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DSK
 
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Default Radar vs GPS/Sounder

Jim Thompson wrote:

I bought radar before this past season for the first time. Real "eye
opener". Found it very useful, even in clear weather -- we only get
fog 4 day/month in the Northumbeland Strait. If I was venturing out
on a longer range trip I would not be without GPS, sounder and radar.


We have a radar set on the tugboat. A bit old, and doubtfully installed by DPO, but
it seemed capable of working. The return was very garbled and unclear, it would not
even pick up large buildings on shore from more than 1/2 mile away. I was convinced
that we should buy a new one, but going through the tuning & timing procedure in the
owners manual (at least the DPO saved them) improved the return picture a LOT.

Over the past year I've tweaked the thing a little here and there, as time &
opportunity came along, and after some coaching by a retired Navy OS Master Chief, we
get a great return picture out to about 16 miles. It will pick up a floating soda can
in calm water, show rain squals, outline marshy shore, etc etc.

Our radar has proven to be a really good tool for use in marginal visibility and for
tracking ship traffic. When we first bought the boat I was not convinced of it's
usefulness, especially not that particular set. But now it works great.

BTW thanks Jeff for your comments about magnetron life.

Fresh Breezes- Doug King

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Default Radar vs GPS/Sounder

On Tue, 25 Nov 2003 09:50:07 -0500, DSK wrote:



Our radar has proven to be a really good tool for use in marginal visibility and for
tracking ship traffic. When we first bought the boat I was not convinced of it's
usefulness, especially not that particular set. But now it works great.


One last thing I forgot to mention: Here on Lake Ontario many summer
storms appear as "pop-up" cumulonimbus thunderheads, with 50-60 knot
line squalls that can lay you flat if you have, as most do most of the
time, a full hoist...

There's only 20-30 miles to the west end of the lake here (Toronto)
and squalls that develop at that end (south to west, usually) can get
here in minutes.

A properly tuned radar will show squall lines quite sharply. If its
blasting at you at 48 knots and you catch it on radar aft at 12 NM,
you can shorten sail in a timely fashion and ride out an otherwise
very unpleasant, possibly expensive and potentially dangerous 15
minute surfing session.

And of course, if you can see rain bands, you can sail between them,
if the wind and waves allow.

R.
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Default Radar vs GPS/Sounder

On Tue, 25 Nov 2003 09:50:07 -0500, DSK wrote:



Our radar has proven to be a really good tool for use in marginal visibility and for
tracking ship traffic. When we first bought the boat I was not convinced of it's
usefulness, especially not that particular set. But now it works great.


One last thing I forgot to mention: Here on Lake Ontario many summer
storms appear as "pop-up" cumulonimbus thunderheads, with 50-60 knot
line squalls that can lay you flat if you have, as most do most of the
time, a full hoist...

There's only 20-30 miles to the west end of the lake here (Toronto)
and squalls that develop at that end (south to west, usually) can get
here in minutes.

A properly tuned radar will show squall lines quite sharply. If its
blasting at you at 48 knots and you catch it on radar aft at 12 NM,
you can shorten sail in a timely fashion and ride out an otherwise
very unpleasant, possibly expensive and potentially dangerous 15
minute surfing session.

And of course, if you can see rain bands, you can sail between them,
if the wind and waves allow.

R.
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DSK
 
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Default Radar vs GPS/Sounder

Jim Thompson wrote:

I bought radar before this past season for the first time. Real "eye
opener". Found it very useful, even in clear weather -- we only get
fog 4 day/month in the Northumbeland Strait. If I was venturing out
on a longer range trip I would not be without GPS, sounder and radar.


We have a radar set on the tugboat. A bit old, and doubtfully installed by DPO, but
it seemed capable of working. The return was very garbled and unclear, it would not
even pick up large buildings on shore from more than 1/2 mile away. I was convinced
that we should buy a new one, but going through the tuning & timing procedure in the
owners manual (at least the DPO saved them) improved the return picture a LOT.

Over the past year I've tweaked the thing a little here and there, as time &
opportunity came along, and after some coaching by a retired Navy OS Master Chief, we
get a great return picture out to about 16 miles. It will pick up a floating soda can
in calm water, show rain squals, outline marshy shore, etc etc.

Our radar has proven to be a really good tool for use in marginal visibility and for
tracking ship traffic. When we first bought the boat I was not convinced of it's
usefulness, especially not that particular set. But now it works great.

BTW thanks Jeff for your comments about magnetron life.

Fresh Breezes- Doug King

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Jim Thompson
 
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Default Radar vs GPS/Sounder

I bought radar before this past season for the first time. Real "eye
opener". Found it very useful, even in clear weather -- we only get
fog 4 day/month in the Northumbeland Strait. If I was venturing out
on a longer range trip I would not be without GPS, sounder and radar.

Jim
http://jimthompson.net/boating/ECharting/JRC1500.htm

On Sun, 23 Nov 2003 09:07:50 -0800, "Lloyd Sumpter"
wrote:

Hi,

Thinking of getting radar for Far Cove, mainly for this planned trip to WCVI,
which has lots of fog.

Now, I've survived 20+ years of sailing Georgia Strait, etc. without radar.
If it's really foggy, I just stay put. If I venture out, I use several nav aids
including GPS to determine my position, blow my horn and listen.

I'm thinking that, even WITH radar, I wouldn't venture out in unfamiliar
waters in dense fog. And if I was out and the fog rolled in on me, I would think
that GPS, sounder and a good chart would be better to find that anchorage than
radar, assuming I could see at least 100 ft or so.

Comments?





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On Sun, 23 Nov 2003 09:07:50 -0800, "Lloyd Sumpter"
wrote:

Hi,

Thinking of getting radar for Far Cove, mainly for this planned trip to WCVI,
which has lots of fog.

Now, I've survived 20+ years of sailing Georgia Strait, etc. without radar.
If it's really foggy, I just stay put. If I venture out, I use several nav aids
including GPS to determine my position, blow my horn and listen.

I'm thinking that, even WITH radar, I wouldn't venture out in unfamiliar
waters in dense fog. And if I was out and the fog rolled in on me, I would think
that GPS, sounder and a good chart would be better to find that anchorage than
radar, assuming I could see at least 100 ft or so.


Under ideal conditions, you are correct. The benefit of radar,
however, is that you can see what you can't hear, i.e. other shipping
that has no intention of letting a little fog screw with the
schedule...

Also, to a lesser extent, you become visible to other shipping in a
way that a horn can't: precisely.

Finally, you can use a radar to get bearings on shore objects at night
if the GPS conks out and it's too cloudy to use celestial...which I
notice you didn't mention...G

I would say radar, sensibly used, complements but doesn't replace
paper, GPS, depth sounders, horns and good old seamanship. While it is
possible to get swamped with "too much information", particularly if
it doesn't agree, too little information is often what proves fatal to
the boat.

Comments?

Also, if I mount the radome on a post at the stern like most seem to, doesn't
the mast and sail interfere with it looking forward?


Yes, but barely, or at least not as much as you'd think. You can
offset the radome on a pole and gimbal off a stern quarter if you
wish, and then the "blind spot" would be 10 deg. port or starboard
looking forward.

I agree, a gimbal mount at the cross-trees is probably ideal, however,
but it's easier to get at stuff on a pole. Probably the nicest option
is an arch with the radar offset and a way to lash the boom, hang
bimini canvas, affix a GPS, VHF, etc., and yet keep all within easy
reach.

R.

Lloyd Sumpter
"Far Cove" Catalina 36


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Jeff Morris
 
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Default Radar vs GPS/Sounder

wrote in message
...
...
Also, to a lesser extent, you become visible to other shipping in a
way that a horn can't: precisely.


This is a point I've wondered about: it seems that vessels with active radar
appear on my radar with a large arc centered on the vessel's blip. I've assumed
this is an interaction between their radar and mine. Does this also mean that
my radar also enhances my picture on their screen?

-jeff



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Gary Schafer
 
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Default Radar vs GPS/Sounder

On Tue, 25 Nov 2003 21:42:50 -0500, "Jeff Morris"
wrote:

wrote in message
.. .
...
Also, to a lesser extent, you become visible to other shipping in a
way that a horn can't: precisely.


This is a point I've wondered about: it seems that vessels with active radar
appear on my radar with a large arc centered on the vessel's blip. I've assumed
this is an interaction between their radar and mine. Does this also mean that
my radar also enhances my picture on their screen?

-jeff




Don't count on it. The arc that you see from the other guys radar is
from interference from his transmitter. Your radar is picking up your
transmitters echo and his transmitter directly. His pulses are not
synchronized with yours so you see the trail of pulses from his
transmitter while your transmitter is between pulses. It will give
neither of you any indication of where the other is.

This only happens if the two transmitters are very close to the same
frequency. Even though the two radar's may be exactly the same type of
radar, they may or may not be close enough to the same frequency. The
magnetrons are all tuned slightly different and drift somewhat.

On most radar's there is also an interference filter on the receivers
that eliminate or reduce that type of interference.

Then too the other ship may be using a radar in a completely different
band. No interference to either of you.

Regards
Gary

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otnmbrd
 
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Default Radar vs GPS/Sounder



Jeff Morris wrote:
wrote in message
...

...
Also, to a lesser extent, you become visible to other shipping in a
way that a horn can't: precisely.



This is a point I've wondered about: it seems that vessels with active radar
appear on my radar with a large arc centered on the vessel's blip. I've assumed
this is an interaction between their radar and mine. Does this also mean that
my radar also enhances my picture on their screen?

-jeff



This may also be due to having the gain/intensity, turned up too high
for the given range scale you are using. It can sometimes be countered
with the anti clutter controls, alone.

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Jeff Morris
 
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Default Radar vs GPS/Sounder

"otnmbrd" wrote in message news:_I4xb.15704
This is a point I've wondered about: it seems that vessels with active

radar
appear on my radar with a large arc centered on the vessel's blip. I've

assumed
this is an interaction between their radar and mine. Does this also mean

that
my radar also enhances my picture on their screen?

This may also be due to having the gain/intensity, turned up too high
for the given range scale you are using. It can sometimes be countered
with the anti clutter controls, alone.


Who said I wanted to get rid of it? Its kind of nice have a special identifier
for some vessels. How can I enhance it?




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