said
for
Kevlar. Your backstay's a pretty important rigging component - I wouldn't
be
inclined to screw around with it. You might also consider the long-term
cost
of more frequent replacement of the Kevlar, versus the cost of the wire
and
insulators for about a twenty-year lifetime expectancy of the SS wire and
insulator combination.

I'm not against Kevlar in standing rigging per se, although I'd be
inclined
to use it in a "supporting role", so to speak. In fact, I'm thinking of
replacing my 7x19 SS wire running backstays on my 41' 3/4-rigged sloop
with
Kevlar the next time I re-rig, not so much to save weight as to keep down
the chafing on my spreaders when the running backstays are housed at the
after shrouds. I just wouldn't use in in a single-point-of-failure
application such as the backstay.

Tom Dacon


"maxlynn" wrote in message
news:hDVob.49689$hp5.39655@fed1read04...
Okay, here's another question on antenna configuration. I have just
gone
through the pricing out of backstay insulators, and received the
suggestion
that a good, less expensive alternative would be to substitute a Kevlar
backstay for the rod that I have presently, and wind a piece bare of
wire
around the Kevlar, up to near the masthead as an antenna. It is
significantly less expensive, and the Kevlar has the advantage of being
stronger and lighter than the wire.

Anyone know of any disadvantages to this approach??


"john s." wrote in message
om...
Glenn Ashmore wrote in message
news:JRxob.119973$sp2.25191@lakeread04...
In the process of laying up the hull I incorporated a couple hundred
sq.
ft of bronze bug screen to serve as a counterpoise. In addition two
runs of 2" copper foil run down the center of the hull to the keel
area.
Capacitors between the foil and the keel bolts isolate any DC
from
getting back into the counterpoise. That is probably enough but as
I
am
installing two aluminum tanks, I wonder how kosher it would be to
tie
them into the counterpoise with more capacitors.

It would add another 14 sq ft of coupling area but would it be
introducing other problems?

Glenn, I think you are overdoing it....I just have a copper strap from
the ground of the antenna tuner to one keel bolt (external lead keel)
and when I tested the syste,after installation (in New York), I got a
55 report from a ham in NW Spain. The only time Herb (Southbound II)
did not hear me loud and clear was because my copper strrap had become
corroded/
john N2ZOA/MM

More elegant would be to use a single braid Vectran. It would take some
patience but you could feed the wire up through the core. I still see
several potential problems.

The first is the termination. Arimids and other high tech lines like
PBO require equal tension on all fibers to maintain rated strength.
Small eye splices will cut strength considerably. Special terminations
that pot the fibers inside a hollow steel fitting are available but cost
more than an insulator and must be factory installed.

The second is stretch. No matter how high the modulus of the fiber,
braided line will creep. The Kevlar 49 stays on boats like the Volvo
Ocean 70's is parallel fiber inside a polyethylene cover. A backstay
cost as much as a pretty decent crosscut mainsail.

BTW, composite steering cables are rarely Kevlar. With the exception of
Technora, arimid fibers have a tendency to chafe against each other when
the line is routinely flexed under tension as around steering sheaves.
Vectran and Technora are the preferred fibers for that application.

maxlynn wrote:

Okay, now that you have given your opinion on Kevlar as a backstay, how
about addressing the original question - i.e., is there any conceptual
problem with wrapping a bare copper wire around it and using it for an
antenna? Has anyone done this?

And, oh by the way, how would you feel about using Kevlar as a substitute
for 1x19 in steering cables? Would it shock you to know that many boats are
using Kevlar in this highly critical application? And have been doing it
successfully for over ten years now? Use as a backstay is pretty mundane
by comparison. And others have been using it for a similar period as
backstay material. And contrary to what you suggest, the lifetime and other
properties of Kevlar are well understood.


--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"maxlynn" wrote in message
news:Ygppb.52870$hp5.43787@fed1read04...
Okay, now that you have given your opinion on Kevlar as a backstay, how
about addressing the original question - i.e., is there any conceptual
problem with wrapping a bare copper wire around it and using it for an
antenna? Has anyone done this?

The original question (Glenn's), has to do with extending the SSB foil
lattice to the fuel tanks. In response to that, the consensus of the sources
I've referenced for my SSB ground system is that running the foil to the
tops of the tanks is a good thing to do. I've done this on my tanks, and
merely laid the foil on top of the tank surface with an adhesive bonding
agent (it was probably Sikaflex). I don't believe there's any need for an
electrical bond, since induction should do the job nicely.

Tom Dacon

In article ,
"Tom Dacon" wrote:

I don't believe there's any need for an
electrical bond, since induction should do the job nicely.


The above doesn't take into account that we are dealing with
impedance in the frequency domain. By not having an good
electrial bond, you induce capacative coupling to additional
surface area for your RF Ground, That means that this coupling is
frequency sensative, and then the RF Grounding System will react
significantly different depending on the frequency being transmitted.
Autotune Antenna Couples have very specific tuning firmware, and this
code doesn't react very well to a highly variable Rg Ground impedance.
They are designed to operate against a FLAT RF Ground Impedance,
and the more bumps in the RF Gropund impedance the harder the tuner
has to work to tune the antenna, and the more phantom, and quirky
Low SWR points that the tuner will find, and lock on to.

Bruce in alaska
--
add a 2 before @

When I could not tune out the ground impedance bumps, I installed a cheap
manual antenna tuner in the ground circuit leg. Then I got perfect
impedance matches at all frequencies into a long ground wire. This was in
addition to the normal automatic antenna tuner for the antenna. Tuning
was simple. Just adjust the ground tuner until the SWR was down to the
lowest you could get.

Larry DeMers



Bruce in Alaska wrote:

In article ,
"Tom Dacon" wrote:

I don't believe there's any need for an
electrical bond, since induction should do the job nicely.

The above doesn't take into account that we are dealing with
impedance in the frequency domain. By not having an good
electrial bond, you induce capacative coupling to additional
surface area for your RF Ground, That means that this coupling is
frequency sensative, and then the RF Grounding System will react
significantly different depending on the frequency being transmitted.
Autotune Antenna Couples have very specific tuning firmware, and this
code doesn't react very well to a highly variable Rg Ground impedance.
They are designed to operate against a FLAT RF Ground Impedance,
and the more bumps in the RF Gropund impedance the harder the tuner
has to work to tune the antenna, and the more phantom, and quirky
Low SWR points that the tuner will find, and lock on to.

Bruce in alaska
--
add a 2 before @

In article , Larry Demers
wrote:

When I could not tune out the ground impedance bumps, I installed a cheap
manual antenna tuner in the ground circuit leg. Then I got perfect
impedance matches at all frequencies into a long ground wire. This was in
addition to the normal automatic antenna tuner for the antenna. Tuning
was simple. Just adjust the ground tuner until the SWR was down to the
lowest you could get.

Larry DeMers

If your going to use a manual tuner in the ground system, and have to
readjust it for every large frequency change, why would you not just put
the manual tuner on the antenna and just do manual tuning??? Kind of
redudndent isn't it. The whole point of a autotuner is so that the
operator doen't have to know or understand what the tuner is doing.
That, and so appliance operators could install their own SSB Radio's
systems and cut the Marine Electronics Tech's out of their Installation
Money. Same thing, as when the FCC changed the rules for Radar
Installations, by users, only with many more consequencies.

Bruce in alaska
--
add a 2 before @

Bare copper will corrode rather quickly. Insulated copper would be
better but the insulation will probably degrade in the UV. Bare SS
would probably be best. I have a split backstay where the split is
fairly high up. I ran a separate antenna from the masthead using
thin SS wire, small insulator at the top. Bottom had a small insulator and
a spring to absorb any mast pumping. Attached it to the radar arch. It
worked well, but not any better than the 23' fiberglass whip mounted to
the transome.

Doug

"maxlynn" wrote in message
news:Ygppb.52870$hp5.43787@fed1read04...
Okay, now that you have given your opinion on Kevlar as a backstay, how
about addressing the original question - i.e., is there any conceptual
problem with wrapping a bare copper wire around it and using it for an
antenna? Has anyone done this?

And, oh by the way, how would you feel about using Kevlar as a substitute
for 1x19 in steering cables? Would it shock you to know that many boats
are
using Kevlar in this highly critical application? And have been doing it
successfully for over ten years now? Use as a backstay is pretty mundane
by comparison. And others have been using it for a similar period as
backstay material. And contrary to what you suggest, the lifetime and
other
properties of Kevlar are well understood.


"Tom Dacon" wrote in message
...
This doesn't address your antenna question specifically, but I have to
say
that the idea of replacing a stainless wire backstay with rope just
creeps
me out. Sure Kevlar, in the appropriate size, could be stronger and
still
lighter than the wire, but its long-term durability raises some
significant
questions. The lifetime of stainless steel 1x19 and rod is well
understood,
as is the response to shock loading; I doubt that the same could be said
for
Kevlar. Your backstay's a pretty important rigging component - I wouldn'
t
be
inclined to screw around with it. You might also consider the long-term
cost
of more frequent replacement of the Kevlar, versus the cost of the wire
and
insulators for about a twenty-year lifetime expectancy of the SS wire
and
insulator combination.

I'm not against Kevlar in standing rigging per se, although I'd be
inclined
to use it in a "supporting role", so to speak. In fact, I'm thinking of
replacing my 7x19 SS wire running backstays on my 41' 3/4-rigged sloop
with
Kevlar the next time I re-rig, not so much to save weight as to keep
down
the chafing on my spreaders when the running backstays are housed at the
after shrouds. I just wouldn't use in in a single-point-of-failure
application such as the backstay.

Tom Dacon


"maxlynn" wrote in message
news:hDVob.49689$hp5.39655@fed1read04...
Okay, here's another question on antenna configuration. I have just
gone
through the pricing out of backstay insulators, and received the
suggestion
that a good, less expensive alternative would be to substitute a
Kevlar
backstay for the rod that I have presently, and wind a piece bare of
wire
around the Kevlar, up to near the masthead as an antenna. It is
significantly less expensive, and the Kevlar has the advantage of
being
stronger and lighter than the wire.

Anyone know of any disadvantages to this approach??


"john s." wrote in message
om...
Glenn Ashmore wrote in message
news:JRxob.119973$sp2.25191@lakeread04...
In the process of laying up the hull I incorporated a couple
hundred
sq.
ft of bronze bug screen to serve as a counterpoise. In addition
two
runs of 2" copper foil run down the center of the hull to the keel
area.
Capacitors between the foil and the keel bolts isolate any DC
from
getting back into the counterpoise. That is probably enough but
as
I
am
installing two aluminum tanks, I wonder how kosher it would be to
tie
them into the counterpoise with more capacitors.

It would add another 14 sq ft of coupling area but would it be
introducing other problems?

Glenn, I think you are overdoing it....I just have a copper strap
from
the ground of the antenna tuner to one keel bolt (external lead
keel)
and when I tested the syste,after installation (in New York), I got
a
55 report from a ham in NW Spain. The only time Herb (Southbound II)
did not hear me loud and clear was because my copper strrap had
become
corroded/
john N2ZOA/MM