GPS antenna to OnStar Antenna?

[TheGoodHummerMan]

I want to mount an external antenna for my Garmin St Pilot 3 and was wondering if it is possible to split off from the OnStar GPS antenna?

Or, if necessary I could use the Garmin external mount antenna? Anyone else used one? Tricks to mounting it?

Thanks!

Ed

[TheGoodHummerMan]

I want to mount an external antenna for my Garmin St Pilot 3 and was wondering if it is possible to split off from the OnStar GPS antenna?

Or, if necessary I could use the Garmin external mount antenna? Anyone else used one? Tricks to mounting it?

Thanks!

Ed