Larry,
Thank you very much. I can do this easily, as the deck is contructed as a
steel space frame underneath and the deck is marine ply covered in teak. In
the aft cabin, I have 8' of headroom and can fasten the coupler to the
deckhead in the center of the span between the chain plates. I can maintain
a 6 inch spacing between the antenna feeds and any steel structure.
Steve

"Larry" wrote in message
...
"Steve Lusardi" wrote in
:

Bruce & Larry,
Ok the whip won't cut it. The back stays are 90'+ each. Do I use 1
inverted V or do I use each back stay as antennae?
Steve



Parallel them. Put an insulator about 3' from the upper end, not too
close to the metal up there, then an insulator on each of the bottom ends
right above the deck but not so the backstay touches bimini tops, etc.
That wonderful steel hull is the finest ground plane on the planet hooked
to that ocean like it is. No grounding blocks or other nonsense is
necessary. RF goes right through bottom paint on steel hulls.

Put the tuner in the middle of them at the bottom and be SURE to use
EQUAL LENGTH FEED WIRES to the base insulators of each so they are fed in
phase. This creates an effective radiating conductor diameter as wide as
these are far apart....making it broadbanded as hell, a really good
thing.

"Feed Wires" ARE part of the ANTENNA and are NOT a transmission line. Do
not try to use coax cable all neatly tywrapped to the grounded rigging
between the tuner antenna insulator and the backstays. This is CRAZY!
Use #10 or larger insulated conductors, NOT SHIELDED, as short as you can
get them and as far away from anything metal as you can get it.

If you come through the steel hull with these antenna wires, we need a
fairly large hole with a feed-thru insulator to guide the RF away from
the grounded hull.
http://www.surplussales.com/Antennas/Antennas-6.html
Look at ICR 9548 near the top of this insulator page. The 4" "beehive"
goes on the outside of the boat. This makes a very long leakage path in
the wet outside environment and the smaller inside-the-hull side keeps
the hot RF wires away from the hull. Try NOT to come off these at 90
degree angles on either end. RF doesn't like to turn corners....come off
the insulator straight out with a bent lug then make a smooth curve where
you have to go, as much as practical. The hole in the hull is large to
reduce the capacitance between the high impedance RF high voltage and the
grounded hull sucking off your signal.
NO - sticking a piece of the center conductor covered with its poly core
in a hole in the hull is NOT acceptable. The poly won't last a year in
the sun, anyways.

Notice how important it is to keep the antenna wire between the tuner and
backstays away from the metal:
http://www.surplussales.com/Antennas/Ceramic_stof.html
Ol' Navy sure does a nice job of it....(c; DO NOT TYWRAP THE ANTENNA
WIRE TO ANYTHING METAL! Standoff insulators can be nicely made of common
white PVC water pipe and fittings. 3-4" stood off is great but only for
SHORT distances.

Your insulated backstay antenna is like most AM broadcast stations,
except AM stations use a resonant tower. Your 90' long backstay will be
self resonant on 234/90 = 2.6 Mhz and will radiate like mad around that
frequency in the old 2 Mhz marine band.... If we move the insulators down
from the top so there is great radiation in the 4.1 Mhz marine band, the
insulators should be 234/4.1 = 57' of backstay between them. The tuner
will make it tune the other bands by adding inductance and capacitance in
series and parallel. But, nothing radiates as good as a resonant
antenna. At 57' 1" long, that top insulator will also be far away from
the RF-draining mast. Go for it!..(c;

I like the 4 Mhz tuning because most all Caribbean yachties talk on that
band. It's useless in the daytime but at night you get solid coverage
from where you are straight out 500 miles in all directions. 4 Mhz
tuning also resonates the antenna at 3/4 wavelength on 12.3 Mhz, the best
DAYTIME marine band, too. You get two great resonant points at 57' 1".

Larry
--
QUOTE OF THE MONTH:
"I have been to several major Chinese cities and have seen first hand
shops crammed with obviously fake American products." - Jon Dudas,
Undersecretary of Commerce for Intellectual Property Rights.

How can they be fake? The Chinese make all "American Products" I use!