The Garmin GNS430 comes with an antenna. The WAAS antenna is different from the regular 430 unit. At the antenna end the cable needs an TNC connector instead of a BNC, the tray end is a BNC like the 430. The cable must be RG400, RG58 is not acceptable (just had to change mine out for the WAAS upgrade).
Martin Sutter
building and flying RV's since 1988