Rob, in article a999739f-3fe0-4e5a-b019-94c67b451186
@v67g2000hse.googlegroups.com, says...
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?

As others have said, mount it low down with a clear view of
the sky - and well away from the radar transmitter. A
friend's boat had one that was mounted above a radome that
wouldn't work when the radar was running. Apparently, the
cable going up to the GPS antenna routed in front of the radar
antenna wasn't a good idea... :-)

Mounting it high up on a sailing boat also makes it subject to
position reporting error due to heel, not to mention confusing
it when rolling.

--
JohnW.
Replace the obvious with co.uk in 2 places to mail me.