I had bought a new antenna, but I was waiting until I got it installed until I replied to my post. Coincidentally, that just happened today (finally!).
The antenna I got was the following:
http://www.gpsgeek.com/products/ampl...h2o-ifinderpro
(The annoying logo on the antenna comes off pretty easily with nail polish remover.)
For other people looking for a G4 replacement GPS antenna, you need a male MCX connector (must be a straight connector; the 90 degree ones won't fit).
John