Just got my Nuvi 650

Don't use the external if you don't have too. As long as you are getting a good signal, I don't see a reason to use the external one.

However, no, placing it in the back won't hurt anything any more if it was in the front of the car. Just as long as you have a clear sight to the sky.

I guess i should mention why i was using the external antenna. My accord has a compartment below the stereo/ac controls with a sliding door on it. I wanted to house the unit inside there...and be able to close the door instead of having to unclip the nuvi from the windshield each time.

Well, the gps seems to be doing pretty well. I have noticed it takes a minute to acquire the satellites when i start up. Once it finally gets a signal it slowly goes from 200+ feet accuracy to about 16 feet. Is that normal? or does that have something to do with the external? Should i have WAAS turned on in the settings? It's wasn't enabled from the factory.

The SIRF-II chip in the Nuvi does not need WAAS enabled. I have been told it will draw more power from the battery when activated.

But, it will increase accuracy with WAAS enabled. Otherwise, there is no need to advertise/include the WAAS feature.

try it without the external. i have an accord with the same compartment below the radio and it works fine with the std antenna, i have a nuvi 660 .

Thanks, i’ll try disconnecting it and check the accuracy. One other thing i found was that the factory tape for the dash-disk won't hold the nuvi's weight when it's hanging down from it. But the 3m command adhesive works quite well. Plus i like the idea of being able to easily remove it when i sell the car.

I am expecting my 650 from Amazon this Wed. Did your 650 have the latest maps pre installed?