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.

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.

"Lloyd Sumpter" wrote in message
...
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?

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?

Lloyd Sumpter
"Far Cove" Catalina 36


You may not plan to venture out there if its foggy but what if you are
already in transit or need to get from A to B?

There is a fellow in my Nanaimo marina who spent all year fitting out his
36' Seabird to sail it down to Mexico this Fall. This is the second time
he's tried. Last year they got into a vicious storm off Washington and
turned back. This year they set out from Victoria and got into pea soup fog
somewhere West. Had no radar and decided they couldn't risk colliding with
shipping. Turned back again. Maybe having radar would save a lot of
planned trips as well as make trips-in-progress safer.
Darned expensive though compared to a chart plotter, especially if you go
high-tech for the radome mount and pay someone else to install it all. I
have the radar but I'm still saving for the mount.

As for pole mounts, there does not seem to be an issue with blind spots.
Aside from simplifying the installation I've been told that a malfunctioning
radar often results from problems in the radome so a pole or backstay mount
simplifys removing this unit for servicing. I've also been advised to use a
2" diameter pole to reduce vibration and not to go too high for the same
reason.
Gord

"Lloyd Sumpter" wrote in message
...
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?

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?

Lloyd Sumpter
"Far Cove" Catalina 36


You may not plan to venture out there if its foggy but what if you are
already in transit or need to get from A to B?

There is a fellow in my Nanaimo marina who spent all year fitting out his
36' Seabird to sail it down to Mexico this Fall. This is the second time
he's tried. Last year they got into a vicious storm off Washington and
turned back. This year they set out from Victoria and got into pea soup fog
somewhere West. Had no radar and decided they couldn't risk colliding with
shipping. Turned back again. Maybe having radar would save a lot of
planned trips as well as make trips-in-progress safer.
Darned expensive though compared to a chart plotter, especially if you go
high-tech for the radome mount and pay someone else to install it all. I
have the radar but I'm still saving for the mount.

As for pole mounts, there does not seem to be an issue with blind spots.
Aside from simplifying the installation I've been told that a malfunctioning
radar often results from problems in the radome so a pole or backstay mount
simplifys removing this unit for servicing. I've also been advised to use a
2" diameter pole to reduce vibration and not to go too high for the same
reason.
Gord

"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?

"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

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


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?

My understanding is that this is reliant on the radar band in which
they are operating their active radar, and/or whether they have a
receiver that goes ping (or whatever) when glanced by "yachtie" radar.

R.