Larry,
The boat is a 60' steel sloop and since I built it, I can guaranttee the
chain plates are very securely welded to the hull structure. I will order
one and see how it's made. Moisture could certainly be an issue, but it is
certainly worth a try.
Steve

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

Larry,
Excellent explanation, but I would like to know if I understood it
correctly. I believe you stated that ,yes, some radiation would be
lost with the slightly out of phase, grounded stay, coupled current
radiation, but you did not state how much of a performance impact this
would make. As I have an SEA 330, I have power to spare on the
transmitter side, but the split lead antenna's receive performance was
not mentioned, nor any effect this arrangement would make in its
omni-directional ability. I guess the question I need to answer, is
this an affordable alternative to the insulated stay? Could you
elaborate? Steve



Oh, it probably works just fine. Shunt fed antennas have worked great
for years. The problem I see in it is more related to how are we going
to keep seawater out of the insulating material between his feed and the
stay to keep the tuning stable and to keep the wet device from arcing on
some frequencies where it's at a high impedance point.

The only real way to tell how well it works is to just order it and
install it TEMPORARILY WITHOUT THE HOLES and try it out on your
backstay. If it works, install it. If not, send it back and get a
refund.

Are you SURE your backstay is grounded at the BOTTOM? That would be
very unusual in a production boat.

I'd say before you send him all this money, let's hook the RF output of
the SEA autotuner directly to the bottom of the backstay and any kind of
ground right there at the dock. Just run a jumper cable from the tuner
ground post to the engine block as directly as you can to test it. If
the bottom of the backstay is grounded it simply won't find a tuning,
especially on the lower bands. just sit the grounded tuner under the
backstay on the seating, anyplace it won't fall overboard is fine, but
as close to the backstay as you can temporarily located it. Keep the
wire from the tuner's high voltage output to the backstay as short as
possible. Listen to the receiver AFTER pushing the TUNE button and
letting the autotuner find a tuniing solution as tuning also affects
reception. If it will tune and seems to receive well, call someone at
some distance, not in your area, that you've prearranged to have
listening on the phone, maybe a couple of hundred km away. Connect the
cellphone to them so you can listen to your own signal at a
distance....above 6 Mhz in daytime, below 6 Mhz at night.

If it works, just install it! Problem solved!

If you can't find a way to get a ground to the temporary installation,
that's easy, too. Drop an anchor chain over the side and let it lay on
the bottom under the boat. Boy does THAT make a great ground! I use a
trailing wire about 30 meters long behind the boat under sail at sea.
It's just a plastic covered #16 piece of hookup wire the end of which
has been dipped in sealer so the water can't get up into it and rot the
wire. I did have a can lid on the end of it making a little sea anchor
to hold it out behind the boat, but SOMETHING BIG fell in love with that
and SWALLOWED it and half my ground wire! He must have needed iron in
his diet...(c;

On Sat, 13 Sep 2008 06:00:26 +0000, Larry wrote:

BOTH WCBS and WFAN in New York City transmit on 660 Khz and 880 Khz
through that little piece of copper tubing coming out of the tuning
house

I moored my first keelboat about 300 yards from that antenna back in
1971. It's located on a rocky little island barely bigger than the
transmitter shack.

On Sat, 13 Sep 2008 09:08:25 +0200, McGuffin wrote:

So basically an insulated backstay comes out as the best solution.
(I don't like the idea of cutting my stays though...)

There are thousands of sailboats out there using insulated backstays
with good results. Offshore racing boats are required to have a whip
antenna as backup in case of a dismasting.

Wayne.B wrote in
:

On Sat, 13 Sep 2008 06:00:26 +0000, Larry wrote:

BOTH WCBS and WFAN in New York City transmit on 660 Khz and 880 Khz
through that little piece of copper tubing coming out of the tuning
house

I moored my first keelboat about 300 yards from that antenna back in
1971. It's located on a rocky little island barely bigger than the
transmitter shack.



If you tune the mast to one or the other frequency, you can probably get
more than enough low frequency RF to rectify and recharge the house
batteries at their expense....(c;

I used to know a ham that lived just off the business end of the 3-tower
directional array of WKBW in Hamburg, NY (Buffalo's Rock-N-Roll blowtorch).
His yard lights and garage lights ran off a 1520 Khz-tuned big loopstick in
the attic off KB's nice signal, 24/7. To "dim" the lights (and keep the
overmodulated rock music from blowing the bulbs), you adjusted the tuning
off peak until you got the brightness you wanted, as well as bulb
longevity. He ran it that way for years. If one bulb blew, the excess
voltage that loss of load caused usually took out most of them...(c;

The closest house to WWKB's main lobe, now, can be measured with Google
Earth's measuring stick to be about 134 feet from a 50,000 watt AM
transmitter's DIRECTIONAL, much more intensive, output. I bet those people
don't even need a radio to listen to what their teeth are saying...(c; If
I lived in that house, I'd be running a high powered electronic switcher to
convert 1520 Khz into 60 HZ to run the house...(c;

Think about that the next time you're reading some sellphone propaganda
telling you your sellphone is frying your brains with .12 watts of power,
in an effort to get support from the users to turn the power down even
further at the expense of customer range and usefulness. If what sellphone
company say is true, all the people on the street would be fried!