You could use a few high current (30A) relays. Double pole double throw
types. If you nest (aka: boolean triangle) three of them, you could
easily switch four antennae into one common buss.

Something like the NTE 30amp unit (nicely spaced contacts, and lots of
space between poles.)

If you get ones with 12 or 24 volt DC coils, you can control the whole
matrix with common 3 pair 24AWG phone wire. (you could even get away
with 2 pair if you set them up with common ground)


Good luck and don't forget to use a few toroids on the DC feeds to the
coils!


'73
VE3PMK