Extra shark fin on a 2022 3500HD Silverado

[oakhurst7]

We enjoy camping with our 3500 Silverado and carry a camper in the bed of the truck.  The problem is the over hang of the camper blocks the shark fin thus we have no GPS or XM radio.  I want to add a second fin on the engine hood in order to obtain reception.  Two questions - 1. Does the fin need to be connected to metal for the ground plain effect (if so, was thinking of mounting the fin on the plastic piece on the hood and if the fin required a ground add a ground wire) - 2. where is the location of the black box within the dashboard? 

 

[gemarsh]

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