Has anyone successfully revived a Gaffrig GPS speedometer with the infamous dead battery in antenna syndrome. I just tried the Hardin marine antenna which woke it up, but does not register speed correctly.

turn left and go in circles 15 times then turn right than do another 15 circles then dast to 10 mph and hold it their for 15 miles,now put it into reverse and drive backwards for 15 miles,now you will have to get the boat up to 25 mph and do 50 figure eights's..ok if if this dont fix it call mike at gaffrig

If you have a gps/charplotter you can hook the speedo up to the NMEA out signal from there.

A new style antenna has no battery, I had the same problem and got a new one from Teague.