Unless you're on a mountain top with a clear view of the city 75 miles away, it's unlikely you'll get the 460MHz signal, even the 150MHz would be iffy.
TV antennas don't work unless they're mounted sideways. TV is horizontal polarized, mobile radio is vertical polarized.
#10 or larger aluminium is good for ground, but unless you're willing to spend a lot if money on suppression equipment, don't count on "real" protection from a simple ground line. You also need supressors on the lead line. And, of course, a good copper plated 10' grounding stake driven fully into the ground.
A simple splitter to combine two antenna leads for reception usually doesn't work unless you're real lucky with lead lengths. In fact, in many cases, it can make things worse due to line mismatch and SWR issues. Definitely a no-no for use with a transmitter.
A switch is a better way to go.
Sent from my Verizon Wireless 4GLTE smartphone
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