SSB Antenna
 

They say there is no such thing as a stupid question, but I'm going to put
that theory to a real test.
I have removed a shroud from my catamaran to install insulators so it can be
used as the SSB antenna. Since there is no backstay as such, a main shroud
will have to do. However, I now find that the sparmaker who rigged the boat
is somewhat leery of my installing two more potential failure points in a so
highly loaded and critical support (of course, all are critical). He
suggests using one of the lowers, but these just won't be very long.
In the end I expect I'll continue with the original plan to insulate a main
shroud, but a thought came to me. The shrouds are inside a thick walled
plastic tube (which I had planned on removing), so I've wondered if rather
than using insulators I retain the plastic tube and secure a wire...or 2 or
3... along the length of the plastic tube as the antenna? I suppose the
presence of the grounded wire inside would interfere with the signal, maybe
not. Would it work?

SSB Antenna
 

"Garland Gray II" wrote in message
news:FuM9c.17580$Ft.5252@lakeread02...
They say there is no such thing as a stupid question, but I'm going to put
that theory to a real test.
I have removed a shroud from my catamaran to install insulators so it can
be
used as the SSB antenna. Since there is no backstay as such, a main shroud
will have to do. However, I now find that the sparmaker who rigged the
boat
is somewhat leery of my installing two more potential failure points in a
so
highly loaded and critical support (of course, all are critical). He
suggests using one of the lowers, but these just won't be very long.
In the end I expect I'll continue with the original plan to insulate a
main
shroud, but a thought came to me. The shrouds are inside a thick walled
plastic tube (which I had planned on removing), so I've wondered if rather
than using insulators I retain the plastic tube and secure a wire...or 2
or
3... along the length of the plastic tube as the antenna? I suppose the
presence of the grounded wire inside would interfere with the signal,
maybe
not. Would it work?

Garland,

Without having to hunt high and low for imaginary insulators that would
exceed the design strength of main strouds, consider adding a backstay _as
an antenna_ that splits off at a convenient height to connect to both stern
points Unless your boom is so long that you could not clear it with any kind
of backstay,. they could even attach to stern stanchions, as there would
never be a strain on the tie points. That would gain you a little more
clearance from the boom and walking into the antenna, etc. Running alongside
a grounded shroud would certainly couple your antenna wire to it. You could
also experiment with an inverted-vee using a flag halyard as the top point
and coming down fore and aft with it. Wouldn't cost anything to try that.

Jack

SSB Antenna
 

I have found room on a couple of cats to install a Morad 31' whip
antenna...used an automatic tuner (transmatch) with excellent results.

Best regards-
Charlie

SSB Antenna
 

The grounded shroud will definately couple with the antenna so that's
not a good approach. I use a 23' Shakespere whip with great results.
I've also rigged a separate antenna from the masthead down to the
radar arch. I used 3/16" SS rigging wire with insulators top
and bottom (just like an insulated backstay). At the bottom I placed
a SS spring so that mast pumping would not break the antenna.
Worked great!

Doug
s/v Callista

"Garland Gray II" wrote in message
news:FuM9c.17580$Ft.5252@lakeread02...
They say there is no such thing as a stupid question, but I'm going to put
that theory to a real test.
I have removed a shroud from my catamaran to install insulators so it can
be
used as the SSB antenna. Since there is no backstay as such, a main shroud
will have to do. However, I now find that the sparmaker who rigged the
boat
is somewhat leery of my installing two more potential failure points in a
so
highly loaded and critical support (of course, all are critical). He
suggests using one of the lowers, but these just won't be very long.
In the end I expect I'll continue with the original plan to insulate a
main
shroud, but a thought came to me. The shrouds are inside a thick walled
plastic tube (which I had planned on removing), so I've wondered if rather
than using insulators I retain the plastic tube and secure a wire...or 2
or
3... along the length of the plastic tube as the antenna? I suppose the
presence of the grounded wire inside would interfere with the signal,
maybe
not. Would it work?

SSB Antenna
 

Thanks for the response Jack; I figured it wouldn't work, but had to ask!
I've got way too much roach, esp up high, not to hit, unless I fastened a
horizontal strut aft at mast head , and use a spring as Doug suggests.

"Jack Painter" wrote in message
news:%MM9c.28362$_U.26259@lakeread05...

"Garland Gray II" wrote in message
news:FuM9c.17580$Ft.5252@lakeread02...
They say there is no such thing as a stupid question, but I'm going to
put
that theory to a real test.
I have removed a shroud from my catamaran to install insulators so it
can
be
used as the SSB antenna. Since there is no backstay as such, a main
shroud
will have to do. However, I now find that the sparmaker who rigged the
boat
is somewhat leery of my installing two more potential failure points in
a
so
highly loaded and critical support (of course, all are critical). He
suggests using one of the lowers, but these just won't be very long.
In the end I expect I'll continue with the original plan to insulate a
main
shroud, but a thought came to me. The shrouds are inside a thick walled
plastic tube (which I had planned on removing), so I've wondered if
rather
than using insulators I retain the plastic tube and secure a wire...or 2
or
3... along the length of the plastic tube as the antenna? I suppose the
presence of the grounded wire inside would interfere with the signal,
maybe
not. Would it work?

Garland,

Without having to hunt high and low for imaginary insulators that would
exceed the design strength of main strouds, consider adding a backstay _as
an antenna_ that splits off at a convenient height to connect to both
stern
points Unless your boom is so long that you could not clear it with any
kind
of backstay,. they could even attach to stern stanchions, as there would
never be a strain on the tie points. That would gain you a little more
clearance from the boom and walking into the antenna, etc. Running
alongside
a grounded shroud would certainly couple your antenna wire to it. You
could
also experiment with an inverted-vee using a flag halyard as the top point
and coming down fore and aft with it. Wouldn't cost anything to try that.

Jack

SSB Antenna
 

Charlie and Doug--
Thanks...I had wondered about a whip but didn't think there would be enough
vertical space back there to provide sufficient support. How high above the
base would a second support be needed?

"Doug Dotson" wrote in message
...
The grounded shroud will definately couple with the antenna so that's
not a good approach. I use a 23' Shakespere whip with great results.
I've also rigged a separate antenna from the masthead down to the
radar arch. I used 3/16" SS rigging wire with insulators top
and bottom (just like an insulated backstay). At the bottom I placed
a SS spring so that mast pumping would not break the antenna.
Worked great!

Doug
s/v Callista

"Garland Gray II" wrote in message
news:FuM9c.17580$Ft.5252@lakeread02...
They say there is no such thing as a stupid question, but I'm going to
put
that theory to a real test.
I have removed a shroud from my catamaran to install insulators so it
can
be
used as the SSB antenna. Since there is no backstay as such, a main
shroud
will have to do. However, I now find that the sparmaker who rigged the
boat
is somewhat leery of my installing two more potential failure points in
a
so
highly loaded and critical support (of course, all are critical). He
suggests using one of the lowers, but these just won't be very long.
In the end I expect I'll continue with the original plan to insulate a
main
shroud, but a thought came to me. The shrouds are inside a thick walled
plastic tube (which I had planned on removing), so I've wondered if
rather
than using insulators I retain the plastic tube and secure a wire...or 2
or
3... along the length of the plastic tube as the antenna? I suppose the
presence of the grounded wire inside would interfere with the signal,
maybe
not. Would it work?

SSB Antenna
 

OK so that idea won't work.
But the lower shroud might be long enough if I put the bottom insulator low
near the chainplate, and then to protect crew from getting shocked/burned ,
cover the shroud from the insulator up a ways with a plastic tube.
Will this insulation adversely affect the radio signal?
Thanks for the help.
"Garland Gray II" wrote in message
news:FuM9c.17580$Ft.5252@lakeread02...
They say there is no such thing as a stupid question, but I'm going to put
that theory to a real test.
I have removed a shroud from my catamaran to install insulators so it can
be
used as the SSB antenna. Since there is no backstay as such, a main shroud
will have to do. However, I now find that the sparmaker who rigged the
boat
is somewhat leery of my installing two more potential failure points in a
so
highly loaded and critical support (of course, all are critical). He
suggests using one of the lowers, but these just won't be very long.
In the end I expect I'll continue with the original plan to insulate a
main
shroud, but a thought came to me. The shrouds are inside a thick walled
plastic tube (which I had planned on removing), so I've wondered if rather
than using insulators I retain the plastic tube and secure a wire...or 2
or
3... along the length of the plastic tube as the antenna? I suppose the
presence of the grounded wire inside would interfere with the signal,
maybe
not. Would it work?

SSB Antenna
 

Hayn has just introduced a rigging insulator that has a 'failsafe' feature.
If the insulating portion fails, the fitting stays together at full
strength. It will loosen a bit, and you will have to tighten your
turnbuckle, but it doesn't come apart. I haven't seen these yet, but their
other fittings are very high quality. You can see the new insulator at
http://www.hayn.com/marine/rigging/insulator.html. This may take away some
of your riggers frowns.

Rusty O

SSB Antenna
 

"Rusty O" wrote in message
ink.net...
Hayn has just introduced a rigging insulator that has a 'failsafe'
feature.

Failsafe isolators already exist for, what, 100 years? The famous ceramic
egg-isolator does just that. See
http://www.sijambo.com/zeilen/gabber...achterstag.jpg
for a modern plastic variant.

Meindert

SSB Antenna
 

You will need as much separation as possible...3' is the minimum, 5' to 6'
would be much better. You may have to be creative on the placement of the
upper support with a standoff from the radar arch, off the hand rail, etc.
but you should be able to work it out. I have found room on two 36'
Endeavour Cats; one power one sail.
Good luck-
Charlie

SSB Antenna
 

Yes, I know about 'egg' insulators, I've been using them in communication
systems for 45 years myself.

The Hayn insulator is 'failsafe' without wrapping the wires through loops.
And it's available with eye, toggle, swage, and do-it-yourself ends.

Rusty O

SSB Antenna
 

I'm sure there will be a lot of serious, well-meaning naysayers for the
following, but backstay insulators have virtually become obsolete on most
offshore racing boats in this area. The subsitute is a kevlar backtay with
a ordinary wire(e.g., #14 stranded, tinned) either encased in the protective
cover or taped to the exterior. I just completed a 1220 nmi race with this
arrangement, and I know of several other boats which used the same setup.
The kevlar rigging line is available in a protective pvc casing and is
standard rigging material for modern race boats. It is typically stronger
than the wire or rod that it replaces, much lighter, and has similar life
expectancy. Oh, and the price of my new backstay was approximately half of
the cost of addition of insulators to my existing rod backstay.

Now I will admit that there is a difference between replacing a backstay
with kevlar and replacing a shroud, but I would consult with a professional
rigging service on this possibliity. This might be another alternative, and
less expensive.


"Rusty O" wrote in message
ink.net...
Hayn has just introduced a rigging insulator that has a 'failsafe'
feature.
If the insulating portion fails, the fitting stays together at full
strength. It will loosen a bit, and you will have to tighten your
turnbuckle, but it doesn't come apart. I haven't seen these yet, but their
other fittings are very high quality. You can see the new insulator at
http://www.hayn.com/marine/rigging/insulator.html. This may take away some
of your riggers frowns.

Rusty O

SSB Antenna
 

In article FuM9c.17580$Ft.5252@lakeread02,
"Garland Gray II" wrote:

They say there is no such thing as a stupid question, but I'm going to put
that theory to a real test.
I have removed a shroud from my catamaran to install insulators so it can be
used as the SSB antenna. Since there is no backstay as such, a main shroud
will have to do. However, I now find that the sparmaker who rigged the boat
is somewhat leery of my installing two more potential failure points in a so
highly loaded and critical support (of course, all are critical). He
suggests using one of the lowers, but these just won't be very long.
In the end I expect I'll continue with the original plan to insulate a main
shroud, but a thought came to me. The shrouds are inside a thick walled
plastic tube (which I had planned on removing), so I've wondered if rather
than using insulators I retain the plastic tube and secure a wire...or 2 or
3... along the length of the plastic tube as the antenna? I suppose the
presence of the grounded wire inside would interfere with the signal, maybe
not. Would it work?




The main ingerdiant for an MF/HF antenna is Electrical Length. If the
antenna is to short, it will not radiate properly in the MF portion of
the RF Spectrum. Yes, the autotuner will match a short antenna to the
radio, but it will not help the short antenna radiate that power
efficently. Longer is Better. Insulated shrouds can be effective
Antennas for marine use. It will not matter if the conductive
material is covered with insulative material. What wouldn't work
is to string and insulated antenna wire along a grounded shroud or
backstay, as the mutual coupling would destroy any RF Radiation.
I really liked the Kevlar Backstay with the antenna wire, either
inside, or alongside the length of the backstay. That is a very nice
idea, and would work well. I might suggest that one could add to
the Electrical Length, by using a spiral wrap on the antenna wire
over the Kevlar Backstay, as a way to improve the RF Radiation
Effecency of such a system.

Bruce in alaska
--
add a 2 before @

SSB Antenna
 

I've been told by riggers that the insulator's strength exceeds that of the
stay itself. Might be interesting to hear from anybody that has directly
experienced a failure of an insulator. I've never heard or read of such
a failure.

Doug
s/v Callista

"Garland Gray II" wrote in message
news:FuM9c.17580$Ft.5252@lakeread02...
They say there is no such thing as a stupid question, but I'm going to put
that theory to a real test.
I have removed a shroud from my catamaran to install insulators so it can
be
used as the SSB antenna. Since there is no backstay as such, a main shroud
will have to do. However, I now find that the sparmaker who rigged the
boat
is somewhat leery of my installing two more potential failure points in a
so
highly loaded and critical support (of course, all are critical). He
suggests using one of the lowers, but these just won't be very long.
In the end I expect I'll continue with the original plan to insulate a
main
shroud, but a thought came to me. The shrouds are inside a thick walled
plastic tube (which I had planned on removing), so I've wondered if rather
than using insulators I retain the plastic tube and secure a wire...or 2
or
3... along the length of the plastic tube as the antenna? I suppose the
presence of the grounded wire inside would interfere with the signal,
maybe
not. Would it work?

SSB Antenna
 

That is a good idea. I don't think I would want to use that for a shroud,
but maybe one could insert a length of 6X19 ss in the core of Warpspeed for
a topping lift. It would be a pain to deal with the connection to the tail,
and perhaps there'd be other problems.

"maxlynn" wrote in message
news:63_9c.63659$cx5.47538@fed1read04...
I'm sure there will be a lot of serious, well-meaning naysayers for the
following, but backstay insulators have virtually become obsolete on most
offshore racing boats in this area. The subsitute is a kevlar backtay
with
a ordinary wire(e.g., #14 stranded, tinned) either encased in the
protective
cover or taped to the exterior. I just completed a 1220 nmi race with
this
arrangement, and I know of several other boats which used the same setup.
The kevlar rigging line is available in a protective pvc casing and is
standard rigging material for modern race boats. It is typically stronger
than the wire or rod that it replaces, much lighter, and has similar life
expectancy. Oh, and the price of my new backstay was approximately half
of
the cost of addition of insulators to my existing rod backstay.

Now I will admit that there is a difference between replacing a backstay
with kevlar and replacing a shroud, but I would consult with a
professional
rigging service on this possibliity. This might be another alternative,
and
less expensive.


"Rusty O" wrote in message
ink.net...
Hayn has just introduced a rigging insulator that has a 'failsafe'
feature.
If the insulating portion fails, the fitting stays together at full
strength. It will loosen a bit, and you will have to tighten your
turnbuckle, but it doesn't come apart. I haven't seen these yet, but
their
other fittings are very high quality. You can see the new insulator at
http://www.hayn.com/marine/rigging/insulator.html. This may take away
some
of your riggers frowns.

Rusty O

SSB Antenna
 

Thanks to all who replied; your answers have helped me determine that if I
go for maximum space between insulators on the lower shroud, I can get 26 or
more feet, and then cover the shroud where it can be reached by crewmembers.
I may be worrying too much about using the main shroud because the
insulators are plenty strong, but with the wire connection being the weak
point, I'd end up having 3 times as many on that shroud
"Garland Gray II" wrote in message
news:FuM9c.17580$Ft.5252@lakeread02...
They say there is no such thing as a stupid question, but I'm going to put
that theory to a real test.
I have removed a shroud from my catamaran to install insulators so it can
be
used as the SSB antenna. Since there is no backstay as such, a main shroud
will have to do. However, I now find that the sparmaker who rigged the
boat
is somewhat leery of my installing two more potential failure points in a
so
highly loaded and critical support (of course, all are critical). He
suggests using one of the lowers, but these just won't be very long.
In the end I expect I'll continue with the original plan to insulate a
main
shroud, but a thought came to me. The shrouds are inside a thick walled
plastic tube (which I had planned on removing), so I've wondered if rather
than using insulators I retain the plastic tube and secure a wire...or 2
or
3... along the length of the plastic tube as the antenna? I suppose the
presence of the grounded wire inside would interfere with the signal,
maybe
not. Would it work?

SSB Antenna
 

I believe that 23' is the minimum recommended for the SGC and
ICOM antenna tuners. As I mentioned earlier, I use a 23' whip
fed by an ICOM antenna tuner and it works great.

Doug, k3qt
s/v Callista

"Garland Gray II" wrote in message
news:_6oac.41975$Ft.5165@lakeread02...
Thanks to all who replied; your answers have helped me determine that if I
go for maximum space between insulators on the lower shroud, I can get 26
or
more feet, and then cover the shroud where it can be reached by
crewmembers.
I may be worrying too much about using the main shroud because the
insulators are plenty strong, but with the wire connection being the weak
point, I'd end up having 3 times as many on that shroud
"Garland Gray II" wrote in message
news:FuM9c.17580$Ft.5252@lakeread02...
They say there is no such thing as a stupid question, but I'm going to
put
that theory to a real test.
I have removed a shroud from my catamaran to install insulators so it
can
be
used as the SSB antenna. Since there is no backstay as such, a main
shroud
will have to do. However, I now find that the sparmaker who rigged the
boat
is somewhat leery of my installing two more potential failure points in
a
so
highly loaded and critical support (of course, all are critical). He
suggests using one of the lowers, but these just won't be very long.
In the end I expect I'll continue with the original plan to insulate a
main
shroud, but a thought came to me. The shrouds are inside a thick walled
plastic tube (which I had planned on removing), so I've wondered if
rather
than using insulators I retain the plastic tube and secure a wire...or 2
or
3... along the length of the plastic tube as the antenna? I suppose the
presence of the grounded wire inside would interfere with the signal,
maybe
not. Would it work?