Garmin 430 question

"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