The FT1000MP automatic aerial switch
the FT1000MP has two antenna inputs which can be selected individually
for each band you still have to manually select the aerial if you have
more than one aerial and a linear amplifier other than the Quadra.
The circuit shown below is for a BCD to decimal converter circuit which reads the band data information from the Band Data connector on the rear of the FT1000MP allowing a separate aerial to be selected for each band if desired. The 8 pin DIN connector appears to be standard on all/most recent Yaesu models including the FT-2000, FTDX5000MP and the interface should work across the range.
The 4028 IC give one of 10 output dependant on the BCD input from the FT000MP. The outputs from each of the 10 'bands' is linked by jumpers to the relay driver transistor for the desired aerial. Only three relay drivers are shown but it is possible to extend this to 10, one per band, if required. You can connect multiple bands to any one relay e.g. 160m, 80m and 40m to aerial 1 (say a trapped Dipole) 20m, 15m and 10m to aerial 2 (say a Yagi) and anything else to aerial 3 or mix and match to suit yourself. The easiest way is to measure which output switches 'on' for the band you want and link to the relay you want.
I used open chassis relays bought at a radio rally rather than proper RF relays. It is proposed to remote mount these relays in a weatherproof box nearer the mast to reduce the number of coax cables coming back to the shack at some point in the future.
The BCD converter/relay driver unit is built into a small Hammond enclosure and sits on top of the rig. Unfortunately I can't find the PCB layout I used to make this, but the layout is not important and Veroboard can be used to construct it.
Yaesu Band Data Connector
(Common to many models)