I've had a Furuno 1622 for a couple of years and I'm very pleased with it.
An external alarm is an available option.
There are two features that might sound similar, if you've never used radar,
but they are different: Standby and Watchman.
First, in Standby the system is warmed up and ready to go but the antenna is
not radiating a signal or listening for a return. Because the antenna isn't
being used, there's less power used during Standby. Pressing the Transmit
button starts the antenna and power consumption is increased. The advantage
of Standby is that the system's ready to use when you want it.
Second, Watchman reduces power consumption by cycling the antenna off and
on. You set the length of the off period. If the antenna notices a change in
the returns from the previous on cycle, it stops the Watchman function and
continues to stay on. If you have the optional external alarm, it will be
sounded.
A third nice feature is Guard. You drag the cursor on the display from the
top left corner to the bottom right corner of the area you want to be
monitored. If an object enters that area, the optional external alarm will
be sounded to alert you.



"it's true!" wrote in message
...
Ahoy, I'm considering one of two budget radars for my portly 23'
sailboat. I can support it with a 220ah battery setup, one 70w solar
panel and a 12hp diesel. (30 yr old Yanmar, I don't know the amp
output).
The Furuno 1621 states 36w (3amps) for operation and 8w (.6amps)
standby. Not sure what standby is. About $1200usd
Anyone have figures for the JRC MkII? Anyone have real world figures,
experience or best guesses? About $900.
I have some questions as I have never owned a radar.
1)
Do either of these have some kind of alarm that will buzz if an
obstruction appears within x distance of my boat? There is something
called watchman mode on the Furuno but no specifics are given.
2)
Is there another dedicated device which will draw less power and be
less complicated that might serve as an alarm for approaching tankers
less than 5 miles away for example?
I guess my 25 yr old Passport radar detector won't work for this?
I got caught in dense fog last summer so I definitely want the radar
but I'm also interested in a separate device if the radar sucks too
much battery.
Thanks and smooth sailing.