For those of you that have aftermarket GPS systems that use an external antenna (similar to below), where would be an ideal location to mount it? I am thinking of drilling a hole from the passenger compartment through the firewall and mount it somewhere behind the engine. Would it be able to get signal there, or would the hood interfere?

 

You are going to want it outside the car, mine use to be under my sunroof visor

 

I put mine right on top of my kenwood dnx and the reception is perfect.

 

I have a Kenwood DNX5120 and my antenna is mounted on the dash right in the middle between the defrost vents nudged up against the windshield

 

When choosing where to put mine, I had read that anything metal will block the signal, but plastic and glass are ok. I took out the clock, and wedged the antenna between the top of the actual clock and the housing it sits in. So it's completely hidden and gets a strong signal!

Having said that - I'd imagine the hood and heat from the engine compartment, water splashing up, etc.. would all make for a poor environment to mount the antenna. Save yourself from drilling a hole through the body and keep it inside!

 

THIS! I have both my GPS antenna and my XM radio antenna on top of the clock under the clock housing. Works great. Satellite reception is perfect although it will cut out for 2-3 seconds when going under a bridge or overpass.

 

top of the windsheild behind the tint strip. Near where the rearview mounts.

 

Mines has a magnet on the bottom, so i sat it on the metal where the rear sub is mounted, underneath the speaker grill. I took the sub out though, and I have one in the trunk. So I don't know if you do and if the vibrations would cause issues