I had a JRC 1000 on my first boat and now I am restoring a 43 Endeavour
ketch and it is time to think about radars. The JRC was a nice unit but
woefully underpowered. I would like to see out 8 to 10 miles with the
radome mounted 20-30' up the mizzen. I know that the 4kw will give more
power out and thus burn thru in foggy conditions but most of the 4kw units
have the big displays. Everyone on this group knows the drill...what will
give me the biggest bang for the buck with the best reliability amd a thin
small display.
Thanks
Bruce

--
Shield Finishes and Nauticoat Marine Finish Systems
www.shieldfinishes.com

Bruce on horizon wrote:
I had a JRC 1000 on my first boat and now I am restoring a 43 Endeavour
ketch and it is time to think about radars. The JRC was a nice unit but
woefully underpowered. I would like to see out 8 to 10 miles with the
radome mounted 20-30' up the mizzen. I know that the 4kw will give more
power out and thus burn thru in foggy conditions but most of the 4kw units
have the big displays. Everyone on this group knows the drill...what will
give me the biggest bang for the buck with the best reliability amd a thin
small display.

The RayMarine equipment lets you mix and match the displays and the
domes so you get what you need now, and upgrade later. BTW, the radar
horizon is about 7 miles from a transmitter 30 feet up. Large targets
will of course be seen at a larger distance, but I can't say that I've
had any problem with my low power Raytheon, and I cruise in Maine and
Cape Cod.

Jeff Morris wrote:
Bruce on horizon wrote:

I had a JRC 1000 on my first boat and now I am restoring a 43
Endeavour ketch and it is time to think about radars. The JRC was a
nice unit but woefully underpowered. I would like to see out 8 to 10
miles with the radome mounted 20-30' up the mizzen. I know that the
4kw will give more power out and thus burn thru in foggy conditions
but most of the 4kw units have the big displays. Everyone on this
group knows the drill...what will give me the biggest bang for the
buck with the best reliability amd a thin small display.


The RayMarine equipment lets you mix and match the displays and the
domes so you get what you need now, and upgrade later. BTW, the radar
horizon is about 7 miles from a transmitter 30 feet up. Large targets
will of course be seen at a larger distance, but I can't say that I've
had any problem with my low power Raytheon, and I cruise in Maine and
Cape Cod.

I've had minor second thoughts on this after checking the specs. In the
"old days" more powerful domes were heavier and used more power - that
is not the case now - the 4kW Raymarine dome only weighs a few pounds
more and uses 1 or 2 Watts more juice.

I'm still not sure of the value for long distance viewing, but the high
power dome will have finer resolution, so that a pair of channel buoys
will be resolved as two targets further away with the more powerful
unit. Navigation is easier, since coastlines will more closely resemble
the chart. However, this takes a lot of practice and you're better off
relying on a good gps.

The downsides of the large unit is almost double the cost (a $1000
premium on the RayMarine list) and a much larger dome (an issue for
those trying to hide the dome from the jib).

In article ,
Jeff Morris wrote:

I'm still not sure of the value for long distance viewing, but the high
power dome will have finer resolution, so that a pair of channel buoys
will be resolved as two targets further away with the more powerful
unit. Navigation is easier, since coastlines will more closely resemble
the chart. However, this takes a lot of practice and you're better off
relying on a good gps.


The above is due to a narrower Horizontal Beamwidth, and not the PPP
(Peak Pukse Power) of the transmitter. Radar OEM's tend to put the
bigger antennas (narrower Horizontal Beamwidth) on their Larger PPP
transmitters as a rule, but the two are mutually exclusive
specifications. Third and fourth Generation Marine Radars, all have
Log Recivers, SolidState Frontends, and that is why they preform
as well as the older Second Generation Radars that had twice the PPP
in the transmitters. Where it used to take 10Kw and a 6 Ft SlotLine
antenna to pickup 48 mile targets in second genertion Marine Radars,
the 4Kw 4Ft Slotline antennas of the Fourth Generation work just fine
on the same paths. Like wise the 2Kw 3Ft Slotline Radars of the Third
Generation will compare very nicely with a 2Kw flatpanel antennas of
todays small boat radars, with the exception of the very wide Horozontal
Beamwidths of those flat panel antennas, that can't differentiate between
two targets at the same distance, but closer than 6 or 7 degrees in
bearing.


Bruce in alaska
--
add a 2 before @

Jeff Morris wrote in
:

I've had minor second thoughts on this after checking the specs. In the
"old days" more powerful domes were heavier and used more power - that
is not the case now - the 4kW Raymarine dome only weighs a few pounds
more and uses 1 or 2 Watts more juice.

Pot metal and plastic is much lighter, which is what the Raymarine is made
from. They'll replace it when the pot metal consumes itself from the
condensation of breathing in and out through the drain tube makes it rain
inside the dome, though. We're on our third...(sigh)

The communications on the RL70CRC also failed, which explains why we
couldn't get the Seatalk Gyro/Compass to ever calibrate properly, no matter
how many times we turned it slowly. They fixed that, too, but I don't
think it was ever working right in the first place.

Isn't it amazing how 2,000 watts of peak RF power just appears from thin
air for only 1-2 watts more DC? Magic? Divine intervention? Maybe its
the printer stepper motor that turns the rubber band that drives the PC
board antenna array...??


I'm still not sure of the value for long distance viewing, but the high
power dome will have finer resolution, so that a pair of channel buoys
will be resolved as two targets further away with the more powerful
unit. Navigation is easier, since coastlines will more closely resemble
the chart. However, this takes a lot of practice and you're better off
relying on a good gps.

Ah, but you have another problem in the fog. The higher the antenna, the
further away the target will disappear as the target approaches the boat!
You won't see the bouy 8 miles away with the antenna down low, but you WILL
see the bouy in the fog a LOT closer to the boat as you, hopefully, pass
it.

Traveling at Mach 1, I'd understand having more range. But, traveling at 6
knots I'd rather see that target two boatlengths off the port bow with a
lower-down antenna....wouldn't you?


The downsides of the large unit is almost double the cost (a $1000
premium on the RayMarine list) and a much larger dome (an issue for
those trying to hide the dome from the jib).


I'm tired of changing out pot metal Raymarine antenna pods. There's gotta
be a way to build a $2000 radar transceiver that isn't made out of the same
materials as the window winder in a '97 Ford pickup. The damned chassis
it's all mounted in is made of ZINC!! Idiots.... Look inside for
yourselves! Don't trust me. Unscrew the 4 little flathead screws and take
the top of the dome off. Do it on that boat down the dock and see if it's
wet inside!

Furuno? Anyone had water destroy a Furuno radar dome??

"Larry W4CSC" wrote in message

Ah, but you have another problem in the fog. The higher the antenna, the
further away the target will disappear as the target approaches the boat!
You won't see the bouy 8 miles away with the antenna down low, but you
WILL
see the bouy in the fog a LOT closer to the boat as you, hopefully, pass
it.

Traveling at Mach 1, I'd understand having more range. But, traveling at
6
knots I'd rather see that target two boatlengths off the port bow with a
lower-down antenna....wouldn't you?

I have to wonder how serious a problem this really is.
For instance, if I can run between two buoys spaced 300' with a scanner
that's over 100' in the air and watch them pass down my side, how much
difference can there be with a small boat and a scanner placed 30' up,
unless you are totally crowding the buoy to one side (not good).
Also, by that point, if you lose sight of the buoy, you should have all
ready changed your concentration to some new point or reference, ahead.

otn

In article . net,
"otnmbrd" wrote:

I have to wonder how serious a problem this really is.
For instance, if I can run between two buoys spaced 300' with a scanner
that's over 100' in the air and watch them pass down my side, how much
difference can there be with a small boat and a scanner placed 30' up,
unless you are totally crowding the buoy to one side (not good).
Also, by that point, if you lose sight of the buoy, you should have all
ready changed your concentration to some new point or reference, ahead.

otn

OTN, the Horozontal Beamwidth of your Commercial Maritime Radar is
significantly smaller than that of the units found on most Pleasure
type vessels. That makes a HUGH difference in the Target Discrimination
Ability between the two radars. Apples and Oranges, here.......


Bruced in alaska
--
add a 2 before @

On Tue, 15 Feb 2005 04:44:49 GMT, Larry W4CSC wrote:


Furuno? Anyone had water destroy a Furuno radar dome??

OK, crap construction drives me nuts, particularly when it's something
(like a radar) which MUST spend its working life out in the elements.

Assuming the radar itself isn't absolute crap...like that "Mars Bar"
radar the Brits made 25 years ago, say...what is *your* radar of
choice for durability? 'Cause once I go up the mast, I don't want
anything short of a hurricane to cause damage to that radome...

My buddy swears by his old Kodan CRT unit, but he's got a big ketch
and more room and power than most people to play with. The thing is a
toaster-sized box bolted to his coaming, and it takes skill to use it,
but if you can learn that skill, it's accurate as hell.

R.

In article ,
rhys wrote:

On Tue, 15 Feb 2005 04:44:49 GMT, Larry W4CSC wrote:


Furuno? Anyone had water destroy a Furuno radar dome??

OK, crap construction drives me nuts, particularly when it's something
(like a radar) which MUST spend its working life out in the elements.

Assuming the radar itself isn't absolute crap...like that "Mars Bar"
radar the Brits made 25 years ago, say...what is *your* radar of
choice for durability? 'Cause once I go up the mast, I don't want
anything short of a hurricane to cause damage to that radome...

My buddy swears by his old Kodan CRT unit, but he's got a big ketch
and more room and power than most people to play with. The thing is a
toaster-sized box bolted to his coaming, and it takes skill to use it,
but if you can learn that skill, it's accurate as hell.

R.

Give me a Furuno, over any other third and fourth generation Radar OEM
and a Decca over any second generation Radar. First generation radars
were all crap, and the fifth generation is just now coming out, so no one
knows yet who has the best stuff.......

Bruce in alaska
--
add a 2 before @

On Tue, 15 Feb 2005 04:44:49 GMT, Larry W4CSC wrote:


Isn't it amazing how 2,000 watts of peak RF power just appears from thin
air for only 1-2 watts more DC? Magic? Divine intervention? Maybe its
the printer stepper motor that turns the rubber band that drives the PC
board antenna array...??

Not sure about the merits of this beef.
A radar with a pulse repetition period of 1 millisecond, and a pulse
width of 1 microsecond has a peak power about a thousand times greater
than its mean power - and this is a standard feature of pulse
radars....

Brian Whatcott Altus OK