There are 2 issues here. First, I agree with Fred on the antenna for sure.
The sharper beam definitely delivers better target descrimination. Secondly,
I prefer an analog display over any digital. On a digital display there is
much better contrast, but you are looking at what the computer thinks the
target should be, not necessarily what it really is. The purpose of the grey
scale or color is to deliver to the viewer the strength of the returned
signal.(Target hardness) An analog display on the other hand will allow the
trained operator the ability to play with the gain and clutter controls and
view directly the raw returns and depending on the operator's skill and
experience, decipher more reliable target information than any computer
will. However, skill and experience is the key here. Watch the radar during
a clear day and learn the radar. Now on Bruce's comment on power, he is
correct most of the time, but the higher power will allow the discovery of
burgy bits and partially sunken containers much more reliably than a lower
power one.
Steve

"Bruce in Alaska" wrote in message
...
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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