In article ,
Steve Thrasher wrote:

Basically it boils down to: The higher the frequency of the beam, the
higher the frequency of the PRF (Pulse Repetition Frequency) and the
shorter your pulse length the better your resolution. Antenna size only
affects the signal strength the receiver sees, for the most part. Which
is assuming it's built for the proper frequency.

Bzzzt, Wrong answer, would you like to try again for what is behind
Door #2??????

It is a good thing you have all that Military Experiencee, but it really
doesn't translate into Commercial Marine Radar Experience. These two
senerios are Apples and Oranges, as they use similar Technology, but are
doing Totally Different Jobs andd providing Totally Different Data
to the Operator.

In Commercial Marine Radars the Antenna Horozontal and Vertical Beamwidth
ARE very significant factors in the Resolution of Targets on the PPI
type displays used. These two Specs set the Basic Operating ability
of the system to differrentiate between targets, at the same distance,
but sperated by small Azimuth Angles. The PRR (Pulse Repetition Rate)
sets the Maximum Range, along with Pulse Length, and in Commercial
Marine Radar is usually Fixed in two or three settings, determined by
the Range Switch Setting. The "Frequency of the Beam" in Commecrial
Marine Radars is FIXED, by the Spec'd Magnitron and in the USA, only
Xband and SBand, are Licensable under CFR 47 Part 80. Since Sband
Radars are very LARGE, you only find them on Vessels, usually over 1600
Tons or bigger, with 95% of the Commercial Marine Radars opeerating
at 10Ghz in the XBand.

If one wants to discuss the relative merits of PPR, PL, as opposed to
Antenna Gain, Vertical and Horozontal Beamwidths in the designing of
Commercial Marine Radars, Great, but 99% of the folks reading these
posts, don't understand the language, and don't have a clue about the
concepts used in the design of the Equipment that they buy, and install
on their Vessels. They just look at, if the Radar shows them what's
out around them, and hope they aren't missing something coming their way.

Bruce in alaska a Longtime Marine RadioMan, but now just
an Old Fart......
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add a 2 before @

Bruce in Alaska wrote:
Bzzzt, Wrong answer, would you like to try again for what is behind
Door #2??????

Sure lots of things were wrong, I did say I'd forgotten most of this
stuff. :-) Probably for good reason I might add, didn't put any beans
on my table.

But, the answer to what was being bandied about sort of boils down to
why the dish used for satellite service in Florida is a different size
than the one used in Alaska, ignoring all the boring stuff about
pitch/yaw and things like that.

Bruce in Alaska wrote in news:bruceg-
:

Bruce in alaska a Longtime Marine RadioMan, but now just
an Old Fart......
-

Bruce's radar still operates on a bedspring antenna on VHF....(c;

Now THAT's OLD!

Larry

In article ,
Larry wrote:

Bruce in Alaska wrote in news:bruceg-
:

Bruce in alaska a Longtime Marine RadioMan, but now just
an Old Fart......
-

Bruce's radar still operates on a bedspring antenna on VHF....(c;

Now THAT's OLD!

Larry

I actually DID work on one of those VHF Radars, as very young tech.
It was at a Military Museum, and I replaced the Dynamotor that suppiled
the HV for the Transmitter. I got the Dynamotor from a unit that was
"Scrapped in Place" half way up the Mountain at Alitak, Alaska on the
southern tip of Kodiak Island. It was installed during WWII, to do
Sea Search for the Japanese Navy approching Kodiak Island. I was able to
lug the Dynamotor, down off the mountain, on one of my trips to the top,
to service a Remote Base Marine VHF site I had installed at the summit.
It is amazing how far 25 Watts of VHF will go when the Antenna is at
3500 Ft. That Site was designed to work a Tropo Path, 235 Miles long,
to an associated Salmon Processor at Chignik, Alaska. Really worked
good most of the summer, untill a weather front would come thru and
dissrupt the Temprature Inversion Layer between the two locations.
Then it would go out, and it took a couple of days, to rebuild the
Inversion Layer, before the path would return. Now days, it is all
done by SatPhones, and Cellular. Oh well, MF/HF is just about DEAD,
as well, in the Maritime Community. Good thing I am reTIRED.....

Bruce in alaska
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add a 2 before @