On Mar 24, 12:57*pm, jcarlyle wrote:
Tim, that's very interesting. I have a friend who bought a MRX last
summer. While flying with him last fall I noticed that his MRX was
misreading the altitude of the tow plane. He's planning on sending it
in, but what with his problem and now yours I wonder if there was a QC
problem at Zaon last year. Don't get me wrong, I love my unit and I
know several that are performing exactly as they should - but they're
all older units.

-John
[snip]


By how much? And just compared to the towplane? The altitude of the
towplane sent to the Zaon is digital. So it is unlikely to "misread"
it. It uses it's own internal altimeter to calculate the relative
altitude. I would hope they agree to 100' or so. One issue is the Zaon
pressure sensor is exposed to ambient cockpit pressure and not the
static line pressure, so opening and closing vents/speeding up etc.
might affect the relative altitude it displays. If the difference is
more than a few hundred feet I'd next suspect the pressure sensor in
the Zaon.

It may be worthwhile before sending the Zaon back to compare what the
Zaon says to another aircraft that has a transponder that shows the
encoder's pressure altitude and play with opening and closing vents.
Of course if it is just the tow plane then it's encoder may also be
faulty, or maybe it really is an RF related problem that only happens
when close to the other transponder (but unlikely).

Darryl