On 08/02/2013 22:35, rk wrote:

So far the best electrical variometer has been good old Zander SR940 (yes better than ZS1), which I've used in 3 different gliders for over 500 hrs. Every other system is a league below SR, including all the new LX varios (both facctories), which is worrying since I believe they have majority of new computer market these days.

What makes the SR 940 the best?

SR is only variometer that can show what is happening when you blaze trough thermal at 200kph. Others are usually all around place.

My answer to this question is Zander SR800. I have about 800 hours in
two gliders with that vario.

My motivation is the same as yours. When the pointer read 2.5m/s flying
through a thermal, you could stop, centre and expect to achieve 2.5m/s
on the averager.

(Zander's meters were bigger than than those used by other instrument
makers. When I had 2.5m/s on the averager, the Cambridge pilots reported
3m/s, climbing at the same speed in the same thermal).

I am not sure if this had anything to do with the electronics but more
to do with the plumbing. The SR800 uses a capacity flask not direct
pressure readings. I think all of the modern devices use direct pressure
measurement and need fancy digital filtering to get the same needle
movement as a capacity system.

My last SR800 has long since died. I now have a B500 and XCSoar etc. The
B500 is a touch disappointing compared to the SR800, but once again I
think the plumbing is to blame as it is a pressure device sharing the
compensation probe with a Winter mechanical (flask) device.

Now I listen to the B500, I look at the winter mechanical if I want to
see a needle and I use the bug trail on XCSoar for thermal centering
intelligence and wind speed/direction into.

But I think I get the best thermalling performance by looking out of the
window and flying the glider. The airframe communicates as well at the
electronics and audio provides reassurance. It is the most fun too!

Ian