That is why, if it is in the budget, buy the latest generation instruments. I have compass module on LX 90XX, compass on Butterfly, and Bolhi compass, They all work within two degrees of each other. The LX90XX and butterfly always agree.

On Tuesday, September 27, 2016 at 8:21:44 AM UTC-7, krasw wrote:

Even Zander compass was very sensitive to installation. I installed one Zander system to a LS8 for WGC years ago and calibrated it with factory calibration compass. It worked fantastically giving very accurate readings. After that my club bought similar system to D2 and it didn't work at all, even after many calibration attempts. I have flown third glider with similar setup, and that also did not work. We never understood why. With current knowledge of compass sensor installation problems, there might have been speaker or something too close to compass.