On Tue, 22 Jan 2008 19:40:30 +1100, Moonshadow
wrote in :

larry wrote:

Wrong attitude. The GPS antenna has no need for ALTITUDE. Aboard
Lionheart, I got tired of them bumping into both the Raystar little dome
and the Garmin active antenna, so I mounted them INSIDE the overhead
cabinet in the galley

Belowdecks is the way to go in a fiberglass boat.

My friend held the antenna alternately in the clear abovedecks, and
belowdecks hard up against the coachroof in various spots. I watched the
signal strength indicator on the chartplotter as she moved the antenna
between the abovedecks and belowdecks positions. In many spots
belowdecks there was no difference in signal strength from the
satellites with the antenna abovedecks or belowdecks.

My GPS antenna is now mounted in a good spot belowdecks, out of the
weather, away from running rigging and flying feet.

My own tests have been quite different -- I've seen considerable
difference between belowdecks and abovedecks, and agree with
manufacturers recommendations to mount the antenna on something like the
stern pulpit. It makes no sense to take _any_ risk with something this
critical to safety.

--
Best regards,
John Navas http:/navasgroup.com

Always best to get the GPS antenna some distance from the radar and out of
the direct beam of the radar.

I agree that low down is generally ok. Mine is inside the fibreglass
flybridge with no apparent ill effects!

Alec


"Rob" wrote in message
...
I have been getting conflicting advice about relative position in
regard to my radar dome. Both will be mounted on my mast about 12 to
24 inches apart. I have a choice of having the GPS right below the
bottom of the dome or I could put an extension and have it extend a
few inches above the dome. Any advice?
Thanks
Bob

Why do people persist in putting their GPS antenna on the stern rail. Is it
not one of your most important instruments? Do you want it to be yanked off
by some clumsy git climbing aboard from a dinghy or clipped off by a
shoreline? I have always mounted mine on the stern but directly on the deck
where it out of everyone's way. It also gets a perfect view of the sky
without the pendulum movement of a mast mounting. This is on my third boat
and I have never had one damaged. How many people keep a spare GPS aerial
for these eventualities?


"Alec" wrote in message
...
Always best to get the GPS antenna some distance from the radar and out of
the direct beam of the radar.

I agree that low down is generally ok. Mine is inside the fibreglass
flybridge with no apparent ill effects!

Alec


"Rob" wrote in message
...
I have been getting conflicting advice about relative position in
regard to my radar dome. Both will be mounted on my mast about 12 to
24 inches apart. I have a choice of having the GPS right below the
bottom of the dome or I could put an extension and have it extend a
few inches above the dome. Any advice?
Thanks
Bob

Nicholas Walsh wrote:
Why do people persist in putting their GPS antenna on the stern rail. Is
it not one of your most important instruments? Do you want it to be
yanked off by some clumsy git climbing aboard from a dinghy or clipped
off by a shoreline? I have always mounted mine on the stern but directly
on the deck where it out of everyone's way. It also gets a perfect view
of the sky without the pendulum movement of a mast mounting. This is on
my third boat and I have never had one damaged. How many people keep a
spare GPS aerial for these eventualities?


Mine's coachroof mounted 'limpet' style on our Contessa 26 with excess
cable shortened and a new BNC plug put on. It's predecessor used to be
mounted on a stancheon supporting the mainsheet horse and that was a
nightmare. If it didn't get knocked by the mainsheet, someone would
lean back over it and block the signal, or a warp would abrade its cable
etc. I give the new one a gentle polish a couple of times a season to
keep the water beading up and running off and I get a *far* better
signal. I've replaced the cable into the old one and tested it for a
spare just in case though.


--
Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED)
ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk
[at]=@, [dash]=- & [dot]=. *Warning* HTML & 32K emails -- NUL:
'Stingo' Albacore #1554 - 15' Early 60's, Uffa Fox designed,
All varnished hot moulded wooden racing dinghy.

On Sat, 26 Jan 2008 18:44:41 -0000, "Nicholas Walsh"
wrote in :

Why do people persist in putting their GPS antenna on the stern rail. Is it
not one of your most important instruments? Do you want it to be yanked off
by some clumsy git climbing aboard from a dinghy or clipped off by a
shoreline? I have always mounted mine on the stern but directly on the deck
where it out of everyone's way. It also gets a perfect view of the sky
without the pendulum movement of a mast mounting. This is on my third boat
and I have never had one damaged. How many people keep a spare GPS aerial
for these eventualities?

In my experience the stern pulpit rail is safer -- I've seen too many
people kick an antenna mounted at deck level.

I always have at least two hand-held units to back up the boat GPS.

--
Best regards,
John Navas http:/navasgroup.com