In article ,
"Fred Miller" wrote:

More important then larger screen is open versus closed array (open gives
better target discrimination;i.e. a tug and barge appear as two separate
targets instead of one large one) and most important, power. A 4KW radar is
the lowest practical level if you want to be able to burn thru heavy
rain/snow. I would choose both of these before I invested in a color radar.
FYI I own a 10 inch screen, 6 foot open array with 10 KW on my boat in
monochrome and would NOT trade it for a 4 KW color unit.

Yes to all the above. Reason that open arrays work better than closed
arrays, is really simple. It is hard to put a big slotline antenna
inside a Radome. It is the bigger antenna, that gives better target
resolution, because the bigger antenna has a narrower Horozontal
Beamwidth. If your radar antenna has a smaller Horozontal Beamwidth than
the next guys it will have more gain and much better target resolution.
I really like the 6ft or 10ft Xband Slotline antennas that Furuno
uses. They are in the 1.5 to 2 degree beamwidths. As for power
4Kw will work just fine for ranges under 6 miles no matter what the
weather is like, in Xband, with the solidstate logarythmic receiver
frontends that are standard in commercial radars today. Most boats
just don't need more than that. For Inspected Vessels under SOLAS
Requirements maybe a 10Kw transmitter is valid, but not really needed.
Ranges longer than 12 miles are really not required for radars that are
less than 20ft off the water because the only thing they see out that far
are mountains, and you should be using a GPS to tell you where you are,
and the radar to keep you from bumping into that are moving around.


Bruce in alaska
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