Jeff Morris wrote:
What is ghosting?

An effect that can sometimes be seen on terrestrial TV sets - the set
receives the direct signal from the transmitter, and a secondary signal
which comes in a little later, typically the result of the transmitted
signal bouncing off of a building or hill.

It strikes me that a wide horizontal beam would result in a range of
reflections, or, perhaps more accurately, a reflection period which is a
function of the beam width and rotation speed.


--
Wally
www.makearatherlonglinkthattakesyounowhere.com
Things are always clearer in the cold, post-upload light.

No Jeff... I doubt I could explain that adequately expect I would think
horizontal beam width would affect resolution, range and maybe weather
penetration abilities.

CM

"Jeff Morris" jeffmo@NoSpam-sv-lokiDOTcom wrote in message
...
| So perhaps you or Neal can explain to everyone how the horizontal beam
width affect the
| image.
|
| -jeff
|
|
| Capt. Mooron wrote:
| Most people I've seen either find a radar image intuitively correct
| to what they see around them ... or they don't. I knew immediately
| what I was looking at on the first radar image I saw. I can
| interpolate between radar, air photo and chart in an instant. I
| mentally compensate for differences in scale and orientation. Maybe
| I'm one of the lucky few... but I assumed everyone had this ability
| to some extent.
|
| CM
|
| "Simple Simon" wrote in message
| ...
|
| But radar is different from a paper chart because
| a paper chart does not foreshorten the view while
| radar does. Radar is really no different than a
| looking at something with eyes that use radio
| waves instead of light waves
|
| Our eyes use light and when we see a hundred
| yards of water at a distance of a quarter mile this
| hundred yards of water looks a helluva lot shorter
| than the same hundred yards right off our bow.
|
| Radar 'sees' thing the same way so one must
| extrapolate this information mentally in order
| to match it with a chart of the same area.
|
| It would be much the same as equating a gnomic
| projection with a Mercator projection but backwards
| if looking north on a Mercator.
|
| See what I mean? But the point is the majority
| of people can't even imagine such differences
| let alone work with them.
|
| This is what I mean by spatial comprehension.
|
| S.Simon - a sailboat Captain who's superior to any and all motorboat
| Captains
|
| "Capt. Mooron" wrote in message
| ...
| Generally I find that women are at a loss when it comes to spatial
| comprehension. A man will usually automatically know the extended
| limits of an automobile when he sits in one. Women depend on
| mirrors and the visual depth of field at a specific spot to
| determine this. This is one of the reasons why women generally do
| not back into a parking space... while men prefer to. I say this is
| a general trait.... I know of women who are very good with spatial
| interpretation.
|
| If you look at the radar screen as a chart... it is easier to
| resolve the image and blend it to the area around you. Just keep in
| mind that often you only view the proximal reflected surface of any
| object. The "chart" on a radar screen is always oriented to the
| line of the vessel and bearing is always relative unless a fluxgate
| compass or GPS input is available. In a day or two I could easily
| have you running with a full comprehension of radar... at least as
| well as anyone else. Tuning radar is no problem....
|
| CM
|
| "Simple Simon" wrote in message
| ...
|
|
| I've met many people who cannot extrapolate a land map
| of an area they are familiar with much less be able to relate
| to a nautical chart. If tests were given for this type of relating
| a graphical representation to geography I bet you'd be
| apalled at the numbers of folks who simply can't relate.
|
| Bobsprit is probably one of these chart challenged people.
|
| Simple things like basic orientation of the map while they
| look at it leaves them at a loss. A radar display is even
| more of an alien representation that a paper chart. Is the
| display 'heads up' or "oriented north" for instance is more
| than many people can cope with. Spatial relationships
| and representative distances with respect to scale are
| concepts many simply cannot fathom. I've only used
| radar a couple of times and found it did not convey
| much information at all other than skewed and foreshortened
| spatial relationships that were difficult to stretch out into
| geographical reality in my mind - a mind which excels
| at spatiality.
|
| I can see where practice, practice, practice and a mind
| that can understand is vital for a radar operator. This is
| yet another reason I think there should be a navigator at
| the helm of large ships. Let the navigator navigator - let
| the Captain steer according to input from the navigator.
|
| S.Simon - a Captain who knows how things work
|
|
|
|
| "Capt. Mooron" wrote in message
| ...
|
| "Shen44" wrote in message
|
| Radar is an aid to navigation, that is well learned if one has
| one,
| but
| not as
| important to learn for beginners, as some of the other basics,
| such as compass, chart work, etc..
| Contrary to what some may think, radar is not something you can
| just
| turn
| on,
| for the first time, and be instantly familiar and competent with
| it's usage. I have seen any number of people using it on a
| fairly regular
| basis,
| who
| have
| problems tuning (and sometimes detuning) for best picture, then
| equating that picture to their charts or vessel traffic around
| them.
| Without knowing the basics of relative motion and how to plot
| targets,
| you
| can
| easily get yourself into as much trouble as you can avoid.
|
| Maybe these people are the same ones with spatial difficulties. I
| haven't seen anyone that has had a problem understanding a radar
| image... tuning radar is a little more complicated ... but not
| out of the realm of the newbie.
|
| While I concur that Basic Navigation is primary obstacle to
| overcome... a radar in use to confirm your plots and verify
| relative bearings is perfectly fine.
|
| The days of high tech being utilized only on large ships is over.
| Navigational instrumentation is now available to the layman and
| the general population's ability to embrace technology has
| increased dramatically.
|
| CM
|
|

"Bobsprit" wrote in message
...
| | I dare you to show the post where I claimed the above!
|
| Oh Boo Hooo Hooo cried Bob!
|
| BUSTED and caught in another lie!


Oh dear... he's wailing again.... I did not lie Bob! You did but can't
remeber where or you would be posting a link.

Bwahahahahahahahahaaa!!

CM

Wally wrote:
Jeff Morris wrote:
What is ghosting?

An effect that can sometimes be seen on terrestrial TV sets - the set
receives the direct signal from the transmitter, and a secondary
signal which comes in a little later, typically the result of the
transmitted signal bouncing off of a building or hill.

It strikes me that a wide horizontal beam would result in a range of
reflections, or, perhaps more accurately, a reflection period which
is a function of the beam width and rotation speed.

So, at any given moment, the receiver is getting a return which is based on
the range of topographical features being hit by the beam. If those features
are different distances away (or different materials/densities?), then the
return would, I think, be confused - all sorts of possibilities for what
would appear to be several targets in the nominal direction; maybe harmonic
weirdness. I dunno - I'm half-guessing.



--
Wally
www.makearatherlonglinkthattakesyounowhere.com
Things are always clearer in the cold, post-upload light.

That's easy. A narrow horizontal beam width permits accurate
bearing determination and good bearing resolution while a wide
width presents a better overall picture but with degraded bearing
determination and resolution.

I hope this helps.

S.Simon - a Captain who can use a search engine really fast


"Jeff Morris" jeffmo@NoSpam-sv-lokiDOTcom wrote in message ...
So perhaps you or Neal can explain to everyone how the horizontal beam width affect the
image.

-jeff

That's easy - here's a more complete answer than the other
one I just gave you.

Beam width is important in bearing resolution. All targets are widened by
the effective horizontal beam width. If the beam width is 4 degrees, two
targets that are one mile off will appear as one if they are closer together
than 370 feet. At two miles the targets must be separated by 740 feet, at 24
miles a six degree beam width would merge objects that were almost 1.68 miles
apart. This can make interpretation of the display difficult. Suppose you
are trying to find a harbor mouth that is 370 feet wide. Radar won't pick it
up until you get closer than a mile.

Get it?

S.Simon - a Captain who's a navigational phenom.

"Jeff Morris" jeffmo@NoSpam-sv-lokiDOTcom wrote in message ...
So perhaps you or Neal can explain to everyone how the horizontal beam width affect the
image.

-jeff


Capt. Mooron wrote:
Most people I've seen either find a radar image intuitively correct
to what they see around them ... or they don't. I knew immediately
what I was looking at on the first radar image I saw. I can
interpolate between radar, air photo and chart in an instant. I
mentally compensate for differences in scale and orientation. Maybe
I'm one of the lucky few... but I assumed everyone had this ability
to some extent.

CM

"Simple Simon" wrote in message
...

But radar is different from a paper chart because
a paper chart does not foreshorten the view while
radar does. Radar is really no different than a
looking at something with eyes that use radio
waves instead of light waves

Our eyes use light and when we see a hundred
yards of water at a distance of a quarter mile this
hundred yards of water looks a helluva lot shorter
than the same hundred yards right off our bow.

Radar 'sees' thing the same way so one must
extrapolate this information mentally in order
to match it with a chart of the same area.

It would be much the same as equating a gnomic
projection with a Mercator projection but backwards
if looking north on a Mercator.

See what I mean? But the point is the majority
of people can't even imagine such differences
let alone work with them.

This is what I mean by spatial comprehension.

S.Simon - a sailboat Captain who's superior to any and all motorboat
Captains

"Capt. Mooron" wrote in message
...
Generally I find that women are at a loss when it comes to spatial
comprehension. A man will usually automatically know the extended
limits of an automobile when he sits in one. Women depend on
mirrors and the visual depth of field at a specific spot to
determine this. This is one of the reasons why women generally do
not back into a parking space... while men prefer to. I say this is
a general trait.... I know of women who are very good with spatial
interpretation.

If you look at the radar screen as a chart... it is easier to
resolve the image and blend it to the area around you. Just keep in
mind that often you only view the proximal reflected surface of any
object. The "chart" on a radar screen is always oriented to the
line of the vessel and bearing is always relative unless a fluxgate
compass or GPS input is available. In a day or two I could easily
have you running with a full comprehension of radar... at least as
well as anyone else. Tuning radar is no problem....

CM

"Simple Simon" wrote in message
...


I've met many people who cannot extrapolate a land map
of an area they are familiar with much less be able to relate
to a nautical chart. If tests were given for this type of relating
a graphical representation to geography I bet you'd be
apalled at the numbers of folks who simply can't relate.

Bobsprit is probably one of these chart challenged people.

Simple things like basic orientation of the map while they
look at it leaves them at a loss. A radar display is even
more of an alien representation that a paper chart. Is the
display 'heads up' or "oriented north" for instance is more
than many people can cope with. Spatial relationships
and representative distances with respect to scale are
concepts many simply cannot fathom. I've only used
radar a couple of times and found it did not convey
much information at all other than skewed and foreshortened
spatial relationships that were difficult to stretch out into
geographical reality in my mind - a mind which excels
at spatiality.

I can see where practice, practice, practice and a mind
that can understand is vital for a radar operator. This is
yet another reason I think there should be a navigator at
the helm of large ships. Let the navigator navigator - let
the Captain steer according to input from the navigator.

S.Simon - a Captain who knows how things work




"Capt. Mooron" wrote in message
...

"Shen44" wrote in message

Radar is an aid to navigation, that is well learned if one has
one,
but
not as
important to learn for beginners, as some of the other basics,
such as compass, chart work, etc..
Contrary to what some may think, radar is not something you can
just
turn
on,
for the first time, and be instantly familiar and competent with
it's usage. I have seen any number of people using it on a
fairly regular
basis,
who
have
problems tuning (and sometimes detuning) for best picture, then
equating that picture to their charts or vessel traffic around
them.
Without knowing the basics of relative motion and how to plot
targets,
you
can
easily get yourself into as much trouble as you can avoid.

Maybe these people are the same ones with spatial difficulties. I
haven't seen anyone that has had a problem understanding a radar
image... tuning radar is a little more complicated ... but not
out of the realm of the newbie.

While I concur that Basic Navigation is primary obstacle to
overcome... a radar in use to confirm your plots and verify
relative bearings is perfectly fine.

The days of high tech being utilized only on large ships is over.
Navigational instrumentation is now available to the layman and
the general population's ability to embrace technology has
increased dramatically.

CM

On Tue, 02 Sep 2003 15:12:19 -0400, Simple Simon wrote:



That's easy - here's a more complete answer than the other one I just gave
you.

Beam width is important in bearing resolution. All targets are widened by
the effective horizontal beam width. If the beam width is 4 degrees, two
targets that are one mile off will appear as one if they are closer
together than 370 feet. At two miles the targets must be separated by 740
feet, at 24 miles a six degree beam width would merge objects that were
almost 1.68 miles apart. This can make interpretation of the display
difficult. Suppose you are trying to find a harbor mouth that is 370 feet
wide. Radar won't pick it up until you get closer than a mile.

Get it?

S.Simon - a Captain who's a navigational phenom.

LOL, cut & paste without attribution. Tsk, tsk. The source of the above:

http://lists.samurai.com/pipermail/t...il/010427.html

I'd never admit to reading a trawler site. . .

S.Simon

"thunder" wrote in message news

LOL, cut & paste without attribution. Tsk, tsk. The source of the above:

http://lists.samurai.com/pipermail/t...il/010427.html

Very good - I'm surprised CM didn't know this because its rather fundamental. Basically,
features will be wider on the screen by the beam width. "Inside" features, such as a cove
or entrance that are smaller than the beam width will disappear. Buoys that are closer
together than the beam width will merge. As you point out, RB wouldn't see the entrance
at Port Jeff until he's within a mile.

This is the real reason to get larger antennas, which have a smaller beam width.

BTW, where did you get your numbers? They correspond to statute miles. We use nautical
miles here, not baby miles.


Simple Simon wrote:
That's easy - here's a more complete answer than the other
one I just gave you.

Beam width is important in bearing resolution. All targets are
widened by
the effective horizontal beam width. If the beam width is 4 degrees,
two
targets that are one mile off will appear as one if they are closer
together
than 370 feet. At two miles the targets must be separated by 740
feet, at 24
miles a six degree beam width would merge objects that were almost
1.68 miles
apart. This can make interpretation of the display difficult.
Suppose you
are trying to find a harbor mouth that is 370 feet wide. Radar won't
pick it
up until you get closer than a mile.

Get it?

S.Simon - a Captain who's a navigational phenom.

"Jeff Morris" jeffmo@NoSpam-sv-lokiDOTcom wrote in message
...
So perhaps you or Neal can explain to everyone how the horizontal
beam width affect the image.

-jeff


Capt. Mooron wrote:
Most people I've seen either find a radar image intuitively correct
to what they see around them ... or they don't. I knew immediately
what I was looking at on the first radar image I saw. I can
interpolate between radar, air photo and chart in an instant. I
mentally compensate for differences in scale and orientation. Maybe
I'm one of the lucky few... but I assumed everyone had this ability
to some extent.

CM

"Simple Simon" wrote in message
...

But radar is different from a paper chart because
a paper chart does not foreshorten the view while
radar does. Radar is really no different than a
looking at something with eyes that use radio
waves instead of light waves

Our eyes use light and when we see a hundred
yards of water at a distance of a quarter mile this
hundred yards of water looks a helluva lot shorter
than the same hundred yards right off our bow.

Radar 'sees' thing the same way so one must
extrapolate this information mentally in order
to match it with a chart of the same area.

It would be much the same as equating a gnomic
projection with a Mercator projection but backwards
if looking north on a Mercator.

See what I mean? But the point is the majority
of people can't even imagine such differences
let alone work with them.

This is what I mean by spatial comprehension.

S.Simon - a sailboat Captain who's superior to any and all
motorboat Captains

"Capt. Mooron" wrote in message
...
Generally I find that women are at a loss when it comes to spatial
comprehension. A man will usually automatically know the extended
limits of an automobile when he sits in one. Women depend on
mirrors and the visual depth of field at a specific spot to
determine this. This is one of the reasons why women generally do
not back into a parking space... while men prefer to. I say this
is a general trait.... I know of women who are very good with
spatial interpretation.

If you look at the radar screen as a chart... it is easier to
resolve the image and blend it to the area around you. Just keep
in mind that often you only view the proximal reflected surface
of any object. The "chart" on a radar screen is always oriented
to the line of the vessel and bearing is always relative unless a
fluxgate compass or GPS input is available. In a day or two I
could easily have you running with a full comprehension of
radar... at least as well as anyone else. Tuning radar is no
problem....

CM

"Simple Simon" wrote in message
...


I've met many people who cannot extrapolate a land map
of an area they are familiar with much less be able to relate
to a nautical chart. If tests were given for this type of
relating a graphical representation to geography I bet you'd be
apalled at the numbers of folks who simply can't relate.

Bobsprit is probably one of these chart challenged people.

Simple things like basic orientation of the map while they
look at it leaves them at a loss. A radar display is even
more of an alien representation that a paper chart. Is the
display 'heads up' or "oriented north" for instance is more
than many people can cope with. Spatial relationships
and representative distances with respect to scale are
concepts many simply cannot fathom. I've only used
radar a couple of times and found it did not convey
much information at all other than skewed and foreshortened
spatial relationships that were difficult to stretch out into
geographical reality in my mind - a mind which excels
at spatiality.

I can see where practice, practice, practice and a mind
that can understand is vital for a radar operator. This is
yet another reason I think there should be a navigator at
the helm of large ships. Let the navigator navigator - let
the Captain steer according to input from the navigator.

S.Simon - a Captain who knows how things work




"Capt. Mooron" wrote in message
...

"Shen44" wrote in message

Radar is an aid to navigation, that is well learned if one has
one,
but
not as
important to learn for beginners, as some of the other basics,
such as compass, chart work, etc..
Contrary to what some may think, radar is not something you can
just
turn
on,
for the first time, and be instantly familiar and competent
with it's usage. I have seen any number of people using it on a
fairly regular
basis,
who
have
problems tuning (and sometimes detuning) for best picture, then
equating that picture to their charts or vessel traffic around
them.
Without knowing the basics of relative motion and how to plot
targets,
you
can
easily get yourself into as much trouble as you can avoid.

Maybe these people are the same ones with spatial difficulties.
I haven't seen anyone that has had a problem understanding a
radar image... tuning radar is a little more complicated ...
but not out of the realm of the newbie.

While I concur that Basic Navigation is primary obstacle to
overcome... a radar in use to confirm your plots and verify
relative bearings is perfectly fine.

The days of high tech being utilized only on large ships is
over. Navigational instrumentation is now available to the
layman and the general population's ability to embrace
technology has increased dramatically.

CM

BUSTED and caught in another lie!


Oh dear... he's wailing again.... I did not lie Bob!

So then prove it and show everyone what an honest man you are. Where is my post
where I said I can't read a radar?
While your at it, where is the post where i claimed to be sailing with no
charts?
Hmmmmmmm?

BUSTED!

RB