I was wondering how to program this into the 430, and if it is even
possible. Say you are east of a VOR and ATC gives you a vector to
intercept the 270 radial FROM the VOR and track away from the VOR on
that radial and intercept an airway. The clearance went something
like this:

"Glasair 470XX, fly heading 220, intercept and fly the PDZ 270 to
intercept V394."

Since GPS navigation is TO-TO, how could I get the magenta line on the
screen to be on the 270 radial from the VOR? I guess I could put in
the PDZ VOR as a direct waypoint, then use the OBS button on the 430
and the OBS ring on the VOR head rotate the magenta line drawn from my
present postion to the VOR to rotate and align to the 270 radial. I
would have to set the OBS to 090. That would get the line on the
screen, but I would be flying to the VOR not from it.

How can I do this? BTW, there is no published intersect on V394 that
I am intercepting in this clearance, so I cannot select that waypoint
and fly 270 to it.

Maybe ATC should stop giving these types of clearances and just say
"fly heading 270 and intercept V394".

> wrote in message
...
>I was wondering how to program this into the 430, and if it is even
> possible. Say you are east of a VOR and ATC gives you a vector to
> intercept the 270 radial FROM the VOR and track away from the VOR on
> that radial and intercept an airway. The clearance went something
> like this:
>
> "Glasair 470XX, fly heading 220, intercept and fly the PDZ 270 to
> intercept V394."
>
> Since GPS navigation is TO-TO, how could I get the magenta line on the
> screen to be on the 270 radial from the VOR? I guess I could put in
> the PDZ VOR as a direct waypoint, then use the OBS button on the 430
> and the OBS ring on the VOR head rotate the magenta line drawn from my
> present postion to the VOR to rotate and align to the 270 radial. I
> would have to set the OBS to 090. That would get the line on the
> screen, but I would be flying to the VOR not from it.
>
> How can I do this? BTW, there is no published intersect on V394 that
> I am intercepting in this clearance, so I cannot select that waypoint
> and fly 270 to it.
>
> Maybe ATC should stop giving these types of clearances and just say
> "fly heading 270 and intercept V394".

I don't have the 430, but you should be able to enter a flight plan with
PDZ-V394, push the OBS button and dial in 270. You just might have to fly
the white line instead of the magenta line (assuming the 430 gives you a
white line on the 270 radial and I think it should).

Alternatively you can always just use the NAV receiver, dial in the VOR's
frequency, and do it the old fashioned way which is what I generally do.

ATC is not going to stop giving radial intercepts anytime soon. The
difference between the clearance you got and the clearance you suggested is
ATC knows within reason what path you are going to be on when they put you
on the radial. If they just gave you a vector, they might have to revector
you at a later time which is more work for them. It also makes handoffs
easier as you're flying a known path.

Mike wrote:
> > wrote in message
> ...
>
>> I was wondering how to program this into the 430, and if it is even
>> possible. Say you are east of a VOR and ATC gives you a vector to
>> intercept the 270 radial FROM the VOR and track away from the VOR on
>> that radial and intercept an airway. The clearance went something
>> like this:
>>
>> "Glasair 470XX, fly heading 220, intercept and fly the PDZ 270 to
>> intercept V394."
>>
>> Since GPS navigation is TO-TO, how could I get the magenta line on the
>> screen to be on the 270 radial from the VOR? I guess I could put in
>> the PDZ VOR as a direct waypoint, then use the OBS button on the 430
>> and the OBS ring on the VOR head rotate the magenta line drawn from my
>> present postion to the VOR to rotate and align to the 270 radial. I
>> would have to set the OBS to 090. That would get the line on the
>> screen, but I would be flying to the VOR not from it.
>>
>> How can I do this? BTW, there is no published intersect on V394 that
>> I am intercepting in this clearance, so I cannot select that waypoint
>> and fly 270 to it.
>>
>> Maybe ATC should stop giving these types of clearances and just say
>> "fly heading 270 and intercept V394".
>
>
> I don't have the 430, but you should be able to enter a flight plan with
> PDZ-V394, push the OBS button and dial in 270. You just might have to
> fly the white line instead of the magenta line (assuming the 430 gives
> you a white line on the 270 radial and I think it should).
>
The 430 doesn't have airways. With two 430s this would be easy, using
the OBS function on both. With one 430 I would do as you suggest, set
up the PDZ 270 radial in OBS mode, intercept it, establish a track, then
continue to fly the heading that holds the track, and switch to POM with
the OBS set at 358.

The trick is to remember to turn off OBS before you wonder off past POM
in this case. I don't know about other panel mounts but the Garmin
400/500 retain the course set in OBS mode after you release OBS,
provided you don't do anything else that would modify the course. And,
as you say, you may have to fly the white line instead of the magenta
line sometimes, but that works, at least in heading mode or hand flying.

Am I missing something here?

What godly difference could it make whether you track a magenta,
white, or fuschia line on a GPS screen, or have the OBS set to 90 or
270?

It's all the same course over the ground...




On Sat, 12 Jul 2008 01:26:21 -0700, Sam Spade >
wrote:

>Mike wrote:
>> > wrote in message
>> ...
>>
>>> I was wondering how to program this into the 430, and if it is even
>>> possible. Say you are east of a VOR and ATC gives you a vector to
>>> intercept the 270 radial FROM the VOR and track away from the VOR on
>>> that radial and intercept an airway. The clearance went something
>>> like this:
>>>
>>> "Glasair 470XX, fly heading 220, intercept and fly the PDZ 270 to
>>> intercept V394."
>>>
>>> Since GPS navigation is TO-TO, how could I get the magenta line on the
>>> screen to be on the 270 radial from the VOR? I guess I could put in
>>> the PDZ VOR as a direct waypoint, then use the OBS button on the 430
>>> and the OBS ring on the VOR head rotate the magenta line drawn from my
>>> present postion to the VOR to rotate and align to the 270 radial. I
>>> would have to set the OBS to 090. That would get the line on the
>>> screen, but I would be flying to the VOR not from it.
>>>
>>> How can I do this? BTW, there is no published intersect on V394 that
>>> I am intercepting in this clearance, so I cannot select that waypoint
>>> and fly 270 to it.
>>>
>>> Maybe ATC should stop giving these types of clearances and just say
>>> "fly heading 270 and intercept V394".
>>
>>
>> I don't have the 430, but you should be able to enter a flight plan with
>> PDZ-V394, push the OBS button and dial in 270. You just might have to
>> fly the white line instead of the magenta line (assuming the 430 gives
>> you a white line on the 270 radial and I think it should).
>>
>The 430 doesn't have airways. With two 430s this would be easy, using
>the OBS function on both. With one 430 I would do as you suggest, set
>up the PDZ 270 radial in OBS mode, intercept it, establish a track, then
>continue to fly the heading that holds the track, and switch to POM with
>the OBS set at 358.
>
>The trick is to remember to turn off OBS before you wonder off past POM
>in this case. I don't know about other panel mounts but the Garmin
>400/500 retain the course set in OBS mode after you release OBS,
>provided you don't do anything else that would modify the course. And,
>as you say, you may have to fly the white line instead of the magenta
>line sometimes, but that works, at least in heading mode or hand flying.

Les Izmore wrote:
> Am I missing something here?
>
> What godly difference could it make whether you track a magenta,
> white, or fuschia line on a GPS screen, or have the OBS set to 90 or
> 270?

It does so long as you are hand flying or using heading mode. Some
autopilots won't understand it in some cases though.

Like flying a back course perhaps?

On Jul 12, 6:05*am, Sam Spade > wrote:
> Les Izmore wrote:
> > Am I missing something here?
>
> > What godly difference could it make whether you track a magenta,
> > white, or fuschia line on a GPS screen, or have the OBS set to 90 or
> > 270?
>
> It does so long as you are hand flying or using heading mode. *Some
> autopilots won't understand it in some cases though.
>
> Like flying a back course perhaps?

Exactly, since you set 090 on the OBS but you are flying 270, you are
going 180 degrees
in the "wrong" direction on the bearing TO the VOR. You are flying
FROM. Off course, the
autopilot or GPSS will try to turn you all the way around.

If you know that you will get this clearance, you would have to creat a user
waypoint using the radial 187 from POM (i.e. V394) and the PDZ 270 radial.
You can title the waypoint "PD270" or something and simply insert it into
your flight plan. The flight plan would then be:

PDZ
PD270
AHEIM

When you create the user waypoint, you will notice that you can leave the
distance field blank and define the waypoint by two different radials. I
tried it on the 430 simulator and it seems to be doing what you hope to
accomplish.

Marco


> wrote in message
...
>I was wondering how to program this into the 430, and if it is even
> possible. Say you are east of a VOR and ATC gives you a vector to
> intercept the 270 radial FROM the VOR and track away from the VOR on
> that radial and intercept an airway. The clearance went something
> like this:
>
> "Glasair 470XX, fly heading 220, intercept and fly the PDZ 270 to
> intercept V394."
>
> Since GPS navigation is TO-TO, how could I get the magenta line on the
> screen to be on the 270 radial from the VOR? I guess I could put in
> the PDZ VOR as a direct waypoint, then use the OBS button on the 430
> and the OBS ring on the VOR head rotate the magenta line drawn from my
> present postion to the VOR to rotate and align to the 270 radial. I
> would have to set the OBS to 090. That would get the line on the
> screen, but I would be flying to the VOR not from it.
>
> How can I do this? BTW, there is no published intersect on V394 that
> I am intercepting in this clearance, so I cannot select that waypoint
> and fly 270 to it.
>
> Maybe ATC should stop giving these types of clearances and just say
> "fly heading 270 and intercept V394".
>
>

On Sat, 12 Jul 2008 06:05:28 -0700, Sam Spade >
wrote:

>Les Izmore wrote:
>> Am I missing something here?
>>
>> What godly difference could it make whether you track a magenta,
>> white, or fuschia line on a GPS screen, or have the OBS set to 90 or
>> 270?
>
>It does so long as you are hand flying or using heading mode. Some
>autopilots won't understand it in some cases though.
>
>Like flying a back course perhaps?


Those inflatable things that smile while they are being inflated?

Never use them.

Marco Leon wrote:
> If you know that you will get this clearance, you would have to creat a user
> waypoint using the radial 187 from POM (i.e. V394) and the PDZ 270 radial.
> You can title the waypoint "PD270" or something and simply insert it into
> your flight plan. The flight plan would then be:
>
> PDZ
> PD270
> AHEIM
>
> When you create the user waypoint, you will notice that you can leave the
> distance field blank and define the waypoint by two different radials. I
> tried it on the 430 simulator and it seems to be doing what you hope to
> accomplish.
>
> Marco

Would you explain how you creat a user waypoint using two radials as
opposed to a radial and distance?

Sam Spade wrote:
> Marco Leon wrote:
>> If you know that you will get this clearance, you would have to creat
>> a user waypoint using the radial 187 from POM (i.e. V394) and the PDZ
>> 270 radial. You can title the waypoint "PD270" or something and simply
>> insert it into your flight plan. The flight plan would then be:
>>
>> PDZ
>> PD270
>> AHEIM
>>
>> When you create the user waypoint, you will notice that you can leave
>> the distance field blank and define the waypoint by two different
>> radials. I tried it on the 430 simulator and it seems to be doing what
>> you hope to accomplish.
>>
>> Marco
>
> Would you explain how you creat a user waypoint using two radials as
> opposed to a radial and distance?
I have a 530W but expect the 430 would do the same. On Page 135 of the
manual it says you can do what Marco says. There is a line for Ref Wpt,
RADial and DIS. Leave distance blank

Next line allows entry of another waypoint (e.g. vor) with blank for Radial.

Works fine.

BillJ wrote:
> Sam Spade wrote:
>
>> Marco Leon wrote:
>>
>>> If you know that you will get this clearance, you would have to creat
>>> a user waypoint using the radial 187 from POM (i.e. V394) and the PDZ
>>> 270 radial. You can title the waypoint "PD270" or something and
>>> simply insert it into your flight plan. The flight plan would then be:
>>>
>>> PDZ
>>> PD270
>>> AHEIM
>>>
>>> When you create the user waypoint, you will notice that you can leave
>>> the distance field blank and define the waypoint by two different
>>> radials. I tried it on the 430 simulator and it seems to be doing
>>> what you hope to accomplish.
>>>
>>> Marco
>>
>>
>> Would you explain how you creat a user waypoint using two radials as
>> opposed to a radial and distance?
>
> I have a 530W but expect the 430 would do the same. On Page 135 of the
> manual it says you can do what Marco says. There is a line for Ref Wpt,
> RADial and DIS. Leave distance blank
>
> Next line allows entry of another waypoint (e.g. vor) with blank for
> Radial.
>
> Works fine.

Have you actually tried this with your 530W?

It does not work in the 530 trainer.

I verified that it works in both the 430 and 430W trainer. I can't imagine
the 530 trainer(s) would be programmed with different logic than the 430's.
As a shortcut, you can insert the user waypoint name (as long as it is
unique--in my example it was "PD270") in the desired spot in your flight
plan and the unit will prompt you whether or not you would like to create a
user waypoint. After pressing YES, it will take you to the user waypoint
creation page.

Once you hit ENT, the unit will fill in the distance value automatically
since it already has two datapoints.

Hope this helps.

Marco

wrote:
> I verified that it works in both the 430 and 430W trainer. I can't imagine
> the 530 trainer(s) would be programmed with different logic than the 430's.
> As a shortcut, you can insert the user waypoint name (as long as it is
> unique--in my example it was "PD270") in the desired spot in your flight
> plan and the unit will prompt you whether or not you would like to create a
> user waypoint. After pressing YES, it will take you to the user waypoint
> creation page.
>
> Once you hit ENT, the unit will fill in the distance value automatically
> since it already has two datapoints.
>
> Hope this helps.
>
> Marco

I am familar with that method of creating a user waypoint; i.e., add it
to the active flight plan with a unique name. And, then a LAT/LON can
be entered or a radial/distance from an existing waypoint. And, I
understand there is a second reference facility without distance on the
waypoint data page.

But, I cannot accomplish a radial/radial waypoint nor can I find it
documented in the Garmin 530 pilot's manual.

Let me provide an example of what I am trying to accomplish and you tell
me how you would do this one.

Let's name the waypoint POM13

The waypoing I want to create is where V-264 intersects V-137 east of
POM VOR (more precisely on V-264 east of REANS and west of YUCCA.)

The FAA lists all such airway intersections in its airways database.
The following is an excerpt from the NACO data file for V-137 between
PSP and PMD:

PSP PSP 33 52 12.1 116 25 47.2 ZLA -13 VORTAC

WHETO WHETO 33 57 27.9 116 36 51.2 ZLA RPRT PT

MORON MORON 34 02 00.8 116 46 27.7 ZLA RPRT PT

V264 15419 34 05 49.9 116 54 33.8 ZLA AWY INT

V283 21527 34 11 50.8 117 07 23.2 ZLA AWY INT

ARRAN ARRAN 34 13 07.6 117 10 08.3 ZLA RPRT PT
V442 22186 34 17 04.0 117 18 34.9 ZLA
AWY INT
HITOP HITOP 34 17 58.7 117 20 33.2 ZLA RPRT PT

HESPE HESPE 34 20 28.2 117 25 55.3 ZLA RPRT PT

PMD PMD 34 37 53.0 118 03 49.8 ZLA -15 VORTAC


The user waypoint you say you can create should be:

34 05 49.9 116 54 33.8, which is shown as "15149" in the FAA's database.

So, this would be the POM 073 radial and the PSP 287 radial. Could you
tell me how you enter those two facilities and radials and ignore the
distance field for the first reference waypoint?

Thanks

wrote:
> I verified that it works in both the 430 and 430W trainer. I can't imagine
> the 530 trainer(s) would be programmed with different logic than the 430's.
> As a shortcut, you can insert the user waypoint name (as long as it is
> unique--in my example it was "PD270") in the desired spot in your flight
> plan and the unit will prompt you whether or not you would like to create a
> user waypoint. After pressing YES, it will take you to the user waypoint
> creation page.
>
> Once you hit ENT, the unit will fill in the distance value automatically
> since it already has two datapoints.
>
> Hope this helps.
>
> Marco


You got me wondering whether the 530W did user waypoints differently, so
I downloaded the 530W manual.


Page 136:

"To create a new user waypoint by entering its latitude/longitude position"

Page 137:

"To create a new user waypoint by referencing an existing waypoint"
This procedure uses radial/distance from the existing waypoing.

Page 138:

"Creating User Waypoints from the Map Page"

Also on Page 138:

"To capture and save your present position as a user waypoint"

Page 139:

Two options for modifying an existing user waypoint:

"From the User Waypoint Page, use the small and large right knobs to
modify the position coordinates of an existing user waypoint."

"You can modify the location of an exist-ing waypoint by changing the
reference waypoint and/or by changing the radial and distance"

Finally, Page 140:

"With the radial (RAD) field highlighted, use the small and large right
knobs to enter a new radial from the reference waypoint"

There is nothing on any of these pages about how to create a user
waypoint using the intersection of two radials.

"Sam Spade" > wrote in message
...

> You got me wondering whether the 530W did user waypoints differently, so I
> downloaded the 530W manual.
>
>
> Page 136:
>
> "To create a new user waypoint by entering its latitude/longitude
> position"
>
> Page 137:
>
> "To create a new user waypoint by referencing an existing waypoint" This
> procedure uses radial/distance from the existing waypoing.

This is the page on 137. The manual is probably referring to a VOR as a
waypoint. #4 states: "Use the small and large right knobs to enter the
identifier of the reference waypoint. The reference waypoint can be an
airport, VOR, NDB, intersection or another user waypoint. Press ENT to
accept the selected identifier."

If you look at the note in the next column on page 137 it states, " The
second reference waypoint field (REF WPT) is a temporary reference only -
not a reference that is stored with the user waypoint. You may also use this
in conjunction with the first reference waypoint to create a position using
the intersection of two radials."

Marco

Marco Leon wrote:
> "Sam Spade" > wrote in message
> ...
>
>
>>You got me wondering whether the 530W did user waypoints differently, so I
>>downloaded the 530W manual.
>>
>>
>>Page 136:
>>
>>"To create a new user waypoint by entering its latitude/longitude
>>position"
>>
>>Page 137:
>>
>>"To create a new user waypoint by referencing an existing waypoint" This
>>procedure uses radial/distance from the existing waypoing.
>
>
> This is the page on 137. The manual is probably referring to a VOR as a
> waypoint. #4 states: "Use the small and large right knobs to enter the
> identifier of the reference waypoint. The reference waypoint can be an
> airport, VOR, NDB, intersection or another user waypoint. Press ENT to
> accept the selected identifier."
>
> If you look at the note in the next column on page 137 it states, " The
> second reference waypoint field (REF WPT) is a temporary reference only -
> not a reference that is stored with the user waypoint. You may also use this
> in conjunction with the first reference waypoint to create a position using
> the intersection of two radials."
>
> Marco
>
>

I missed that note. But, that note is somewhat different in the 530
manual because not reference is made to creating a position using the
intersection of two radials.

So apparently this radial/radial option was a new feature in the WAAS
series.

"Sam Spade" > wrote in message
...
> Marco Leon wrote:
> I missed that note. But, that note is somewhat different in the 530
> manual because not reference is made to creating a position using the
> intersection of two radials.
>
> So apparently this radial/radial option was a new feature in the WAAS
> series.

The functionality is in the 530 (A) but it's not explicitly stated in the
old manual. There is a note in that section but the statement about using
two radials to create a user waypoint is not there.

Marco

Marco Leon wrote:
> "Sam Spade" > wrote in message
> ...
>
>>Marco Leon wrote:
>>I missed that note. But, that note is somewhat different in the 530
>>manual because not reference is made to creating a position using the
>>intersection of two radials.
>>
>>So apparently this radial/radial option was a new feature in the WAAS
>>series.
>
>
> The functionality is in the 530 (A) but it's not explicitly stated in the
> old manual. There is a note in that section but the statement about using
> two radials to create a user waypoint is not there.
>
> Marco
>
>
Thanks for your help.

Indeed it does work in the 530 trainer. I guess I was hung up on the
reference waypoint changing after I created the intersection. The
handbook says that doesn't matter, which of course it doesn't. ;-)

The 530 and the 530W created a slightly different position for the
intersection of V-264 and V-137.

And, the official FAA position is slightly different than those two.
The difference is reasonable for an en route airway intersection. I
wouldn't want to be designing IAPs using this method, though. ;-)

Intersection of V-264 and V137:

FAA:

34 05 49.9
116 54 33.8


530:

34 06 02.0
116 54 50.7


530W:

34 06 01.9
116 54 50.2

It would be interesting to construct this waypoint at a location with a
different mag var than the location I used and see if that would affect
the device's calculation. Next time.

Sam Spade wrote:
> Marco Leon wrote:
>
>> "Sam Spade" > wrote in message
>> ...
>>
>>> Marco Leon wrote:
>>> I missed that note. But, that note is somewhat different in the 530
>>> manual because not reference is made to creating a position using the
>>> intersection of two radials.
>>>
>>> So apparently this radial/radial option was a new feature in the WAAS
>>> series.
>>
>>
>>
>> The functionality is in the 530 (A) but it's not explicitly stated in
>> the old manual. There is a note in that section but the statement
>> about using two radials to create a user waypoint is not there.
>>
>> Marco
>>
> Thanks for your help.
>
> Indeed it does work in the 530 trainer. I guess I was hung up on the
> reference waypoint changing after I created the intersection. The
> handbook says that doesn't matter, which of course it doesn't. ;-)
>
> The 530 and the 530W created a slightly different position for the
> intersection of V-264 and V-137.
>
> And, the official FAA position is slightly different than those two. The
> difference is reasonable for an en route airway intersection. I
> wouldn't want to be designing IAPs using this method, though. ;-)
>
> Intersection of V-264 and V137:
>
> FAA:
>
> 34 05 49.9
> 116 54 33.8
>
>
> 530:
>
> 34 06 02.0
> 116 54 50.7
>
>
> 530W:
>
> 34 06 01.9
> 116 54 50.2
>
> It would be interesting to construct this waypoint at a location with a
> different mag var than the location I used and see if that would affect
> the device's calculation. Next time.
>
>
>

Marco Leon wrote:
> "Sam Spade" > wrote in message
> ...
>
>>Marco Leon wrote:
>>I missed that note. But, that note is somewhat different in the 530
>>manual because not reference is made to creating a position using the
>>intersection of two radials.
>>
>>So apparently this radial/radial option was a new feature in the WAAS
>>series.
>
>
> The functionality is in the 530 (A) but it's not explicitly stated in the
> old manual. There is a note in that section but the statement about using
> two radials to create a user waypoint is not there.
>
> Marco
>
>
Thanks for your help.

Indeed it does work in the 530 trainer. I guess I was hung up on the
reference waypoint changing after I created the intersection. The
handbook says that doesn't matter, which of course it doesn't. ;-)

The 530 and the 530W created a slightly different position for the
intersection of V-264 and V-137.

And, the official FAA position is slightly different than those two.
The difference is reasonable for an en route airway intersection. I
wouldn't want to be designing IAPs using this method, though. ;-)

Intersection of V-264 and V137:

FAA:

34 05 49.9
116 54 33.8


530:

34 06 02.0
116 54 50.7


530W:

34 06 01.9
116 54 50.2

It would be interesting to construct this waypoint at a location with a
different mag var than the location I used and see if that would affect
the device's calculation. Next time.

"Sam Spade" > wrote in message
...
> Thanks for your help.
>
> Indeed it does work in the 530 trainer. I guess I was hung up on the
> reference waypoint changing after I created the intersection. The
> handbook says that doesn't matter, which of course it doesn't. ;-)

Out of curiousity, I opened my 430W manual last night and it turns out that
the note about using two radials to generate a user waypoint is NOT in my
version. It states, "The second reference waypoint field (REF WPT) is a
temporary reference only-not a reference that will be stored with the user
waypoint. By default, this field will display a radial from the nearest VOR.
However, you can select any waypoint-by identifier-to use as a reference in
this field."

So it seems Garmin is not consistent in documenting this function despite it
identical operation in both units. I see why it threw you for a bit of a
loop. Using the above note I would expect the secondary reference waypoint
to change with no further functionality possible.

> The 530 and the 530W created a slightly different position for the
> intersection of V-264 and V-137.
>
> And, the official FAA position is slightly different than those two.
> The difference is reasonable for an en route airway intersection. I
> wouldn't want to be designing IAPs using this method, though. ;-)

That's interesting. I wonder what the error works out to be. The difference
between the 530 and 530W is even more intriguing. I wonder if the difference
is a function of the software logic, the database version or both.


Marco

I've wondered how closely the radial projected by a GPS matches the radial
indicated by a perfectly accurate VOR receiver. Does a sophisticated GPS
have a database that compensates for VOR misalignment due to movement of the
magnetic north pole over time?

On Jul 22, 1:23*pm, "Jon Woellhaf" > wrote:
> I've wondered how closely the radial projected by a GPS matches the radial
> indicated by a perfectly accurate VOR receiver. Does a sophisticated GPS
> have a database that compensates for VOR misalignment due to movement of the
> magnetic north pole over time?

Well. there is a great answer to this conundrum!

If you are in regular "desired track" mode, the GPS box applies a
computed,
local declination value to locate magnetic north.

If you go to OBS mode, the GPS box applies the actual
magnetic correction for that particular VOR.

Most of the VORS need to be twisted to real magnetic north
these days, so there will be a difference.

So if you are using OBS mode to overlay a victor airway you will be
fine,
as the V airways are predicated on lining up real magnetic bearings
from VORs.

Smart things, these boxes.
I'm sure all this is due to global warming.

Bill Hale BPPP instructor

Your answer was right but you missed the question.

--
Regards, BobF.
"Bill" > wrote in message
...
On Jul 22, 1:23 pm, "Jon Woellhaf" > wrote:
> I've wondered how closely the radial projected by a GPS matches the radial
> indicated by a perfectly accurate VOR receiver. Does a sophisticated GPS
> have a database that compensates for VOR misalignment due to movement of
> the
> magnetic north pole over time?

Well. there is a great answer to this conundrum!

If you are in regular "desired track" mode, the GPS box applies a
computed,
local declination value to locate magnetic north.

If you go to OBS mode, the GPS box applies the actual
magnetic correction for that particular VOR.

Most of the VORS need to be twisted to real magnetic north
these days, so there will be a difference.

So if you are using OBS mode to overlay a victor airway you will be
fine,
as the V airways are predicated on lining up real magnetic bearings
from VORs.

Smart things, these boxes.
I'm sure all this is due to global warming.

Bill Hale BPPP instructor