Have a few questions about the unit. I will be running the unit with transducer mounted on TM 1. Can I run this off my TM battery and still use my TM if needed. 2. It says the antenna is external does this mean I have to buy a gps antenna or does one come with it. 3. Does the unit have down imaging on it or do you have download upgrades to get this option with the side imaging. 4. Is their a clamp that you can buy for it to mount to your TM or do you have to buy a transducer seperate for the TM Thanks for any input.

