Radar effectivness
 

Is there any advantages in having a 4kw as opposed to 2kw antenna
apart from the additional range. Which for me is a unwanted feature.

Will the higher powered unit detect targets in close proximity (less
than a mile) that would possibly have not been detected by the lower
powered unit or is everything just lost in sea clutter.

Has anyone had experience of changing to a more higher power antenna
and the possible advantages.

Radar effectivness
 

beryl must be edykated coz e writed:

Is there any advantages in having a 4kw as opposed to 2kw antenna
apart from the additional range. Which for me is a unwanted feature.

Will the higher powered unit detect targets in close proximity (less
than a mile) that would possibly have not been detected by the lower
powered unit or is everything just lost in sea clutter.

Has anyone had experience of changing to a more higher power antenna
and the possible advantages.

A bigger, i.e. greater diameter antenna will give a narrower band of
definition but the output power is primarily for range. Also can your "head"
unit operate with an alternate Radome?

--
Ian

Radar effectivness
 

On Fri, 22 Aug 2003 10:01:53 +0100, beryl
wrote:

Is there any advantages in having a 4kw as opposed to 2kw antenna
apart from the additional range. Which for me is a unwanted feature.

Will the higher powered unit detect targets in close proximity (less
than a mile) that would possibly have not been detected by the lower
powered unit or is everything just lost in sea clutter.

Has anyone had experience of changing to a more higher power antenna
and the possible advantages.

The higher powered units use a wider pulse width to increase range,
too. This results in lower definition of targets. Once the reflected
signal off an object is above the receiver's noise floor, the tiniest
signal it will receive, nothing is gained. Fine tuning the receivers
frequency, mostly an electronic control on the screen in new radars,
DOES make it more sensitive to the reflections from the transmitter,
however.

Many sailors interested in seeing the bouy on their radars also make
the mistake of putting the radar antennas up so high they shoot right
over the bouy they are trying to detect CLOSE to the boat. Increasing
the antenna height is great for extending RANGE. But, why does a
sailboat moving 8 knots need range? He needs to see that outer marker
in the fog that's 800 yards from the bow.....If he'd move the radar
antenna DOWN to 20' off the water and from BEHIND the rigging looking
forward, it would stick out like a sore thumb, even on the 2KW
radar.....(c;



Larry W4CSC

Maybe we could get the power grid fixed if every politician
regulating the power companies wasn't on their payrolls.

Radar effectivness
 

beryl must be edykated coz e writed:


A bigger, i.e. greater diameter antenna will give a narrower band of
definition but the output power is primarily for range. Also can your "head"
unit operate with an alternate Radome?


Yes not a problem for I am buying a complete new system.
The processor board in the present one has gone "pop"
and is past economical repair plus it would not comply
long term with the changing spurious emissions requirements

I am just replacing one for a customer who has had a similar problem, his
current radar is no longer supported by the manufacturer, so it is more
economical to fit a whole new set.

--
Ian

Radar effectivness
 

On Fri, 22 Aug 2003 09:43:30 -0400 (EDT), (Ron
Thornton) wrote:

It used to be generally excepted that you needed at least 4kw to punch
thru rain.

Interesting historical note. How long ago was that?



Rodney Myrvaagnes NYC J36 Gjo/a


"Nuke the gay whales for Jesus" -- anon T-shirt

Radar effectivness
 

Rodney,

About 2 years ago. A google search of the boats groups should find a
number of comments from both users and radar techs.

Ron

Radar effectivness
 

beryl wrote:

Is there any advantages in having a 4kw as opposed to 2kw antenna
apart from the additional range. Which for me is a unwanted feature.

Will the higher powered unit detect targets in close proximity (less
than a mile) that would possibly have not been detected by the lower
powered unit or is everything just lost in sea clutter.

Has anyone had experience of changing to a more higher power antenna
and the possible advantages.

Range vs noise rejection:

If the antenna is low, it will see less clutter, and will have
shorter range.
If the AE is high, it will see less close in, and see more
including clutter, far away.

--
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purpose is THEFT and PLAGIARISM. Abuse is Invasion of privacy
and harassment. Abusers may be prosecuted. -This notice footer
released to public domain. Spamspoof salad by spamchock -
SofDevCo

Radar effectivness
 

On Sat, 23 Aug 2003 14:41:28 -0400 (EDT), (Ron
Thornton) wrote:

Rodney,

About 2 years ago. A google search of the boats groups should find a
number of comments from both users and radar techs.

Well, I have no doubt 4KW is better than 2KW, but the simple 1.5 KW
Furuno 1720 I used from 1989 to 2001 could see significant targets in
rain. It took to much manual diddling to do so, in retrospecy.

The 2KW Raytheon I got in Sept 2001 is highly computerized, and its
default behavior is better than I could do manually, I am sure.

One clever thing it does is show rainshowers on 6 NM range, and filter
them out on 3 NM, allowing me to see other boats. Popping back and
forth is remarkably informative.

This is not a plug for Raytheon. I expect a Furuno with present-day
technology is similarly improved, perhaps with different emphasis.

That said, if I were equipping a power boat, or a sailboat so heavy
that the radar antenna weight is not a consideration, I would go for
the most powerful I could afford. But the Raytheon has more capability
than I expected, and weighs enough more than the Furuno to bother me.

Indeed, I had to get a sturdier tower. :-(



Rodney Myrvaagnes NYC J36 Gjo/a

"Happy is he that taketh thy little ones and dasheth them upon the stones." __Psalm 137

Radar effectivness
 

I am just replacing one for a customer who has had a similar problem, his
current radar is no longer supported by the manufacturer, so it is more
economical to fit a whole new set.


And which power rating are you fitting, and what was the thinking
behind the selection.

Radar effectivness
 

Range vs noise rejection:

If the antenna is low, it will see less clutter, and will have
shorter range.
If the AE is high, it will see less close in, and see more
including clutter, far away.


What would consider optimum height for the antenna when
mainly used on short range, (up to 5 miles) in bad weather conditions.

Radar effectivness
 

On Sun, 24 Aug 2003 23:59:06 -0400 Rodney Myrvaagnes wrote:

What would consider optimum height for the antenna when
mainly used on short range, (up to 5 miles) in bad weather conditions.

I put mine about 11 feet off the water. High enough to be well over
our heads in the cockpit, but low enough so sea clutter doesn't bother
a lot. I did this first after using the same kind as my first radar on
a friend's boat. He had it mounted on the mast, about 20 feet up. The
clutter really was a detriment.

I have JRC 1000 mounted about 3 meters (~10 feet) above the water. I can see
big ships at 6-8 nautical miles range and I consider it enough. On the other
hand, I can see little buoys at 0.2 nautical miles and it is enough too. In
general I am very pleased with my radars performance.

matti

--
"China is a big country, inhabited by many chinese." - Charles de Gaulle

Radar effectivness
 

I have used both the 2kw and 4kw Raytheon radars. The 4kw gives brighter and
better defined targets than the 2kw. It will pick up small bay bouys at 1-2
miles where the 2kw won't pick them up until within 1 mile.

With your 4kw unit at the 1-2 mile range what roughly are the size
of the buoys
you can pick up and at .125 of a mile what would be the smallest
object you would detect.

Radar effectivness