GRT and Dynon D10A magnetometer in same wing tip
When I purchased my RV7A from the original builder both magnetometers were mounted on the shelf just forward of the vertical stabilizer. As a result, every time I keyed the radio, magnetic interference was so great that both my GRT EFIS and my backup D10A headings would drift. The drift was so bad that I literally had no idea which was the most correct (neither were very close to actual magnetic heading). ForeFlight got me from Denver (where I bought the plane) to my home in OKC.
After talking to GRT and Aerotronics (who built my panel) I decided to move both magnetometers to a wing tip position. Originally I was going to put them in separate wing tips but D10A wire length limits forced me to place them in the same wing tip. I did my best to ensure appropriate separation from strobe and other electrical interference and paid very close attention to their alignment to within 2 degrees of level to the AHAR units.
I can report that heading differences between the dual GRT Horizon WS and my Dynon D10A have, since this move, (about a year and a half ago) at all times remained within one to two degrees of each other and actual magnetic heading. Strobes, landing light wires, and relatively close proximity of the two magnetometers (about a foot apart) to each other do not appear to impact headings. There is more than 18" distance from the landing and strobe lights from the magnetometers.
I also want to thank Pat Hatch publicly for his patience and support when I installed my Tosten multi-function grips last fall. Without his assistance that effort would have been a disaster. His "Ultimate Hub" is a truly great trim controller.
Jim Harris, RV7A, 2nd owner, N523RM
IO-360, Hartzel CS prop, Older Aerotronics built panel Dual GRT Horizon WS, Garmin 340, 335, Dual 430s, Stratux hard wired to WS, Dynon D10A (backup EFIS)
Retired - Living the dream - And going broke!