Ok, if you were not in a thunderstorm area, then the easiest method would be to just use
the two antenna outputs on the TS-480 itself.
You have a few options, but probably the cheapest and easiest would be for you to buy a
coax relay that switches between two antennas and to ground when no power is connected.
Then you can control this relay either using an I/O port of the RemoteRig RRC, or via
an AC power plug using an IP power strip (which is a useful device in any remote station).
If you get a relay that can handle high power, then you can add an amplifier later without
a change.
I have used other methods as well, e.g. external switches, using amplifier switching (SPE, Acom), etc.,
but these are probably overkill and too expensive if the Microbit solution is too high-end for you.
The Microbit solution is actually quite ok price wise and well integrated into the RRC, but a relay
will do the job for you if price and overkill is an issue.
73,
Mitch DJ0QN / K7DX