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From: Bryan Genez (no email)
Date: Thu May 01 2008 - 17:46:38 EDT
Increased range with height of antenna is overrated. If you're standing in
your cockpit, and your eyes are 8 feet above the waterline, your horizon
distance is about 3.3 nautical miles. Raise your height to 40 feet above
the waterline, and you add just four miles to that number (to 7.3 NM).
There's another practical problem with high antennas. The cable between the
antenna and receiver is typically about 10 meters long. You can buy longer
cables, but they're expensive. I know....
I've mentioned before, but a significant issue is whether or not to break
that cable and use a watertight connector box somewhere near the base of the
mast. Those connections are very fragile and are the source of many
post-install problems. If you can keep the cable intact, you're much better
off.
My antenna is mast-mounted, about 15 feet above the deck. That's close
enough so a 10-meter cable will reach the receiver at the nav station, and
still high enough to give a good return on shipping and weather. The
staysail gets around it without any problem. However, if I had elected to
mount my receiver in the cockpit or the companionway, I would have needed a
longer cable, or I would have had to build a stern mount.
What will the radar be used for? Tracking weather? Shipping? Navigation?
Probably "yes" to all three. But note that tracking shipping today is much
more effective with AIS. Helpful if you radar is compatible with AIS.
Compromises...compromises.
-- Best, Bryan Genez "Capella" V40-158 New Bern, NC [Non-text portions of this message have been removed]
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