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 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

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

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?

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

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?

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?

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

"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

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