Garmin GPS 18x: Low-cost High-quality GPS Receiver for DigiTrak Autopilot of TruTrak
Garmin GPS 18x receiving unit Four years ago, with friend Mel's help we installed the DigiTrak autopilot made by TruTrak in our Zenith 601HDS, N314LB. The autopilot requires GPS NMEA 0183 input. To save cost, we supplied that input with the already-installed Garmin GPSMAP 195. In the DigiTrak installation manual, TruTrak advises against that choice since the 2-second update cycle of the GPSMAP 195 is not quite fast enough for the autopilot and may result in wandering flight during turns. That problem did indeed occur, as well as occasional meandering in straight-and-level flight. Recently, the GPSMAP 195 battery needed for retention of user options failed. A replacement battery that nominally should last 10 years failed after eight weeks. Ditto for a second replacement battery. Clearly, it was time to eliminate the GPSMAP 195. Indeed, except for the autopilot, the GPSMAP 195 was no longer needed since the combination of Garmin GDL 39 and iPad installed a year ago produces