Iam going to be installing my RB1 unit and was going to buy a antenna off of Ebay for like $12. I noticed the factory one has a metal back plate is this for any reason or are the cheep ones just as good as the OEM's? Anyone who has installed one let me know what you used for a antenna and what kind and where you placed it.

Thanks!

 

The factory location is under the dash.

 

I know where it goes Im just wondering if I need a antenna with the metal plate on back or can I just get one with out and stick it on the duct under the dash? Someone told me you need a backing plate for a ground for a better signal, not sure if this is true?