larry wrote in
:

Geoff Schultz wrote in
:

You don't need to do this as software on the C120 will allow you to
monitor the traffic on the NMEA and SeaTalk busses. I think that
you'll find this in the System Integration screen. This is also
where you'll see the error counts.

If it's not fast enough to render the raster....when does it have time
to log data??

Why are you making up this kind of statement when you clearly don't have
any proof of this. I suspect that he's most likely feeding garbage to the
chartplotter and it won't/can't draw the chart, leading to the blanking. I
can easily imagine this happening if the lat/long is changing too rapidly
for the system to redraw. When the lat/long changes slowly enough, that's
when he sees his position jump. You can't expect to feed garbage to a
system and have it behave "correctly" when the lat/long change delta
exceeds anything reasonable.

-- Geoff
www.GeoffSchultz.org