VOR and reverse sensing

"Casey Wilson" wrote:
In which case the VOR did NOT give you your position. The
calculation
required additional instruments: A timer and some device (compass
or DG) to
fly perpendicular to a radial, not to mention the use of the ASI,
and so
forth.

Silly hair splitting. You also said the VOR will give you bearing from
the station: how will it do that without the use of other equipment?
--
Dan
C172RG at BFM

"Casey Wilson" wrote in message
...
No, with one exception, it does not tell you your position. That
single
exception is when you overfly the antenna. Then, you may presume the
antenna
is some altitude dependent radius from the nadir. Otherwise, the only
thing
the VOR will tell you is BEARING from the station.

How is that not "position"? Granted, it's not a very accurate description
of one's position, but it certainly describes one's position to an extent.

Given that the word "position" is simply being used to contrast with
heading, course, and other related terms, your objection seems pretty silly
to me.

Pete

"Peter Duniho" wrote in message
...
"Casey Wilson" wrote in message
...
No, with one exception, it does not tell you your position. That
single
exception is when you overfly the antenna. Then, you may presume the
antenna
is some altitude dependent radius from the nadir. Otherwise, the only
thing
the VOR will tell you is BEARING from the station.

How is that not "position"? Granted, it's not a very accurate description
of one's position, but it certainly describes one's position to an extent.

Given that the word "position" is simply being used to contrast with
heading, course, and other related terms, your objection seems pretty
silly
to me.

Who is being silly? You are relating apples and oranges. Bearing is
related to heading and course, position is related to geographical
coordinates. A single VOR won't tell you squat about geographical
coordinates.
Given that the "standard service volume" (AIM 1-1-8) is at least 40
nautical miles, the definition is not a trivial thing. I have tuned into VOR
stations as much as 85 miles away. So, where am I on that line from the
station.
Let's consider that the acceptable angular error [ FAR 91.171(b)(3) ]
can be plus/minus 6 degrees. I don't have my calculator, but I think the
formula is cosine of the angle times the distance... I'm only guessing, but
I think that at the forty mile limit, the aircraft could be as much as five
to seven miles on either side of the displayed bearing angle. Hmm, let's
see: base times height divided by two [40 miles times 5 miles then divide by
2] gives 100 square miles. Wait, that was only the half-angle -- multiply
by two to cover the other side and we are up to 200 square miles of area
over which the airplane could be flying.
I like using the VOR, I like having two of them in the panel. Hell, I
even like the ADF -- got one of those too. When I triangulate any two of
those, I have a rough idea of my 'position.'

"Casey Wilson" wrote in message
...
Who is being silly? You are relating apples and oranges. Bearing is
related to heading and course, position is related to geographical
coordinates. A single VOR won't tell you squat about geographical
coordinates.

I have no idea what you're talking about.

Bearing relative to the VOR station is all about your position relative to
the station. Knowing your bearing relative to the station greatly narrows
down your geographical coordinates. You can get a lot more accurate using a
second VOR or DME, but that doesn't change the fact that even a single VOR
is telling you a lot about your geographical coordinates.

While on the other hand, the bearing relative to the VOR has NOTHING to do
with heading or course. Nothing at all. It boggles my mind that you would
say it does. The mistaken impression that it does have something to do with
heading or course is where lots of people (the original poster included) get
confused. You're just making matters worse by saying that it does.

Given that the "standard service volume" (AIM 1-1-8) is at least 40
nautical miles, the definition is not a trivial thing. I have tuned into
VOR
stations as much as 85 miles away. So, where am I on that line from the
station.

Just knowing you're on that line is useful GEOGRAPHICAL POSITION
information.

[...] and we are up to 200 square miles of area
over which the airplane could be flying.

All you're doing is bickering about just how accurate the GEOGRAPHICAL
POSITION information is. A single VOR isn't very accurate at all. Two VORs
are more accurate. A VOR with DME is even more accurate. Two VORs with DME
each are even more accurate. And a GPS receiver is even more accurate. So
what? They all still give you geographical positions.

I like using the VOR, I like having two of them in the panel. Hell, I
even like the ADF -- got one of those too. When I triangulate any two of
those, I have a rough idea of my 'position.'

No triangulation is needed to get a rough idea of your position.
Triangulation reduces the "roughness" of your position estimate, but a
single VOR receiver alone gives you a rough idea of your position. (An ADF,
of course, does no such thing...it MUST be referenced to another instrument
to provide ANY positional information at all).

Pete

Student here, following debate with interest but I don't understand the
issue at disagreement. Considering "bearing" as distinct from "relative
bearing", is not the bearing the clockwise angular direction with respect
to the meridian over its origin of a line drawn from one point to another?
And since the 0 radial of the VOR station is aligned to the magnetic
meridian, each VOR radial indicates directly the magnetic bearing from the
VOR station to an object that lies somewhere along it. To get one's bearing
from the VOR station, than, can you not just rotate the OBS until the needle
is centred? If the "from" flag is up then the OBS ring reads out directly
the magnetic bearing to the aircraft as viewed from the VOR station, and if
the "to" flag is up, the OBS is showing the reciprocal. So don't you know
you're somewhere along that line? Of course, neither indication gives the
actual aircraft position without using some other additional means to
establish distance from the station - DME, triangulation on another station,
etc. Same principle with a movable card ADF set to or slaved to one's
compass heading, except that its needle is always indicating the bearing to
whatever station that's tuned so one needs to convert that reading into the
radial bearing from the station of interest to the plane (I know that the
conversion assumes the magnetic variation at the plane's position is not
different from that at the station's position, if you want to get precise).

"Dan Luke" wrote in message
...
"Casey Wilson" wrote:
In which case the VOR did NOT give you your position. The
calculation
required additional instruments: A timer and some device (compass
or DG) to
fly perpendicular to a radial, not to mention the use of the ASI,
and so
forth.

Silly hair splitting. You also said the VOR will give you bearing from
the station: how will it do that without the use of other equipment?


--
Dan
C172RG at BFM

"Steve House" wrote in message
...
Student here, following debate with interest but I don't understand the
issue at disagreement. Considering "bearing" as distinct from "relative
bearing", is not the bearing the clockwise angular direction with respect
to the meridian over its origin of a line drawn from one point to another?
And since the 0 radial of the VOR station is aligned to the magnetic
meridian, each VOR radial indicates directly the magnetic bearing from the
VOR station to an object that lies somewhere along it. To get one's
bearing
from the VOR station, than, can you not just rotate the OBS until the
needle
is centred? If the "from" flag is up then the OBS ring reads out directly
the magnetic bearing to the aircraft as viewed from the VOR station, and
if
the "to" flag is up, the OBS is showing the reciprocal. So don't you know
you're somewhere along that line?

Yes. That was my point exactly. Only, somewhere along that line could
be anywhere within about a 200 square mile area when you factor in the
inherent accuracy of the single VOR.

Of course, neither indication gives the
actual aircraft position without using some other additional means to
establish distance from the station - DME, triangulation on another
station,
etc.

Yes. That was my point exactly.

"Peter Duniho"
*** I have no idea what you're talking about*****

In an unusual turn of events, the newsgroup idiot has spoken with some
knowledge. Peter has no clue since his head has been up his ass for so long
it's stuck there.

Knowing the radial one is on is only half the position formula. Position is
a vector quantity. Knowing your radial is a scalar quantity and distance is
needed to provide the vector quantity, position.

*****No triangulation is needed to get a rough idea of your position.
Triangulation reduces the "roughness" of your position estimate, but a
single VOR receiver alone gives you a rough idea of your position. (An
ADF,*****

Were you asleep in basic algebra, Peter? As you certainly were in private
pilot ground school. Peter, you are so easy to pigeon hole. Too bad aviation
has become such an easy place for fat ass know it alls to flop.

http://www.sasked.gov.sk.ca/docs/physics/u1b3phy.html


Karl

"Jeffrey Voight" wrote in message ...

Using your rule, I wouldn't be able to take a position fix without
turning the plane.

I didn't say that, I was refering to flying the VOR. I was specifically countering
your statement that you only use the FROM flag when you are trying to hunt
the radial.

You need to get less emotional about mnenomics

I'm not emotional, I'm just trying to avoid getting prosepective students all
messed up with your bizarre incorrect information.

"Robert Perkins" wrote in message ...


Not if you use the VOR as an instrument to help you with magnetic
headings, relying on the compass or DH for that data, rather than as a
command instrument.

You're going to sit there spinning the needle all the time to figure out what
radial you are on. Then you're going to look at the compass to figure out
if you are left or right of the course and turn that way, and then continually
recenter the needle to see what change that made?

No sane person flies the VOR that way. The needle isn't the command instrument,
but it tells you which side of the course you are, you then apply a currention to
the heading (turn towards the needle) and fly it using your primary heading
reference.

On Mon, 18 Aug 2003 10:06:10 -0400, "Ron Natalie"
wrote:


"Robert Perkins" wrote in message ...


Not if you use the VOR as an instrument to help you with magnetic
headings, relying on the compass or DH for that data, rather than as a
command instrument.

You're going to sit there spinning the needle all the time to figure out what
radial you are on.

No, you're going to spin the needle once until you've centered it and
the thing says "FROM". Then you know what radial you're on, and you
can use the needle to choose headings to intercept the radial.

Regarding position, it's true that one VOR won't tell you your exact
position. But if you combine pilotage from a chart with the relative
position data ("southeast of the station", "west of the station",
whatever.), you will have your position.

And in ANY case, what prevents the one-VOR-equipped pilot from flying
a standard-rate turn and tuning first one VOR for a fix, and then a
second for another fix, thus establishing his position very
accurately?

Gawrsh, maybe I really ought to go get that instrument rating... ;-)

Then you're going to look at the compass to figure out
if you are left or right of the course and turn that way, and then continually
recenter the needle to see what change that made?

No! That's madness. I'm not going to recenter the needle at all; I'm
going to fly a heading for two minutes and take a second reading from
the VOR, and not ever use the needle to steer the airplane unless I'm
flying right to the station.

Rob