I tried to find any specification throgh the local dealer, and he did
not even get an answer at Sea Ray in the States (neither yes nor no,
essentially along the lines of we do not supply it so we do not know):

I would like to have a 4'/22kg Radar antenna on a Sea Ray 315 Sundancer
Sport Spoiler, Molded Fiberglass (Seamless) w/Overhead Lighting.

Is this workable, as I do not seem to get an answer from SeaRay?
Or is there a lower weight limit so I would have to forego the
advantages of a big enough antenna?

TIA

Marc

--
Switzerland/Europe
http://www.heusser.com
remove CHEERS and from MERCIAL to get valid e-mail

Marc Heusser alid
wrote in :

I tried to find any specification throgh the local dealer, and he did
not even get an answer at Sea Ray in the States (neither yes nor no,
essentially along the lines of we do not supply it so we do not know):

I would like to have a 4'/22kg Radar antenna on a Sea Ray 315 Sundancer
Sport Spoiler, Molded Fiberglass (Seamless) w/Overhead Lighting.

Is this workable, as I do not seem to get an answer from SeaRay?
Or is there a lower weight limit so I would have to forego the
advantages of a big enough antenna?

TIA

Marc


Marc, let's take a look at reality on radar......

Radar cannot see further than the horizon.

The horizon depends on how far UP the antenna is mounted.

From your SR31, we're up just above the flybridge. How far can YOU see
with binoculars...6 miles? 5? Check it out.

If we had a 500KW military surface search radar on your arch, it could
"see" targets 6 miles away....maybe 8 or 9 if they are TALL targets like
lighthouses, radio towers, etc. So, what's the point?

You're not as tall as a containership, who can use a more powerful radar.
So, why waste money on HIS radar transceiver??

From up there, how about the 4KW radome? Loading on both the arch and
your electrical system are lots less, also your wallet. 4KW has no
trouble making a target at 8 miles. Ours is only 2KW on the sailboat,
but we don't have it high up because if you put the antenna up high you
CANNOT SEE THAT DAMNED BOUY YOU ARE ABOUT TO RUN OVER IN THE FOG because
the high antenna is shooting right over the top of it. Ours is up 35' on
the mizzenmast, probably higher than your arch. It can see the dock 3
slips away, plenty of return from that bouy in the fog.

I know the big swinging radar horn impresses the other sailors and looks
cool like you're an aircraft carrier....but why?....(c;

Besides, you're not going 400 knots like a jet. If you can see targets 2
miles away you have MINUTES to turn away...not seconds. That's far
enough for collision avoidance isn't it?

Larry
--
While in Mexico, I didn't have to press 1 for Spanish.
While in Iran, I didn't have to press 1 for Farsi, either.
While in Florida, I had to press 2 for English.
It just isn't fair.

"Larry" wrote in message ...
Marc Heusser alid
wrote in :

I tried to find any specification throgh the local dealer, and he did
not even get an answer at Sea Ray in the States (neither yes nor no,
essentially along the lines of we do not supply it so we do not know):

I would like to have a 4'/22kg Radar antenna on a Sea Ray 315 Sundancer
Sport Spoiler, Molded Fiberglass (Seamless) w/Overhead Lighting.

Is this workable, as I do not seem to get an answer from SeaRay?
Or is there a lower weight limit so I would have to forego the
advantages of a big enough antenna?

TIA

Marc


Marc, let's take a look at reality on radar......

Radar cannot see further than the horizon.

The horizon depends on how far UP the antenna is mounted.

From your SR31, we're up just above the flybridge. How far can YOU see
with binoculars...6 miles? 5? Check it out.

If we had a 500KW military surface search radar on your arch, it could
"see" targets 6 miles away....maybe 8 or 9 if they are TALL targets like
lighthouses, radio towers, etc. So, what's the point?

snip....


Though you might not see targets farther, with a larger antenna you would
have a better resolution, and that would be a good thing, don't you think?


snip....

Larry
--
While in Mexico, I didn't have to press 1 for Spanish.
While in Iran, I didn't have to press 1 for Farsi, either.
While in Florida, I had to press 2 for English.
It just isn't fair.

Harbin Osteen wrote:
"Larry" wrote in message ...


Larry
--
While in Mexico, I didn't have to press 1 for Spanish.
While in Iran, I didn't have to press 1 for Farsi, either.
While in Florida, I had to press 2 for English.
It just isn't fair.



Poor baby. Some of us speak and read more than one language. You should
have paid attention in school. Last time we were in Mexico, we spoke
"schoolbook" Spanish for the first few days, and then managed to pick up
on Mexican Spanish enough to feel at ease.

In article ,
Larry wrote:

....
Radar cannot see further than the horizon.
The horizon depends on how far UP the antenna is mounted.

I know - MSEE and lots of experience in this band in military service.

I am more interested in the mechanics of SR arches than electronics.

From your SR31, we're up just above the flybridge. How far can YOU
see
with binoculars...6 miles? 5? Check it out.

If we had a 500KW military surface search radar on your arch, it could
"see" targets 6 miles away....maybe 8 or 9 if they are TALL targets like
lighthouses, radio towers, etc. So, what's the point?

In a word: Resolution. A radome antenna has 4 to 6 degrees horizontal
beam width, a 4' slot antenna less has 1.8 degrees. Makes all the
difference in tight places like rivers. Like seeing one or two ships. Or
a small ship or sea clutter.
I would go as far as saying that horizontal resolution is the only
specification to worry about. What has not been captured by the antenna
is never going to show up on the display.

You're not as tall as a containership, who can use a more powerful radar.
So, why waste money on HIS radar transceiver??

From up there, how about the 4KW radome? Loading on both the arch and
your electrical system are lots less, also your wallet. 4KW has no
trouble making a target at 8 miles.

I AM talking about 4 kW, no more. What did you expect?

....
I know the big swinging radar horn impresses the other sailors and looks
cool like you're an aircraft carrier....but why?....(c;

I have no TV antenna, a 6" VHF antenna only, and no satellite dish
compensated for the movements ... sorry, no need to impress. I'd rather
be sailing anyway but it is not possible.


Besides, you're not going 400 knots like a jet. If you can see targets 2
miles away you have MINUTES to turn away...not seconds. That's far
enough for collision avoidance isn't it?

As I said above: It's all about resolution. Like seeing a small boat
without lights when going 25 knots in darkness.

Do you know what the actual permissible mechanical load would be on my
arch?

TIA

Marc

--
Switzerland/Europe
http://www.heusser.com
remove CHEERS and from MERCIAL to get valid e-mail

"HK" wrote in message
...
Harbin Osteen wrote:
"Larry" wrote in message
...


Larry
--
While in Mexico, I didn't have to press 1 for Spanish.
While in Iran, I didn't have to press 1 for Farsi, either.
While in Florida, I had to press 2 for English.
It just isn't fair.



Poor baby. Some of us speak and read more than one language.

But you understand English.........right?

My grandparents (both sides) learned English when they came over. They also
came over legally, as did millions of other immigrants.

Folks with your type of thinking have ruined America and the future quality
of life for my children, grandchildren.........etc.........

I feel sorry for them based on the world they will be living in.

Thanks Harry.

JimH wrote:
"HK" wrote in message
...
Harbin Osteen wrote:
"Larry" wrote in message
...


Larry
--
While in Mexico, I didn't have to press 1 for Spanish.
While in Iran, I didn't have to press 1 for Farsi, either.
While in Florida, I had to press 2 for English.
It just isn't fair.


Poor baby. Some of us speak and read more than one language.

But you understand English.........right?

My grandparents (both sides) learned English when they came over. They also
came over legally, as did millions of other immigrants.

Folks with your type of thinking have ruined America and the future quality
of life for my children, grandchildren.........etc.........

I feel sorry for them based on the world they will be living in.

Thanks Harry.




I've been visiting Florida for decades, starting in the 1960s. The first
time we went to Miami, I practiced my high school Spanish down there.
People speaking Spanish is nothing new. There are just more folks doing
that now. When we lived in Florida, and it was North Florida, we spoke
English and Spanish, and English mixed with Spanish.

Americans are intellectually lazy. An awful lot of those born here with
"anglo" parents can barely speak or write plain high-school level
English. No wonder they can't pick up a little Spanish, eh?

Your boy Bush has done nothing to close the leakage at the borders for
the past seven years. He's your boy...why isn't he doing what you want?

"Harbin Osteen" wrote in
:

Though you might not see targets farther, with a larger antenna you
would have a better resolution, and that would be a good thing, don't
you think?



That is true. If you have a huge antenna, you can see whether it's one
ship or 8 ships close together. That might be important for missile
launching, but does it really matter in a boat? INstead of 3 tiny targets
on the tiny screen...you get one big blob you can't miss on the cheap
antenna. Too much resolution isn't a good thing on a small boat whos
antenna is rolling and pitching so awful in the swells.

Larry
--
While in Mexico, I didn't have to press 1 for Spanish.
While in Iran, I didn't have to press 1 for Farsi, either.
While in Florida, I had to press 2 for English.
It just isn't fair.

"HK" wrote in message
...
JimH wrote:
"HK" wrote in message
...
Harbin Osteen wrote:
"Larry" wrote in message
...


Larry
--
While in Mexico, I didn't have to press 1 for Spanish.
While in Iran, I didn't have to press 1 for Farsi, either.
While in Florida, I had to press 2 for English.
It just isn't fair.


Poor baby. Some of us speak and read more than one language.

But you understand English.........right?

My grandparents (both sides) learned English when they came over. They
also came over legally, as did millions of other immigrants.

Folks with your type of thinking have ruined America and the future
quality of life for my children, grandchildren.........etc.........

I feel sorry for them based on the world they will be living in.

Thanks Harry.


I've been visiting Florida for decades, starting in the 1960s. The first
time we went to Miami, I practiced my high school Spanish down there.
People speaking Spanish is nothing new. There are just more folks doing
that now. When we lived in Florida, and it was North Florida, we spoke
English and Spanish, and English mixed with Spanish.
Americans are intellectually lazy


Ahh.....so Americans need to learn Spanish...eh?

Like I said in another thread, you continue to amaze me. ;-)

Marc Heusser alid
wrote in :

In a word: Resolution. A radome antenna has 4 to 6 degrees horizontal
beam width, a 4' slot antenna less has 1.8 degrees. Makes all the
difference in tight places like rivers. Like seeing one or two ships.
Or
a small ship or sea clutter.
I would go as far as saying that horizontal resolution is the only
specification to worry about. What has not been captured by the antenna
is never going to show up on the display.


Ok, let's talk about the low vs high resolution antennas....

Low is simple, it has a huge beamwidth, relatively speaking. When the
boat is rolled over and the antenna towards the target is pointing,
mostly, into the sea, its wide vertical antenna pattern is more likely to
see "something" out 4 miles on this rotation. Because the target is "in
the beam" for a much longer length of time, as the beam rotates around
during this rolling/pitching motion of the boat, the receiver is more
likely to see the target for that brief instant the antenna isn't pointed
at the moon or Davy Jones' Locker, than it would be if the beam were
"really narrow" where, even if the antenna were mounted on a oil rig and
not pitching and rolling on a Sea Ray...31' or not. Every rotation of a
really narrow beam antenna only leaves the target illuminated with RF and
looking through that really narrow "slot" with the receiver for a much
shorter instance.

Try it. Touch your middle finger to your thumb making a big hole to look
through. Stand rigid on the rolling/pitching deck without trying to keep
your "sight" on the "target" way off in your vision. The target shows up
in the big hole all the time you're looking through it....and would
return our radar RF to the receiver looking through that hole so we'd get
a return on the screen.

Now, roll your forefinger up as tight as you can in the crook of your
thumb, making a small hole to simulate looking at the same target through
this massive, high resolution, antenna array. Point this hole at the
target, but stand rigid not trying to follow the target around with the
pitching and rolling of the boat. You can hardly see the target any more
as it rolls in and out of the hole. The only time the receiver will see
the target is when its rotating by the target synchronizes with the boat
being somewhat level, which happens less and less often as the hole gets
smaller.

Actually, the hole, the window the radar looks through is a narrow
vertical slot, narrow horizontally but, we hope with all that
rolling/pitching, WIDE vertically. But, you get the idea of what I'm
talking about.

Another low vs high phenomenon that's pretty easy to grasp is in waves
and troughs. The low-res antenna, the big hole, paints the target far
longer than the high-res, narrow beam antenna. Being wide, it has a far
better chance of seeing "something" if the waves are high because it
paints the target LONGER on each rotation. The very short painting the
high res big antenna does, has less chance of seeing the target around
the coincidental wave.

All this is why surface search radars on big ships, even Navy/CG ships,
is a relatively small, large aperture antenna, not some huge, high-gain
array with really high resolution....which is the targeting antenna for
the missiles/gunnery.

There's still that CLOSE IN target, the one you are about to run over....

It's ALWAYS much better to paint all the targets in that 1/8th mile
range, no matter whether it's the return from a 40hp Yamaha outboard, the
only radar reflector on his plastic fishing boat, or the little nun bouys
in the channel. The CLOSE IN targets really need to make a blob in the
rainstorm and fog....to hell with containerships 12 miles away. That's
why it's VERY important to keep the antenna LOW, not shooting over the
targets just so you can see that containership and brag about it to
"her".

Larry
--
While in Mexico, I didn't have to press 1 for Spanish.
While in Iran, I didn't have to press 1 for Farsi, either.
While in Florida, I had to press 2 for English.
It just isn't fair.