luc wrote:
I read in Practical Sailor about radar, and their reccomendations were
the Furuno 1715 (? I think), and not rated as good was the 1623. I
have a race boat, and want a radar, but as small and light as possible.
While sailing aboard Derek Baylis, a Wylie Cat 65 this past weekend, I
asked the captain what he thought of the 1623, since that is what was
on board. He answered that it was the worst piece of junk for a radar
he's ever seen, and he has much experience. Here I was ready to buy
one, but now not so sure about the 1623.

A few questions. Is there another small radar that is good? Is the
quality of the radar directly related to the size of the radome? What
are the pros and cons of locating a radar on short mast aft, as many
cruisers have, or on the main mast of a sloop?

thanks for any help,

Luc

Hi Luc,

The size of the radar antenna is very much related to the ability to get
good "resolution". There are many different examples, here are a couple:
A small gap looks like straight land line (until you get very close),
Two nearby boats or objects looks like one single boat. Objects apear
bigger than they are.

There is a value in the specs that you can search for. Its called
Horizontal Beamwidth in english. The bigger the antenna the higher the
liklyhood that this value is small. The smaller the value the less
extended objects will appear on the screen - the better the resolution.

You will probably find radomes with values between 3 and 7 degrees. You
dont need to bother too much about the vertical beamwidth. Its usally
arround 20+ degrees. Watch out if it gets much lower since you might
then have difficulties getting a good reading in a small boat during
high sea.

Garmin GMR21 radome horizontal beamwidth = 3,6 degrees.
Garmin GMR404 open array horizontal beamwidth = 1,1 degrees.

I would of course like to have the 1,1 degrees but it would come at a
very high cost and a very bulky antenna. One that you can hit your head
on when it spins (yes this happens more often than one would think) and
wouldnt work well on most sail boats.

there are of course other aspects as well. How well they push back the
side lobes and how fast the pulse rate can be and that the pulse rate
changes with the range setting. Oh yeah, how fast they rotate. The
faster you go on the water the faster you want the radar to spin, since
this affects how fast your screen image will upate. Low-end radars
update once ever two seconds (it actually updates all the time but it
takes two seconds for the radar to update the whole image from 0 - 360
degrees).

Automatic tune, gain, rain clutter and sea clutter can be good but
people who dont like to rely on this probably want solid knobs they can
use to change these values, not having to dig arround in menus.

The "worst" radar I have tried was some sort of no-name radar with black
and white lcd screen and probabaly a horizontal beamwidth of 7 degrees.
The shorest range was 0.250nm. But it still worked great and did the job
in the fog! Its sooo much better than no radar at all

I dont know if you will be using the radar in-doors or out-doors. Maybe
that will affect the type of screen you go for. Night time there's no
problem with sunlight that would normaly cause a problem for LCD's. But
I dont really know because all the LCD's I've used was indoors.

Regards
david