I like the Colibri. Lot's more memory. Used in a "circular" type scheme. The
oldest data is over written. So you don't lose the current flight when you
fill up the memory, you lose the oldest flight. I set mine to a 2 second rate.
At that rate I can fly a long time before I lose a flight. Somewhere around
10.5 hours. There are a lot of other things that I don't like - but the memory
usage is one of the main reasons that I chose it over the competitors.
Dennis Brown


In article , (Mark James Boyd)
wrote:
Set the sample rate to one very 10 to 12 seconds or so. Even 20 isn't
unreasonable and this problem goes away. The sample rate automatically
increases in the OZ anyway. There is no really good reason to sample
more than 5 or 6 times a minute except in the OZ. Reduces download
time and file size too.

Since I don't ever use any waypoints in the VL (because it will
then self-declare if there is a power interruption, can be
awkward to explain) my sample rate
is always the same. I use 9 seconds, because I recall
in the FAI docs (section 3c 7.1b) about a 10 second
sample rate for records/badges. This is the most frequent
rate I've seen in any doc, so I use it and it's frequent enough to
show an unambiguous 360 off tow and good OZ penetration,
yet long enough to ensure recording all day long without the
annoying lowmem beeping.

The FAI docs mention that a power interruption can be
overlooked if a good interpolation of the course is done (3c 13.8),
but these same documents also mention the latest declaration made before
takeoff is the valid one (section 3 4.4.2 a). It's
a little hard to explain if you have two traces with different
declarations because of an in flight power interruption...

So I use 9 seconds, enter no course and no waypoints,
and make sure the memory is cleared each day. Then I do all
written declarations (this is great too since I always have
a valid declaration for every flight, even if it's a year old,
and I don't have to fool with the VL). I then use a moving map Pilot III
GPS for course and waypoints, and reference the VL only for
altitudes recorded. So far I've had no discrepancies greater
than 50 feet between the VL and Pilot III GPS. I was
once grateful I checked the VL altitude, as the pressure alt
recorded was too low for the badge I wanted, and I spent
another 30 minutes climbing an extra 400 feet to the tippy top
of the thermal to make sure I was high enough for the VL.

I can't recommend ever using the VL for anything other than vertical
navigation. There are too many other products out there which
do a better job for horizontal navigation and are much more user
friendly.

Mark Boyd