radar questions
 

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

radar questions
 

There is a review on radars in practical sailor recently. Their high
pick was the furuno 1725(?) I had it a liked it.

Bob

Charlie Morgan wrote:
On 7 Nov 2006 10:29:11 -0800, "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

The 1623 is a very good quality, but small and basic, RADAR. It would
help to know precisely why that captain didn't like it. He may be
comparing it to very large, open array equipped commercial boat RADAR.
No smaller RADAR with a covered array is going to compete with that.
That doesn't make the smaller units junk, though.

What kind of situations do you encounter that RADAR seems like it
would be helpful. Do you cruise as well as race? What sort of areas as
far as traffic, and general conditions?

CWM

radar questions
 

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

radar questions
 

luc wrote: " I have a race boat, and want a radar, but as small and
light as possible"

Luc,

Your concerns/focus are misdirected if your going to focus on small and
light. With a race boat, if your going to do it at all, you should make
it (a) worth doing, e.g. insure your going to get performance you can
use and in doing so consider a 4kw unit (better to see other sailboats
most of which have an unbelieably weak radar return) and a color
chartplotter (radar overlays gps map) to make it more probable you can
make use of the image (b) focus on insuring the radar unit dosn't foul
the sails or add to much weight aloft, e.g. consider mounting the radar
on a pole (adds even more weight) off the stern or mount off the
backstay or if on the mast put a ring around it so your sails or
halyards wont get caught on it, and (c) realize that the weight of the
radome is really inconsequential compared to the mounting hardware and
chartplotter, and inconsequential compared to distorting your wind
instrument results in light air or choppy seas if you mount it high up
in your mast (at a minimum it needs to be a couple of feet above your
boom, so your boom dosn't get caught in the radar return)

My next radar is going to be 4kw, because I am just amazed how my 2kw
can get a strong return from a childs mylar baloon sitting on the
surface of the sea, and is entirely blind to 40 foot and smaller
sailboats, as well as many motor boats.

One thing I am glad I did with my radar, is put it on a self leveling
mount, so I can use it under sail.

Dan





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

radar questions
 

"luc" wrote in news:1162924151.581326.150280
@m7g2000cwm.googlegroups.com:

A few questions. Is there another small radar that is good?

You get what you pay for. It's that simple. More power has more
range..IF it's up high. It can't see over the horizon. Its horizon is
the same as yours on a clear day. The difference is it can see through
fog and in the dark. The stronger its transmitter, the stronger its
returns from the targets and the strong transmitter making stronger
returns can see more at the same distance in bad weather. Read that,
smaller targets, too.

Is the
quality of the radar directly related to the size of the radome?

The larger the antenna array, the narrower its beamwidth (horizontally).
The narrower the beamwidth, the better it is at resolving the target's
position. A wider beam makes an arc of a target on the display, from
angle it starts seeing the target to the angle it loses the signal from
the target. A bigger antenna, with a much narrower beamwidth, cause a
smaller target on the display, raising the accuracy of the bearing of the
target. The narrower beamwidth also turns one wide target on Radar A
into 4 distinct targets from the big antenna on Radar B. B simply
resolves the targets as individuals because the beam is narrow enough to
stop receiving one target before starting to receive the next as it
sweeps by. So, instead of a blob, you get 4 dots showing better
positions. It's all about horizontal beamwidth. We want narrow
horizontal beamwidth but WIDE vertical beamwidth. If the vertical
beamwidth is too narrow, when your boat heels over or pitches and rolls,
none of the beam that's so narrow lights up the target, so no signal
returns and he doesn't show up on the screen. These tilting mounts sound
nice and do, slightly, improve target painting, but the radars' vertical
beamwidth is so wide, by design, you'll see the target out the beams
heeled over 35 degrees, anyways. The tilting mount centers the RANGE of
the allowable vertical tilt it will tolerate.

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?


That's easy. Climb up to where you think you're going to put the radar
while drifting in the harbor. How far can you see? That's how far the
radar can see. It sees targets over the horizon that are tall enough to
come up above the horizon, like tall TV towers, big buildings, water
towers, lighthouses. If you can't see it, the radar can't, either, no
matter what its antenna size and power. It's not magic or clairvoyant.

There's another problem. As you raise up the antenna higher and higher
to see that ship 32 miles away, the vertical beamwidth ends at a higher
and higher altitude, farther and farther from the boat CLOSE IN. From
the top of the mast, that big bouy you're about to run into disappears
from the screen in the fog because the bottom of the radome is a radar
shield to keep from cooking the kids' brains on deck. So, the higher the
radar is located, the further out from the boat the close in targets
disappear because you're shooting the signal right over the top of them.
In a sailboat, I don't get too excited seeing a target over 6 miles away
unless it's doing over 100 miles per hour. What I get excited about is
seeing that damned Bouy in the middle where the two channels intersect in
the fog....you know....so I don't run over it and scrape up the gelcoat,
looking like a complete fool...(c; I always thought it unfortunate
someone doesn't make a sector scanning radar to mount on the bow that can
see only 1000 yards in an arc of 120 degrees, straight ahead. It would
have a very short pulse length, which is the other limit on how close the
radar can see the target from the boat. Radar travels at 300 meters per
microsecond. During the time the transmitter is transmitting, the
receiver is shorted out to protect its sensitive receiver
electronics...on every pulse, we hope. If the transmitter is on for 1
microsecond, any target's echo less than 150 meters away (out, reflect,
come back), comes back while the transmitter is on and the receiver is
off. So, no target is received. If the pulse width (transmitter on
time) is .1 microseconds, the distance is 15 meters and way too late to
turn...(c; Modern radars adjust their pulse widths and the number of
pulses per second (repetition rate) as you reduce range, because close
targets don't need so much RF power so wide to see them with the display
set so close. (Your sonar also works this way, but at sound speed in
water, lots slower.) The pulse width also determines how much resolution
your radar sees on targets close together in line with your signal. If
two boats are in line with your sight and 100 meters apart, the wide
pulsewidth shows one thick target. Narrow pulsewidths resolve them as
two targets because the signal that bounces back shuts down from the
close target before the signal from the outer target starts, leaving a
gap in signals, and a resulting gap in display blip.

In a slow sailboat, compared to something going 30+ knots draining the
tanks, I think 25 ft up is a good compromise between range out 6 miles
and range close in on that nasty bouy with the gelcoat cutting
barnacles....(shudder)

Of course, once the proper short transmitter is beaconing all the bouys
and obstructions, and the boats are forced to either beacon their AIS
data or stay at the dock, all this becomes moot....Watch this:
http://www.aisliverpool.org.uk/currentmap.php?map=48
Just move your mouse pointer over any ship in the Irish Sea and look at
what AIS is all about. Radar's obsolete...It's time America joined the
21st Century. If you can afford to go to sea, you can afford an AIS
transponder, which will get cheaper and cheaper if the market were
expanded rapidly.



Larry
3rd mate engineering, S/V "Lionheart"....
A boat can never have too many electronic gadgets....(c;

radar questions
 

One point Larry missed: That big array will focus the transmit power available.
So 4 KW with a small array will get the same range as 2KW with a small array.

Right Larry?

Also: even in typical power boat, how often do you care about traffic more than
a mile a or two away? I'd rather have really good results close in and NOTHING
more than a couple of miles away (I do boat in an area where there's very little BIG
boat traffic. Maybe a dozen cruise ships a year, and they come in after my boat's
on the trailer on the way home, and leave while I'm diving.


"Larry" wrote in message ...
"luc" wrote in news:1162924151.581326.150280
@m7g2000cwm.googlegroups.com:

A few questions. Is there another small radar that is good?

You get what you pay for. It's that simple. More power has more
range..IF it's up high. It can't see over the horizon. Its horizon is
the same as yours on a clear day. The difference is it can see through
fog and in the dark. The stronger its transmitter, the stronger its
returns from the targets and the strong transmitter making stronger
returns can see more at the same distance in bad weather. Read that,
smaller targets, too.

Is the
quality of the radar directly related to the size of the radome?

The larger the antenna array, the narrower its beamwidth (horizontally).
The narrower the beamwidth, the better it is at resolving the target's
position. A wider beam makes an arc of a target on the display, from
angle it starts seeing the target to the angle it loses the signal from
the target. A bigger antenna, with a much narrower beamwidth, cause a
smaller target on the display, raising the accuracy of the bearing of the
target. The narrower beamwidth also turns one wide target on Radar A
into 4 distinct targets from the big antenna on Radar B. B simply
resolves the targets as individuals because the beam is narrow enough to
stop receiving one target before starting to receive the next as it
sweeps by. So, instead of a blob, you get 4 dots showing better
positions. It's all about horizontal beamwidth. We want narrow
horizontal beamwidth but WIDE vertical beamwidth. If the vertical
beamwidth is too narrow, when your boat heels over or pitches and rolls,
none of the beam that's so narrow lights up the target, so no signal
returns and he doesn't show up on the screen. These tilting mounts sound
nice and do, slightly, improve target painting, but the radars' vertical
beamwidth is so wide, by design, you'll see the target out the beams
heeled over 35 degrees, anyways. The tilting mount centers the RANGE of
the allowable vertical tilt it will tolerate.

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?


That's easy. Climb up to where you think you're going to put the radar
while drifting in the harbor. How far can you see? That's how far the
radar can see. It sees targets over the horizon that are tall enough to
come up above the horizon, like tall TV towers, big buildings, water
towers, lighthouses. If you can't see it, the radar can't, either, no
matter what its antenna size and power. It's not magic or clairvoyant.

There's another problem. As you raise up the antenna higher and higher
to see that ship 32 miles away, the vertical beamwidth ends at a higher
and higher altitude, farther and farther from the boat CLOSE IN. From
the top of the mast, that big bouy you're about to run into disappears
from the screen in the fog because the bottom of the radome is a radar
shield to keep from cooking the kids' brains on deck. So, the higher the
radar is located, the further out from the boat the close in targets
disappear because you're shooting the signal right over the top of them.
In a sailboat, I don't get too excited seeing a target over 6 miles away
unless it's doing over 100 miles per hour. What I get excited about is
seeing that damned Bouy in the middle where the two channels intersect in
the fog....you know....so I don't run over it and scrape up the gelcoat,
looking like a complete fool...(c; I always thought it unfortunate
someone doesn't make a sector scanning radar to mount on the bow that can
see only 1000 yards in an arc of 120 degrees, straight ahead. It would
have a very short pulse length, which is the other limit on how close the
radar can see the target from the boat. Radar travels at 300 meters per
microsecond. During the time the transmitter is transmitting, the
receiver is shorted out to protect its sensitive receiver
electronics...on every pulse, we hope. If the transmitter is on for 1
microsecond, any target's echo less than 150 meters away (out, reflect,
come back), comes back while the transmitter is on and the receiver is
off. So, no target is received. If the pulse width (transmitter on
time) is .1 microseconds, the distance is 15 meters and way too late to
turn...(c; Modern radars adjust their pulse widths and the number of
pulses per second (repetition rate) as you reduce range, because close
targets don't need so much RF power so wide to see them with the display
set so close. (Your sonar also works this way, but at sound speed in
water, lots slower.) The pulse width also determines how much resolution
your radar sees on targets close together in line with your signal. If
two boats are in line with your sight and 100 meters apart, the wide
pulsewidth shows one thick target. Narrow pulsewidths resolve them as
two targets because the signal that bounces back shuts down from the
close target before the signal from the outer target starts, leaving a
gap in signals, and a resulting gap in display blip.

In a slow sailboat, compared to something going 30+ knots draining the
tanks, I think 25 ft up is a good compromise between range out 6 miles
and range close in on that nasty bouy with the gelcoat cutting
barnacles....(shudder)

Of course, once the proper short transmitter is beaconing all the bouys
and obstructions, and the boats are forced to either beacon their AIS
data or stay at the dock, all this becomes moot....Watch this:
http://www.aisliverpool.org.uk/currentmap.php?map=48
Just move your mouse pointer over any ship in the Irish Sea and look at
what AIS is all about. Radar's obsolete...It's time America joined the
21st Century. If you can afford to go to sea, you can afford an AIS
transponder, which will get cheaper and cheaper if the market were
expanded rapidly.



Larry
3rd mate engineering, S/V "Lionheart"....
A boat can never have too many electronic gadgets....(c;

radar questions
 

Luc,
The Furuno radars are as good, if not better than all the others, but the
point you are missing is performance. You have stated that you need a radar.
Here there are two things that outweigh all the others. The first is array
size. Target descrimination is everything. The small scanners spread their
power across a beam width of 3 to 4 degrees. A 6 ft open array has a beam
width of 1.2 to 1.8 degrees. This effectively doubles the power delivered to
a target. The weight difference is only 10 to 15 lbs. Since range is NOT as
important as close in targets mounting the radar aft outside of the sail
plan, extra size and weight is of no consequence. Add to that more power and
you have a radar that truly discriminates one target type from another. So,
the rule is bigger and more powerful is better. If you have the electric
power and the room , use it.
Steve

"luc" wrote in message
ups.com...
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

radar questions
 

Note: My earlier recommendations (4kw, stern mounting, etc.), take into
account you have a racing boat, are around other racing boats, and if
your are really compelled to add a radar at all, focus on features that
will make it worth doing and features that are more important in
minimizing the impact on racing ( than the weight of the radome ) in
planning your total purchase and installation, rather than for example
range. Even if you could save 5 pounds off the typical 18 lb weight of
a radome, it wouldn't necessarily improve performance since the weight
of the entire system (assuming no additional batteries are needed) will
be north of 50 lbs, and the 5 lbs especially won't matter as your deck
crew is dealing with a halyard or sail getting caught in it even for a
few seconds.

radar questions
 

Also ... in case you started doing the math of how much power you will
need and possible upgrades of your electrical system, and are
attempting to convert that 2kw or 4kw into amp hour draw on your
battery, hold up.

Also ... note that 4kw radomes such as Raymarine's only use 38 watts of
battery power while active, and 10 watts in standby. The transmitter is
in the "off" cycle of each pulse, for most of each second. Since all
the electronics in the radome are on all the entire time, the
chartplotter of course is on all the time, the total power consumption
between a 2kw and 4kw system is negligable.

radar questions
 

Also ... in case you started doing the math of how much power you will
need and possible upgrades of your electrical system, and are
attempting to convert that 2kw or 4kw into amp hour draw on your
battery, hold up.

A 4kw radomes such as Raymarine's only uses 38 watts of battery power
while active, and 10 watts in standby (per the documentation). That is
a lot less than the 4000 watts you might be thinking 4kw implies. The
transmitter is in the "off" cycle of each pulse, for most of each
second, giving the electronics some type to store up those 38 watts and
release them in a powerful pulse. Since all the electronics in the
radome are on all the entire time, the chartplotter of course is on all
the time, the total power consumption between a 2kw and 4kw system is
negligable.

Dan

radar questions
 

I've got a Furuno 1623 and the beamwidth is noticeable compared to the
high quality navigation radars I have been used in large ships.
Howeevr, it has proved to be pretty good - picking up small contacts
close in and dealing with clutter effectively.

radar questions
 

First, I'd say that the Cat's skipper probably said that he saw it as
junk because he was used to something better. I've seen the world
through a USN 3D radar and now I think that all other radars are junk,
this is'nt really true but it is the way that I see it. My boat
doesn't have a radar, it did but the previous owner tore it out, and if
I get one it will be El Cheapo Dexulo whose sole purpose is as a
collision avoidance alarm. Which brings me to;

Second, for what purpose do you want it, collision avoidance or a
navigational aid?
If it's just an alarm, go cheap, mount low, but get the tiltable mount
and as another fellow mentioned, specify to your salesman short range!
If it is for a nav aid, spend as much as you can, mount as high as you
can. Otherwise, you will be calling your own radar a piece of junk,
after you've seen someone else's fancier radar [did you know that with
a REALLY good radar, you can actually see {oops, sorry, gotta censor
that, it's classified...}]

:)

Thirdly, you could do what I do. Heave to, throw up two red lights,
set the auto fog horn to once a minute and go to bed.

Lastly, to make a truly informed decision that you won't regret, you
must See the various brands and models of radars, in the various
configurations and talk to the operators about what they do and Don't
like about it. And that's gonna take quite some time! When you run
into someone who says 'this is the best darned radar I ever had!' and
you ask him why And you understand his reasoning, then buy that radar
and mount it in that configuration.
You've gotten several good bits of advise here, but notice that no one
has confirmed or denied whether the 1623 is better or worse than the
1715. Of course they couldn't because you didn't state the purpose.

Well, good luck. And remember that I can fix a radar but I can't sell
them.
O, and ask that Cat Skipper [and everyone else] what radar Did he like,
and Why.

tom
SS_Kanwara
=-==





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

radar questions
 

Tlindy,

I strongly disagree, you are overestimating the lowest end of the radar
offerings. You cannot just set a guard zone and have it detect a
collision. There is no ARPA feature, and the MARPA feature requires a
lot of opearator assistance, as well as an extra $900 heading sensor to
help it better track targets.

At the lowest end they are much more difficult to be used for collision
avoidance with boats or land, paying more money quickly lessens the
amount of time and expertise needed to operating them, but even then, a
higher-end recreational radar probably requires more understanding to
operate then any other device on a sailboat, and a significant
concentration to operate. For example, on the lowest end radar most
other sailboats don't appear on the screen unless you play with the
gain with then requires even more concentration and experience, and
features like overlaying a chart with bouys and depths can further ease
the work load on a radar operator who is also piloting.

I don't believe the average person should get anything less than an
integrated chartplotter with maps a good 4kw radar, a lot of reading,
at least 4 hours of on the water training, and resolve to use the radar
in good conditions twice a month to keep up skills. Otherwise, all you
might be buying is a radar assisted collision.

Dan

p.s. I use a Raymarine E-80 chartplotter and 2kw radome, and have it
mounted the minimum distance up the mast I could arrange so that I have
good close in coverage, and placed it on a self leveling mount so I
don't have blind spots when the boat heals. I think the beamwidth is
good, but wish I got the extra power so I can see other sailboats,
especially the ones that are pointed right at me and have a very low
return. Pushing up the gain a bit I can see them, but then I get false
returns also. I also added a heading sensor to improve the MARPA
performance, which also improved my autopilot performance.






tlindly wrote:
First, I'd say that the Cat's skipper probably said that he saw it as
junk because he was used to something better. I've seen the world
through a USN 3D radar and now I think that all other radars are junk,
this is'nt really true but it is the way that I see it. My boat
doesn't have a radar, it did but the previous owner tore it out, and if
I get one it will be El Cheapo Dexulo whose sole purpose is as a
collision avoidance alarm. Which brings me to;

Second, for what purpose do you want it, collision avoidance or a
navigational aid?
If it's just an alarm, go cheap, mount low, but get the tiltable mount
and as another fellow mentioned, specify to your salesman short range!
If it is for a nav aid, spend as much as you can, mount as high as you
can. Otherwise, you will be calling your own radar a piece of junk,
after you've seen someone else's fancier radar [did you know that with
a REALLY good radar, you can actually see {oops, sorry, gotta censor
that, it's classified...}]

:)

Thirdly, you could do what I do. Heave to, throw up two red lights,
set the auto fog horn to once a minute and go to bed.

Lastly, to make a truly informed decision that you won't regret, you
must See the various brands and models of radars, in the various
configurations and talk to the operators about what they do and Don't
like about it. And that's gonna take quite some time! When you run
into someone who says 'this is the best darned radar I ever had!' and
you ask him why And you understand his reasoning, then buy that radar
and mount it in that configuration.
You've gotten several good bits of advise here, but notice that no one
has confirmed or denied whether the 1623 is better or worse than the
1715. Of course they couldn't because you didn't state the purpose.

Well, good luck. And remember that I can fix a radar but I can't sell
them.
O, and ask that Cat Skipper [and everyone else] what radar Did he like,
and Why.

tom
SS_Kanwara
=-==





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

radar questions
 

"b393capt" wrote in
ups.com:

I use a Raymarine E-80 chartplotter and 2kw radome

Look inside your 2KW radome and see if it's all wet in there corroding up
the pot metal it's made of. We'll look at ours in spring to see if it
needs its 4th replacement....(sigh).

It doesn't really "leak", as in rainwater pouring in. It breathes. It
breathes in wet air after dusk which condenses all night on the pot metal
parts, then burns off into 100% humidity swamp all day, expelling some hot
air so it will be able to breathe in the next load of wet air, tonight.
The pot metal turns into a white powder conductive salt that rains down on
the circuit boards that SHOULD have been in a sealed container, but that
would have required we use sealed plugs, not pins sticking off the printed
circuit board for a connector. So they left it open. Not only is it all
corroded up on the outside....but inside, too, where the data and receiver
boards are located.

Notice how the magnetron's soft iron core is all rusted....

Larry
--
Halloween candy left over.....
Is there a downside?

radar questions
 

4 units. Wow. What's the average life ?

Larry wrote:
"b393capt" wrote in
ups.com:

I use a Raymarine E-80 chartplotter and 2kw radome

Look inside your 2KW radome and see if it's all wet in there corroding up
the pot metal it's made of. We'll look at ours in spring to see if it
needs its 4th replacement....(sigh).

It doesn't really "leak", as in rainwater pouring in. It breathes. It
breathes in wet air after dusk which condenses all night on the pot metal
parts, then burns off into 100% humidity swamp all day, expelling some hot
air so it will be able to breathe in the next load of wet air, tonight.
The pot metal turns into a white powder conductive salt that rains down on
the circuit boards that SHOULD have been in a sealed container, but that
would have required we use sealed plugs, not pins sticking off the printed
circuit board for a connector. So they left it open. Not only is it all
corroded up on the outside....but inside, too, where the data and receiver
boards are located.

Notice how the magnetron's soft iron core is all rusted....

Larry
--
Halloween candy left over.....
Is there a downside?

radar questions
 

"b393capt" wrote in
oups.com:

4 units. Wow. What's the average life ?



A year or two. So far, Raymarine has been replacing them, as they did the
Raystar 120. Can't complain about the tech support...but wouldn't it be
better to fix the design? I notice the new radars on the dock are now in a
different case, but still have the drain tit sticking out the bottom,
instead of a pressurizing, SEALED radome. I don't understand it...??

Sitting in the muck at the bottom of the mizzenmast the 2KW radome is
mounted on is an Icom AT-140 HF antenna tuner for the insulated backstay on
the main. Its plastic box is SEALED with many screws and a rubber grommet.
It has been awash in water since we got it, seawater spray offshore. The
inside of it is as shiny new as it came to us. Why can't radar
manufacturers use a SEALED radome with proper SEALED stuffing tubes that
doesn't breathe in the muck and rot the guts? How silly....like the stupid
push-to-open wire clamps the control cable on the radome has inside it,
also in the muck....(sigh)

I'm not asking for proper dry nitrogen pressurization....just something
that SEALS and doesn't BREATHE! Changing radomes sucks!

Larry
--
Halloween candy left over.....
Is there a downside?

radar questions
 

Charlie Morgan wrote in
:

No corrosion problems at all with my Furuno. You'll notice that the
vast majority of commercial fishing boats have Furuno RADAR. Corrosion
problems with other brands may be the reason!



How is that one sealed up? Is there any drain in it? I couldn't believe
there was a hole in the bottom of the Raymarine when I looked at it.

Larry
--
Halloween candy left over.....
Is there a downside?

radar questions
 

Charlie Morgan wrote in
:

Seems to be very well sealed. The dome and base have a tight fitting
rubber gasket that wraps around the edges of both pieces. The cable
goes through a rubber "compression" seal as well. No need for a drain.
I haven't tried it, but it might even surivive submersion, at least
for a while.


Yo! Raymarine! You readin' dis, bo?!

Thanks. Just wanted to see if they were watchin'.

Larry
--
Halloween candy left over.....
Is there a downside?

radar questions
 

Luc,

You out there ? Did this help ??

radar questions
 

Thanks for the information, I've learned something here. My principal
concern is collision avoidance, but it occurred to me that it could
also be used tactically while racing.

I know most of you are likely cruisers, and I am too, which is why I
need to use a radar for collision avoidance. Last summer, I had to
sail my boat from San Diego to Moss Landing, and we did most of it at
night, and in fog, without radar. Nuts? yeah, seemed like it at the
time.

A couple of weeks ago, I took a friend's boat to San Diego from Moss
Landing, and it had a new Raymarine radar and chartplotter. It worked
great, though my experience with radar is limited, by the time we got
to SD, I had a pretty good idea of the menus, and how the thing worked.


Racing is pretty nutty at times, and weight and weight aloft is taken
quite seriously. But not at the expense of safety. Many race boats
have no radar, but someday, I will.

thanks again folks!

radar questions
 

"luc" wrote in news:1163465166.495131.5330
@e3g2000cwe.googlegroups.com:

A couple of weeks ago, I took a friend's boat to San Diego from Moss
Landing, and it had a new Raymarine radar and chartplotter. It worked
great, though my experience with radar is limited, by the time we got
to SD, I had a pretty good idea of the menus, and how the thing worked.



I know SD is a very busy place, visavis shipping. Another good idea,
even if you never consider a full transponder so YOU show up, is the new
AIS (Automatic Information System)receivers. In that fog, you would have
no trouble at all spotting all the AIS-equipped shipping, those monster
targets that insist on moving around, unlike a rock or bouy you can stay
away from. AIS lets you watch, and avoid the beasts that can just ruin
your cruise, with ease. There are several new AIS to NMEA receivers that
will plot the AIS targets right on your chartplotter, probably with
nothing more than a plotter firmware upgrade. If you'd like to see what
it can see and look at the plethora of data it can provide you, the best
place is the Irish Sea. Go to Liverpool's great:
http://www.aisliverpool.org.uk/index.php
Take a long look around. The site is live, now in realtime. Just move
your mouse over a target on any map, chart or satellite photo and you'll
read all about him. Click on him and it brings up each ship's personal
webpage with near-realtime photos, taken automatically the last time he
passed one of the AISlive cameras in Liverpool's harbor. It's an amazing
software.

Someday, America may even have similar software running and shore-based,
fixed obstacle AIS transmitters that will cause everyone's AIS to also
show the fixed targets we still have to look for on radar....(sigh)



Larry
--
My calendar must be wrong....
In all the stores, it's ALREADY Christmas!

radar questions
 

Charlie Morgan wrote in news:bbnjl2t0gr9j3us1eb81f8rb0ifceg1tpk@
4ax.com:

US Military ships do not, and will not, have AIS.

CWM



Very soon, military ships will also be totally invisible on your little
radar, too! They already have a few....

As with the stealth aircraft, THEY are to watch out for YOU....

Larry
--
My calendar must be wrong....
In all the stores, it's ALREADY Christmas!

radar questions
 

"Larry" wrote in message
...
Charlie Morgan wrote in news:bbnjl2t0gr9j3us1eb81f8rb0ifceg1tpk@
4ax.com:

US Military ships do not, and will not, have AIS.

CWM



Very soon, military ships will also be totally invisible on your little
radar, too! They already have a few....

As with the stealth aircraft, THEY are to watch out for YOU....

Larry


I suppose we could equip all the logs, deadheads and kayaks with AIS, but
just here in the Puget Sound, it would be fairly expensive. Radar rules!
(assuming 3' or better scanner, and scanner mounted fairly low on the mast)
Old Chief Lynn

radar questions
 

"Lynn Coffelt" wrote in
:

I suppose we could equip all the logs, deadheads and kayaks with AIS,
but just here in the Puget Sound, it would be fairly expensive. Radar
rules! (assuming 3' or better scanner, and scanner mounted fairly low
on the mast) Old Chief Lynn


Your radar can see logs and kayaks?! I want one of those! It's gotta be
magic. How many gigawatts does that take to get a return off a plastic
kayak?

I guess you're assuming the guy in the kayak has a metal Coleman stove in
there, too...(c;

We border on the absurd....which is why they'll make them mandatory over X
ft long....and all that go to sea.


Larry
--
My calendar must be wrong....
In all the stores, it's ALREADY Christmas!

radar questions
 

Your radar can see logs and kayaks?! I want one of those! It's gotta be
magic. How many gigawatts does that take to get a return off a plastic
kayak?

I guess you're assuming the guy in the kayak has a metal Coleman stove in
there, too...(c;

We border on the absurd....which is why they'll make them mandatory over X
ft long....and all that go to sea.


Larry

Gigawatts? Woohoo..... we don't want to burn the hair off the poor
guy's legs, just see a wee echo from the fillings in his teeth! Seriously, a
3kw with a weak maggie should be able to see seagulls and ducks on the water
(when the water is flat, of course). I don't have a radar at all, but have
worked on thousands of them. Well, OK, maybe only hundreds. When the short
range, X band radar scanner is fairly close to the water, as opposed to the
mistake of mounting as high as possible, painting small wet objects improves
greatly. I'm sure many are familiar with the impossible sea clutter one
encounters looking down at a high angle from high up on the ship. Painting
any targets at all is a challenge. Oh, yes, it sees those mountain ranges 30
miles away alright, but we aren't apt to hit them soon.
Is AIS used on relatively unmovable objects such as rocks and small
islands? There are quite a few radar beacons in use, but some radar receiver
interference rejection schemes wipe them off the screen too. (I almost said
"scope", nearly revealing my age!)
Christmas? I thought we now used politically correct names?
Old Chief Lynn

radar questions
 

Your radar can see logs and kayaks?! I want one of those! It's gotta be
magic. How many gigawatts does that take to get a return off a plastic
kayak?

WTF? My 4kw Raymarine setup sees kayaks with no trouble at all. That and
when there water's smooth it'll even pickup the occasional bird and, rarely,
a crab pot float.

radar questions
 

I have worked on 25kw units for aircraft (California fish and game) that can
see seagulls at 3/4 mile and measure fishing nets floating in the water.
This is how they busted the commercial fishermen that put out more net than
they were allowed.
The Magic here was in the digital processing to filter out the noise.
You can ether use lots of power or lots of processing power, these days the
processing power is cheaper and safer.

radar questions
 

"Lynn Coffelt" wrote in
:

Is AIS used on relatively unmovable objects such as rocks and
small
islands? There are quite a few radar beacons in use, but some radar
receiver interference rejection schemes wipe them off the screen too.
(I almost said "scope", nearly revealing my age!)


Radar requires the target to be REFLECTIVE, not absorptive or transparent
to RF. That's what that funny ball hanging from the already reflective
metal mast is, it makes you more reflective. A wet, plastic boat with an
RF absorptive human isn't going to cut it. The seawater returns more
than that....

As to your AIS barb...YES! But, your concept of AIS being located on a
bouy is all wet, so to speak. AIS has no bearing on it being mounted ON
the object it reports. That transmitter can be anywhere, as long as it
is in VHF range of the receivers. Fixed objects and Notice to Mariners
objects only need one, central transmitter high enough to cover the
entire area. This transmitter broadcasts the data of all these objects
every X minutes, to the delight of every AIS-equipped boat in range.
That range can be substantial. The sooner this equipment is installed
and the CG forced, kicking and screaming, to maintain its database with
all the latest data, the better!

For instance, a report comes in from the "Lady Disaster" that there is a
new object gone aground on "Monster Bank" at X lat/Y long, and represents
a hazard to navigation. The broadcast noone listens to goes out on
Channel 22 and falls on deaf ears. Admit it, you don't listen to it when
you're out, do you? I thought not. Who the hell's got time to plot
these broadcasts? However, the duty watch at the CG base also enters the
new object into the AIS database the fixed area transmitter draws its
data from. The very next transmission cycle, the new object shows up on
ever AIS display/chartplotter within 50 miles of the TV tower the
transmitter is located on. You can easily see the new obstruction. It's
right there on your display at the helm.

The bouy tender has arrived to assess the situation at "Jim Island" found
to be shifting into the channel. Bouy 4C is nearly sitting on dry land
because of the current shift and they lift it out and service its
batteries, replacing a bad bulb in the bulb rack in the head. They
replace the bouy in a new position further out in the channel than it was
to mark a safe distance from the new beach Jim Island is building for the
kids to play on next spring. Job completed, the duty radioman pops up
his AIS update screen on the ship's computer and logs onto the local AIS
database, right from Jim Island. He pops up Bouy 4C's record and enters
the new lat/long of its new position, making a note on its comment
section of the building beach to warn AIS-equipped boats to be wary as it
is still building. INSTANTLY, on the next transmission 86 seconds later,
every AIS-equipped boat notices 4C move to its new location and can read
that comment if they click up the bouy on their AIS-enabled chartplotter.

How long would it currently take to note 4C has moved 300 yards into the
channel, or a new warning come out from any authority now in use? Weeks?
Months? 12 days after the damned bouy has to be moved again?!

The sooner the better. There is NO TRANSMITTER ON ANY BOUY on an AIS
system! Totally unnecessary. There needs to be a central database and
high transmitter to cover the whole area on the AIS system... AIS is
about DATA, not direction finding.

Larry
--
Wow. Halloween candy has gotten cheap, lately!

radar questions
 

In article ,
"Lynn Coffelt" wrote:

Your radar can see logs and kayaks?! I want one of those! It's gotta be
magic. How many gigawatts does that take to get a return off a plastic
kayak?

I guess you're assuming the guy in the kayak has a metal Coleman stove in
there, too...(c;

We border on the absurd....which is why they'll make them mandatory over X
ft long....and all that go to sea.


Larry

Gigawatts? Woohoo..... we don't want to burn the hair off the poor
guy's legs, just see a wee echo from the fillings in his teeth! Seriously, a
3kw with a weak maggie should be able to see seagulls and ducks on the water
(when the water is flat, of course). I don't have a radar at all, but have
worked on thousands of them. Well, OK, maybe only hundreds. When the short
range, X band radar scanner is fairly close to the water, as opposed to the
mistake of mounting as high as possible, painting small wet objects improves
greatly. I'm sure many are familiar with the impossible sea clutter one
encounters looking down at a high angle from high up on the ship. Painting
any targets at all is a challenge. Oh, yes, it sees those mountain ranges 30
miles away alright, but we aren't apt to hit them soon.
Is AIS used on relatively unmovable objects such as rocks and small
islands? There are quite a few radar beacons in use, but some radar receiver
interference rejection schemes wipe them off the screen too. (I almost said
"scope", nearly revealing my age!)
Christmas? I thought we now used politically correct names?
Old Chief Lynn



Ok I feel a "Story" coming on..... Years ago when I worked for Northern
Radio Company in Seattle, WA as a Field Tech, they picked up the Furuno
Radar Line, and sold the first KRA124 in the country. I was the Install
Tech, and we put it on a "Big Time Pleasure Cruiser" floating in Lake
Union. Antenna unit was 9Kw (2J42 Magnitron) with a 3 Ft Slotline,
Endfeed Antenna, and a Linear IF Strip. When we were out on Sea Trials,
setting the Heading Flash, and Tx Pulse Delay, the skipper noticed a
bunch of target returns about 1.25 miles off the bow. He looked out with
some Binocs and couldn't see anything that looked like a Radar Reflector,
so he asks what those targets were. I took the binocs, and scanned the
area, where the targets were on the scope and there were a small flock
of seagulls, sitting on the water. "Seagulls" says I. He said "BS" and
I looked again, and said "Wana Bet?" He says "Sure, how much can you
afford?" "Lunch at the Latitude 48 would be nice", says I, and we had a
bet. Just then, a SuperCub on floats was taxiing out from Kutzner Air
Service and headed for the Seagulls, so I told him to watch the scope,
and as soon as the floatplane got close to the birds, they would fly
off, and all the targets would be gone. Sure enough, the SeaGulls flew
off, the floatplane took-off, but the Skipper says "There is still a
target there". I look in the scope and sure enough there is still one
target in that spot. So I says, "There is something there, but it is to
small to see at this distance." He says, "BS, but we will go over there
and take a look". So we cruise on over and sure enough, there is a
styrofoam coffee cup floating in that location. He has the Deckhand fish
it out of the water and we head on back to the dock. Sure enough, "No
More Targets in that part of the lake. I got my lunch, the Skipper got a
Great Radar, and we both have a Great Story to tell for the rest of time.

Nothing like 9Kw of XBand RF with a Good Slotline Antenna to pick up
small stuff on flat water. These 4Kw T/R Pans just don't have the
poop, even with the new LogRythemic Receivers, and MMIC's for Frontends.
All it takes is Power, and a decent antenna, which are in short supply
on most non-commercial and Pleasure Craft type Radars these days. That
same 9Kw T/R with a 6Ft antenna was the basis of the KRA-448 Furuno
Radar that was a 48 Mile that could see out to 72 miles if you pushed
it. Mountains that are 6000 ft tall show up real well, at 72 miles.

Bruce in alaska
--
add a 2 before @

radar questions
 

Ok I feel a "Story" coming on..... Years ago when I worked for Northern
Radio Company in Seattle, WA as a Field Tech, they picked up the Furuno
Radar Line, and sold the first KRA124 in the country. I was the Install
Tech, and we put it on a "Big Time Pleasure Cruiser" floating in Lake
Union. Antenna unit was 9Kw (2J42 Magnitron) with a 3 Ft Slotline,
Endfeed Antenna, and a Linear IF Strip. When we were out on Sea Trials,
setting the Heading Flash, and Tx Pulse Delay, the skipper noticed a
bunch of target returns about 1.25 miles off the bow. He looked out with
some Binocs and couldn't see anything that looked like a Radar Reflector,
so he asks what those targets were. I took the binocs, and scanned the
area, where the targets were on the scope and there were a small flock
of seagulls, sitting on the water. "Seagulls" says I. He said "BS" and
I looked again, and said "Wana Bet?" He says "Sure, how much can you
afford?" "Lunch at the Latitude 48 would be nice", says I, and we had a
bet. Just then, a SuperCub on floats was taxiing out from Kutzner Air
Service and headed for the Seagulls, so I told him to watch the scope,
and as soon as the floatplane got close to the birds, they would fly
off, and all the targets would be gone. Sure enough, the SeaGulls flew
off, the floatplane took-off, but the Skipper says "There is still a
target there". I look in the scope and sure enough there is still one
target in that spot. So I says, "There is something there, but it is to
small to see at this distance." He says, "BS, but we will go over there
and take a look". So we cruise on over and sure enough, there is a
styrofoam coffee cup floating in that location. He has the Deckhand fish
it out of the water and we head on back to the dock. Sure enough, "No
More Targets in that part of the lake. I got my lunch, the Skipper got a
Great Radar, and we both have a Great Story to tell for the rest of time.

Nothing like 9Kw of XBand RF with a Good Slotline Antenna to pick up
small stuff on flat water. These 4Kw T/R Pans just don't have the
poop, even with the new LogRythemic Receivers, and MMIC's for Frontends.
All it takes is Power, and a decent antenna, which are in short supply
on most non-commercial and Pleasure Craft type Radars these days. That
same 9Kw T/R with a 6Ft antenna was the basis of the KRA-448 Furuno
Radar that was a 48 Mile that could see out to 72 miles if you pushed
it. Mountains that are 6000 ft tall show up real well, at 72 miles.

Bruce in alaska

I just knew that I would be "topped" if Bruce ever came onto this
thread. I think I might have worked on that first KRA124 of yours. There
weren't too many of them around here. The one that gave me more grief than
any I ever worked on was one on a well-to-do fisherman's yacht/halibut boat.
There were some strange diodes in the klystron tune regulated voltage source
that were no longer available (this in about maybe 1978). Dumb thing would
drift out of front panel tuning range periodically. Could bring it right
back with chassis pot, of course, but owner frowned on that and I never did
get paid! Don't blame him a bit.
We (Whatcom Marine/ Nordic Marine/ Anacortes Marine) took the
Washington State Ferries contract for a few years, and there were a few
KRA-448's that Northern had installed earlier. Super seagull radar with the
6ft scanner, but with the shorter scanner and all that power, it made nearby
ships real scary! Sort of wrapped around you! I think it was Northern that
put the 72 mile switch position modification on a couple. Only long targets
around here were from out in Rosario Straits looking north up into Canada.
Saw stuff to 62 or 63 miles if there wasn't any rain in the way.
AIS sure sounds great, but there is no substitute for radar (not
talking about the 3ft or less PCB antenna types). Some of the newer video
processing that cleans up sea clutter just has to be seen to be believed.
But I digress. Again.
Old Chief Lynn

radar questions
 

In article ,
"Lynn Coffelt" wrote:

There were some strange diodes in the klystron tune regulated voltage source
that were no longer available (this in about maybe 1978). Dumb thing would
drift out of front panel tuning range periodically. Could bring it right
back with chassis pot, of course, but owner frowned on that and I never did
get paid! Don't blame him a bit.

The KRA124/248/448 didn't have a Klystron for an LO, but was the first
of the Second Generation Radars, and used an XBand Gun Diode Osc. As
I recall Furuno last used a 2K25 Klystron in the KRA 121 Series Radars
which was before Northen picked up the Furuno Dealership. Don
Hollingsworth Sr. at G & L Marine was the KRA-121 expert and has always
been the "Go To Guy" for Marine Radar Technical Information, even when
he was the Raytheon Marine Tech (Ray 1500/1700/1900) for the NorthWest,
and worked for U.G. Allen.

Man that does date me, in the North Pacific Marine Electronic Community.

Bruce in alaska
--
add a 2 before @

radar questions
 

Dunno about the model, but I was hanging out in the wheel house of one of the
Monterey dive boats a few years ago while we were coming back from a couple
of dives off Big Sur. It's grey day, but the marine layer was up off the water and
visibility was maybe four miles. At about Cypress Pt. the radar starts showing a
BIG target dead ahead. a couple of miles.

Now, A) we don't get big targets in Monterey very often, and esp not in water that
shallow, and B) we can't see any big targets visually. A couple of small boats, and the
Pt. Pinos buoy a couple of miles out, but nothing near that big. When the
range gets down to about a half mile, Capt. Phil starts looking kinda nervous. Then
the marine layer lifts a bit, and: Goodyear Blimp. ;-)

"Bruce in Alaska" wrote in message ...
In article ,
"Lynn Coffelt" wrote:

There were some strange diodes in the klystron tune regulated voltage source
that were no longer available (this in about maybe 1978). Dumb thing would
drift out of front panel tuning range periodically. Could bring it right
back with chassis pot, of course, but owner frowned on that and I never did
get paid! Don't blame him a bit.

The KRA124/248/448 didn't have a Klystron for an LO, but was the first
of the Second Generation Radars, and used an XBand Gun Diode Osc. As
I recall Furuno last used a 2K25 Klystron in the KRA 121 Series Radars
which was before Northen picked up the Furuno Dealership. Don
Hollingsworth Sr. at G & L Marine was the KRA-121 expert and has always
been the "Go To Guy" for Marine Radar Technical Information, even when
he was the Raytheon Marine Tech (Ray 1500/1700/1900) for the NorthWest,
and worked for U.G. Allen.

Man that does date me, in the North Pacific Marine Electronic Community.

Bruce in alaska
--
add a 2 before @

radar questions
 

In article ,
"Chuck Tribolet" wrote:

Dunno about the model, but I was hanging out in the wheel house of one of the
Monterey dive boats a few years ago while we were coming back from a couple
of dives off Big Sur. It's grey day, but the marine layer was up off the
water and
visibility was maybe four miles. At about Cypress Pt. the radar starts
showing a
BIG target dead ahead. a couple of miles.

Now, A) we don't get big targets in Monterey very often, and esp not in water
that
shallow, and B) we can't see any big targets visually. A couple of small
boats, and the
Pt. Pinos buoy a couple of miles out, but nothing near that big. When the
range gets down to about a half mile, Capt. Phil starts looking kinda
nervous. Then
the marine layer lifts a bit, and: Goodyear Blimp. ;-)


I always liked to see what skippers would do when they saw a target on
their radar, that was moving at 100Kts directly at them. FloatPlanes
flying at 500Ft, look really strange on Marine Radars....

Bruce in alaska
--
add a 2 before @

radar questions
 

"Bruce in Alaska" wrote in message
...
In article ,
"Lynn Coffelt" wrote:

There were some strange diodes in the klystron tune regulated voltage
source
that were no longer available (this in about maybe 1978). Dumb thing
would
drift out of front panel tuning range periodically. Could bring it right
back with chassis pot, of course, but owner frowned on that and I never
did
get paid! Don't blame him a bit.

The KRA124/248/448 didn't have a Klystron for an LO, but was the first
of the Second Generation Radars, and used an XBand Gun Diode Osc. As
I recall Furuno last used a 2K25 Klystron in the KRA 121 Series Radars
which was before Northen picked up the Furuno Dealership. Don
Hollingsworth Sr. at G & L Marine was the KRA-121 expert and has always
been the "Go To Guy" for Marine Radar Technical Information, even when
he was the Raytheon Marine Tech (Ray 1500/1700/1900) for the NorthWest,
and worked for U.G. Allen.

Man that does date me, in the North Pacific Marine Electronic Community.

Bruce in alaska

That's what I get for letting my mouth overrun my holeridden memory.
The Konel that I was remembering did have a Klystron, and came in an "up" or
"down" transceiver model. The one on the yacht/halibut boat had the "up"
version and I had to make a test cable to run the transceiver in the pilot
house. It would see a mile or two with the waveguide coupler pointed out the
window. Boss insisted on a dummy load when he was around, but that made the
NE-2 on a stick, or echoes from down the bay unavailable. (I think you
mentioned once that "real" technicians didn't bother with the stick)
I guess I didn't get Furuno tech bulletins farmed out to me in
Anacortes until maybe 1979....... isn't that about the time the "toilet
bowl" went from KRA112 to KRA124? (and about the same time as the phenolic
based boards in the display started burning between lands all over the
place? Best troubleshooting was in a dark room, turning off and on, watching
for glow or sparks. Of course it was hard to see smoke then, but you could
smell it pretty quickly.

Old Chief Lynn

radar questions
 

OK, KRA116!

radar questions
 

In article ,
"Lynn Coffelt" wrote:

That's what I get for letting my mouth overrun my holeridden memory.
The Konel that I was remembering did have a Klystron, and came in an "up" or
"down" transceiver model. The one on the yacht/halibut boat had the "up"
version and I had to make a test cable to run the transceiver in the pilot
house. It would see a mile or two with the waveguide coupler pointed out the
window. Boss insisted on a dummy load when he was around, but that made the
NE-2 on a stick, or echoes from down the bay unavailable. (I think you
mentioned once that "real" technicians didn't bother with the stick)
I guess I didn't get Furuno tech bulletins farmed out to me in
Anacortes until maybe 1979....... isn't that about the time the "toilet
bowl" went from KRA112 to KRA124? (and about the same time as the phenolic
based boards in the display started burning between lands all over the
place? Best troubleshooting was in a dark room, turning off and on, watching
for glow or sparks. Of course it was hard to see smoke then, but you could
smell it pretty quickly.

Old Chief Lynn



Your confusing the KRA-124/248/448 Series, KRA1121 which preceeded it,
with the KRA-116 (ToiletBowl) and it's later cousins, the KRA-240 and
360. The Toilet Bowls all had HV Breakdown problems on the Main Display
boards, up untill the 240MKII's, when they redesigned the Trace paths
for the HV Section. The KRA-121's had 2K25 Klystrons, and were First
Generation, Marine Radars. KRA-124 Series were the first of the Second
Generation Radars, that had Gunn Diode LO's and the MKII versions had
Ring Circulators, instead of TR Cells. Third Generation Radars had
MMIC's, and Ring Circulators like the 1600's, 2400's and 701/1001 Series.
I put one of the first KRA-116's on the little Harbor Tug Western Towboat
had called the Wasp. It was a preproduction unit and ran for 6 hours
before the Inverter Board in the Powersupply went up in smoke. Old
Man Shrewsbury, wasn't so sure that these Jap Radars were any good after
that fiasco, cause it took a week to get a new board out of the factory
in Japan. Now if you look on any of the Western Towboat Tugs you will
see 100% Furuno Radars everywhere in their Fleet.

Bruce in alaska
--
add a 2 before @

radar questions
 

.. Your confusing the KRA-124/248/448 Series, KRA1121 which preceeded it,
with the KRA-116 (ToiletBowl) and it's later cousins, the KRA-240 and
360. The Toilet Bowls all had HV Breakdown problems on the Main Display
boards, up untill the 240MKII's, when they redesigned the Trace paths
for the HV Section. The KRA-121's had 2K25 Klystrons, and were First
Generation, Marine Radars. KRA-124 Series were the first of the Second
Generation Radars, that had Gunn Diode LO's and the MKII versions had
Ring Circulators, instead of TR Cells. Third Generation Radars had
MMIC's, and Ring Circulators like the 1600's, 2400's and 701/1001 Series.
I put one of the first KRA-116's on the little Harbor Tug Western Towboat
had called the Wasp. It was a preproduction unit and ran for 6 hours
before the Inverter Board in the Powersupply went up in smoke. Old
Man Shrewsbury, wasn't so sure that these Jap Radars were any good after
that fiasco, cause it took a week to get a new board out of the factory
in Japan. Now if you look on any of the Western Towboat Tugs you will
see 100% Furuno Radars everywhere in their Fleet.

Bruce in alaska

Yup, I did confuse the KRA1121 with the KRA-124 to 448 series, The only
1121 I worked on, then was the one on the Yacht/halibut boat. The KRA-124 to
448's were about 50% of the installations on our ferry contract. The rest
were Decca group 9's. The toilet bowl, was surely an interesting concept,
and when they became FR240's and up, with a vented toilet bowl they were a
real class act. (for the time...... of course)
Thanks for helping clear some fog!
Old Chief Lynn