I have a Garmin Etrex legend with an internal antenna. When I drove cross country in a 88 Chevy pickup, this thing sat on the dash with great signal everywhere.

Now I get home, and put it on the dash of my 2000 F150, and I can hardly lock or keep signal.

Is there some sort of electrical interference, lead glass or something else causing the satelite signals from reaching the unit?

Do I need to spend another 100 dollars for a active repeater antenna? If so which one?

 

I am not sure which model years but I think some F150's have windshields with metal oxide as part of the glas mixture. The metal oxide can result in a poor signal to the GPS unit.

Many in-car GPS devices are using newer SIRF chipsets that have the ability to function with weaker signals. The specifications for the Etrex don't mention it having an SIRF chipset or a connection for adding an external antenna.