With Dynavin you have 2 options:

1- use google maps with tethering to your phone, it works but sometimes it is slow and not really reliable. For this you dont need navigation antenna.
2- best option, install offline navigation software like igo,sygic( the best) and use it as regular navigation, like oem navigation. Fot this you need to install a navigation antenna.
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Philly, Does the unit comes with the Sygic pre-loaded or where can we get the app ?
Plus also does the unit comes with the gps antenna ?
Thanks for your help.