Not one of the Numb-Nutted gNomes of kNighted Nowhere came up with any issue
related to how RDF works or why its accuracy was rather great than two degree.

They did flail away at the wind while chasing their stubby tails.

That's because in two days ago not one of them had even google knowledge of the
subject, and even today not one of them understands even the basics.

Tomorrow you will see more Tasmanian Devil whirling from the clowns as to how
and why RDF works.

two days ago they were ignorant. Today they are amateurs. Tomorrow they are
fools.

.....And you haven't come up with one fact to say it can't be better than 2
degrees, other than some dumb comparison to taking a bearing on sounds (a known
no-no), and have shown you don't know the basics of piloting, when using a
compass.

Shen

shen, think about it for a minute. *Just ONE* of the issues is that a radio
compass is aligned using a magnetic compass.

think about it? how many mag compasses have seen on boats that are accurate to
2*?

Think about it more. How many helmsmen on sailboats have you seen that could
hold a course to 2* over any period of time?

Think about it. the error of the mag compass reading TIMES the error of the
helmsman gives the potential error UP TO THAT POINT. Already, you are
waaaaaaaaaay beyond 2*. waaaaaaaaaaaaaaay beyond.

Think about the additional errors associated with just the radio compass itself
and its usage.

think about it, shen.

Think.

....And you haven't come up with one fact to say it can't be better than 2
degrees, other than some dumb comparison to taking a bearing on sounds (a
known
no-no), and have shown you don't know the basics of piloting, when using a
compass.

Shen

JAXAshby wrote:


Think about it. the error of the mag compass reading TIMES the error of the
helmsman gives the potential error UP TO THAT POINT.

Wrong.

Cheers
Marty

oh? errors don't multiply?

What an interesting concept. Where did you learn that? From a bubble gum
wrapper?


Think about it. the error of the mag compass reading TIMES the error of
the
helmsman gives the potential error UP TO THAT POINT.

Wrong.

Cheers
Marty

Jaxie, how many stupid things can you say in one post. Magnetic compasses can
certainly be accurate to 2 degrees, though I admit nowadays a lot of people
don't bother to swing the compass, what with GPS and autopilots, but in the old
days it was pretty common to have it professional done, and to check it with
known ranges at every opportunity.

Holding a course to 2 degrees may be difficult for a long period, but for the
short time needed for a bearing is not too hard.

And errors multiply??? That's one of the stupidest things you ever come out
with jaxie! Are you claiming that a 5 degree compass error and a 5 degree
course error yield a net 25 degree error??? I think that one's another keeper!

And why does RDF calibration depend on the ship's compass? There are others
ways to check for deviation that don't depend on the compass.

"JAXAshby" wrote in message
...
shen, think about it for a minute. *Just ONE* of the issues is that a radio
compass is aligned using a magnetic compass.

think about it? how many mag compasses have seen on boats that are accurate
to
2*?

Think about it more. How many helmsmen on sailboats have you seen that could
hold a course to 2* over any period of time?

Think about it. the error of the mag compass reading TIMES the error of the
helmsman gives the potential error UP TO THAT POINT. Already, you are
waaaaaaaaaay beyond 2*. waaaaaaaaaaaaaaay beyond.

Think about the additional errors associated with just the radio compass
itself
and its usage.

think about it, shen.

Think.

....And you haven't come up with one fact to say it can't be better than 2
degrees, other than some dumb comparison to taking a bearing on sounds (a
known
no-no), and have shown you don't know the basics of piloting, when using a
compass.

Shen

Subject: Not one person
From: (JAXAshby)

shen, think about it for a minute. *Just ONE* of the issues is that a radio
compass is aligned using a magnetic compass.

Not exclusively, but you knew that.
So we're sure (you tend towards weird associations), you do mean that the
(usually, on small boats) relative bearing taken from the RDF is added or
subtracted, as the case may be, to the compass heading which is corrected to
magnetic bearing or to true bearing, prior to ploting?
Silly me, that's a question.


think about it? how many mag compasses have seen on boats that are accurate
to
2*?

Quite a few.


Think about it more. How many helmsmen on sailboats have you seen that could
hold a course to 2* over any period of time?

Quite a few


Think about it. the error of the mag compass reading TIMES the error of the
helmsman gives the potential error UP TO THAT POINT. Already, you are
waaaaaaaaaay beyond 2*. waaaaaaaaaaaaaaay beyond.

You still haven't learned to use a compass for navigation, I see.
Times or plus, doesn't matter.
However, while following this thread it's become obvious that this is probably
the best you could do.


Think about the additional errors associated with just the radio compass
itself
and its usage.

I see your reading is progressing.


think about it, shen.

I have. Your biggest problems revolve around the facts that you only know what
you read, and have little if any understanding of the everyday "nuts and
bolts".
To continue to add to the list:
You don't know how to steer.
You don't know how to take bearings.
etc.

Shen

jeffies, one at a time

Magnetic compasses can
certainly be accurate to 2 degrees,

we were discussing recreational sailboats here, so let's stay with the magnetic
compasses one would find on such.

but in the
old
days it was pretty common to have it professional done, and to check it with
known ranges at every opportunity.

and read by an amateur in a moving boat under at sea conditions. and how many
compasses on the boats under discussion could *you* read to 2* or even 5*?

All of them right, because you read it in a book.

until this very minute you didn't know that a compass rotates one way as th
boat goes up a wave and rotates the other way going down a wave. Same thing as
the boat rolls one way and then the other.


Holding a course to 2 degrees may be difficult for a long period, but for the
short time needed for a bearing is not too hard.

ever helmed a boat, jeffies?


And errors multiply??? That's one of the stupidest things you ever come out
with jaxie! Are you claiming that a 5 degree compass error and a 5 degree
course error yield a net 25 degree error??? I think that one's another
keeper!

jeffies, you stupid cluck. YOU claim to have a degree in physics (okay, an
arts degree and from Potato State), and if you were even qualified to take
freshman courses in the subject you wouldn't make such a dumb statement.

So, let's start by admiting you lied about what you know and what you should
know.

Then, consider this, jeffies. why is it you think a 2* error here and a 5*
error that makes for a 3* to 7* total? It does not.

Now follow this. I'll use % of error rather than * because it makes it easier
for a rank beginner math person like you.

a 2% error means the actual might be anywhere from 98% to 102%. Understand?

Now bring on the next error, of 5%. you do NOT take the 5% error against the
original 100% but rather against the 98% to 102%.

THIS MEANS you take 95% to 105% against the errored 98% to 102%. Giving you a
potential error of 0.95 times 0.98, or just over 93% on the lower side and 1.02
times 1.05 or just over 7% on the upper side.

The incremental error is small in this case because the original errors were
small AND there were just two errors to cascade. EACH succeding error is
MULTIPLIED by the total of the previous errors. A string of four or five
errors, each small, can make for a highly uncertain result.

In the case of the radio compass, yo have the error of reading the mag compass
by the helmsman, the error of maybe forgeting variation, the error in the
compass, the error of maybe local deviation, the error of the compassman in
placing the compass, the error of the helmsman in holding course, the error in
the compassman's listening to and hearding the nullness of the signal, the
error of alignment of the compass dial with the antenna, and the error of
reading the dial after the reading was taken.

Now, you HAVE AT LEAST TWO READINGS to take, *****each**** with potential
errors above.

In addition, you have the error of the boat movement, which can only be
estimated (no gps onboard, remember?)

In addition, you have more -- and potentially large -- errors if the two read
stations at not at right angles to the boat.

And why does RDF calibration depend on the ship's compass? There are others
ways to check for deviation that don't depend on the compass.

the discussion was a recreational sailboat.


"JAXAshby" wrote in message
...
shen, think about it for a minute. *Just ONE* of the issues is that a
radio
compass is aligned using a magnetic compass.

think about it? how many mag compasses have seen on boats that are
accurate
to
2*?

Think about it more. How many helmsmen on sailboats have you seen that
could
hold a course to 2* over any period of time?

Think about it. the error of the mag compass reading TIMES the error of
the
helmsman gives the potential error UP TO THAT POINT. Already, you are
waaaaaaaaaay beyond 2*. waaaaaaaaaaaaaaay beyond.

Think about the additional errors associated with just the radio compass
itself
and its usage.

think about it, shen.

Think.

....And you haven't come up with one fact to say it can't be better than 2
degrees, other than some dumb comparison to taking a bearing on sounds (a
known
no-no), and have shown you don't know the basics of piloting, when using a
compass.

Shen

you are right. it is a silly question.

shen, think about it. ******How******* did the radio compass get aligned?
duh.

shen, think about it for a minute. *Just ONE* of the issues is that a radio
compass is aligned using a magnetic compass.

Not exclusively, but you knew that.
So we're sure (you tend towards weird associations), you do mean that the
(usually, on small boats) relative bearing taken from the RDF is added or
subtracted, as the case may be, to the compass heading which is corrected to
magnetic bearing or to true bearing, prior to ploting?
Silly me, that's a question.


think about it? how many mag compasses have seen on boats that are accurate
to
2*?

Quite a few.


Think about it more. How many helmsmen on sailboats have you seen that
could
hold a course to 2* over any period of time?

Quite a few


Think about it. the error of the mag compass reading TIMES the error of the
helmsman gives the potential error UP TO THAT POINT. Already, you are
waaaaaaaaaay beyond 2*. waaaaaaaaaaaaaaay beyond.

You still haven't learned to use a compass for navigation, I see.
Times or plus, doesn't matter.
However, while following this thread it's become obvious that this is
probably
the best you could do.


Think about the additional errors associated with just the radio compass
itself
and its usage.

I see your reading is progressing.


think about it, shen.

I have. Your biggest problems revolve around the facts that you only know
what
you read, and have little if any understanding of the everyday "nuts and
bolts".
To continue to add to the list:
You don't know how to steer.
You don't know how to take bearings.
etc.

Shen

Jeff Morris wrote:
Jaxie, how many stupid things can you say in one post. Magnetic compasses can
certainly be accurate to 2 degrees, though I admit nowadays a lot of people
don't bother to swing the compass, what with GPS and autopilots, but in the old
days it was pretty common to have it professional done, and to check it with
known ranges at every opportunity.

I'd still recommend checking it against known ranges, even if only to
confirm the veracity of your deviation tables/scale.

Holding a course to 2 degrees may be difficult for a long period, but for the
short time needed for a bearing is not too hard.

Too true, but Jax can't steer .... probably chases the compass.

And errors multiply??? That's one of the stupidest things you ever come out
with jaxie! Are you claiming that a 5 degree compass error and a 5 degree
course error yield a net 25 degree error??? I think that one's another keeper!

One must never question Jax's reasoning .... accept the fact it's off
the wall.


And why does RDF calibration depend on the ship's compass? There are others
ways to check for deviation that don't depend on the compass.

I think he's just getting to this part in his reading. He wasn't talking
about "calibration", he was talking about converting the relative RDF
bearing to compass bearing to magnetic bearing, so it could be plotted
..... at least, I think that's what his "align" means.
Not knowing much or having done much navigation, Jax tends use terms
that most of us wouldn't, so it sometimes takes a bit to figure how he's
applying those terms.

otn