Vertical Card Compasses vs GPS Compass Display
On Sep 20, 8:09 pm, Bill Zaleski wrote:
On Fri, 21 Sep 2007 00:01:32 +0100, Martin Gregorie
wrote:
wrote:
Some of the GPS's have a compass display. Is that a viable alternative
to a vertical card compass (still having regular old style compass as
backup) ?
That works for me. I have a Garmin GPS II+ and the bearing page is my
preferred directional display when I'm flying. My compass is tucked away
at the bottom of the panel for emergency use only.
As it sounds like you haven't seen a GPS II+, here's a description. The
bearing page shows a circular disk containing a large arrow that points
at the selected waypoint. Round it is a ring showing the main compass
points. Like a compass card, the ring rotates so heading is always at
the top of the display. For good measure the heading and waypoint
bearing are also shown as three digit numbers.
Some other basic handheld Garmins (12XL, GPS III+, eTrex, GPSMAP 60 and
76) also have this display page.
You may still be able to find the older models (GPS II+, III+, 12XL) on
eBay. Of the current basic handhelds, the GPSMAP series look the best
suited for our use because all controls are on the front next to the
display. The Geko series are too small to be practical while the eTrex
series have their controls on the edges which probably makes a panel
mounted one harder to use.
A GPS can not, and will not display heading. No GPS can do this. The
most it can do is display track, which is also heading only if there
is no wind correction. It can not be substituted for a compass.- Hide quoted text -
- Show quoted text -
I love my vertical card compass. It is a PAI-700. I have it mounted
on the bottom of the pedestal where I occasionally look at it. No
problems with sticking. I use it to verify rough heading before my
GPS has a chance to register my track. In some parts of the country
the landscape is monotonous without distinguishing landmarks such as
mountains or ridges. I also believe that a compass is required
equipment for any aircraft - GPS is not a substitute.
Tom Nau
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