Our club has an EW Model D logger. In the process of getting things ready
for flying this year, I got the loggers out, put in fresh batteries, and did
a test run in the car. I got a strange altitude plot from the EW model D.
It was very "notchy'' with the altitude not changing for several samples,
and then jumping. This was true for both the pressure altitude from the
internal sensor and the GPS altitude from the Garmin.

Looking at the altitude graphs on SeeYou and at the actual log file in
Notepad, I could correlate the "flat sections" with multiple sequential B
records where the altitude would not change for either the pressure altitude
or GPS. The pressure altitude only changes in increments of 5 meters. It
is always a multiple of 5 meters. The GPS altitude is always a multiple of
10 meters.

Anyone have any thoughts or suggestions?

John Scott