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

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

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

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.

"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?

Jeff Morris wrote:
"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?

Problem is, what I feel you are describing, may not be due to
interference from another radar.
In the past, when I experienced interference, it showed more as a spoke
coming towards me, or a series of dots, behind the target (it tends to vary.
What you are are describing, sounds more like "side lobe" effect, in
which case it's not something you'd want to enhance .... course, I could
be miss reading/understanding your description.

otn

Jeff Morris wrote:
"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?

Problem is, what I feel you are describing, may not be due to
interference from another radar.
In the past, when I experienced interference, it showed more as a spoke
coming towards me, or a series of dots, behind the target (it tends to vary.
What you are are describing, sounds more like "side lobe" effect, in
which case it's not something you'd want to enhance .... course, I could
be miss reading/understanding your description.

otn

"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?

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

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.