I recently bought a 2005 260 Sundancer. It has a Garmin GPSmap 546s. It worked fine for weeks then it started loosing satellite every now and again but would recover and be back in business. Last week it lost satellite and now rarely works and if it does only for a few seconds before it looses satellites again. The boat has a radar arch. Trying to figure out if one of these antennas is for the gps. Other functions work fine, bottom machine and other things working fine.