In article ,
"Steve Lusardi" wrote:

Agreed Marc. My point that I was trying to make was that not only does the
6' antenna with its narrow beam help disciminate targets, so does higher
transmit power, even at short range, because of the increased echo strength
increasing the signal to noise ratio of the returning echo.

It may - if the noise is coming from an external source. If the noise is
the water reflecting the transmitter's pulse, it probably does not help,
or does it?

This is very
important, especially in rough water, where the receiver needs all the help
it can get to discriminate a small, perhaps radar absorbing target from the
white caps. It is my belief that these two factors are the most important
points to be aware of when in the market for a new unit. To make my point
even stronger, a 25KW FR2125 Furuno will pick up a paper dixie cup at a 100
meters and an FR2115 at 12KW will not. Both radars are identical in every
respect except the transmitter. You may not attach much importance to this
ability, but the fellow I purchased my masthead rig from decided he would
change from a masthead rig to a fractional on his 70' aluminum sloop the
Dance II out of Southhampton in the UK. Right after the conversion, he set
out to Gibralter for some chartering. At 0200 off the coast of Portugal
making 7 knts he hit a partialy sunken shipping container that he never saw
on his 4KW radar with a 4ft radiator. The Dance II was lost. According to
Lloyds, this is a regular occurance and in a single calendar year hundreds
of containers are lost overboard. Maybe this ability is not important on a
lake, river or canal, but in the open ocean it certainly is.

I wonder if he would have caught it only because of a more powerful
radar. Anyway, containers are a major danger, and I would not want to
hit one.
I guess digital signal processing can make more of a difference, but
this is unfortunately only available at a price.

Marc

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