Separate antennas for separate bands

Paul,

The flex 6500 has only 1 Spectral capture unit.  Therefore the only way to listen on both would be to have one connected to an RX antenna port, and in that case you would not be able to transmit on it, but you could listen, even in full duplex with that configuration.  In order to have TX/RX capability with a flex radio on multiple antenna ports, you would need one with 2 spectral capture units, like the 6600 or 6700.

The most common configuration would be a tri-band or multi band antenna, or a log periodic, anything that can do multiple bands(but is not frequency agile like a SteppIR). So let’s say you have a 3 band yagi, you can listen to all 3 bands at the same time

Paul, I am not sure about totally useless, but in that configuration you would have to do some switching magic to say listen on 80 or 160 while you were on your ultrabeam.  for instance you could switch the 80 vert to RXA while operating on the upper bands through 40, and reverse them when you want to operate 80.  But I do understand your concern.. and the best flex radio for that configuration are the following models: 6600, 6600-M, 6700.  all 3 have dual TX/RX antenna capability and 2 SCU's.  Single SCU units that behave as yours does are the 6300,6500,6400, and 6400-M.  

Ah that makes senses.  Nice to be able to upgrade antennas!

Not mentioned are diplex or triplex filters that will permit multiple bands presenting to a single connector.
I have also placed a 100w 2M + 6M diplexer at the rig (Antenna1 + 2M amp) with another up the coax to separate antennas and also, at the club station, a triplexer feeding a trap triband beam.   As noted by Chris, this will not work on a SteppIR or similar antenna except as a single band at a time

Paul, your TRX has only 1 PTT output. That answer your question. So you need a Y-cable for PTT and then 2 ways: 1. you always switch one of your PA in standby or 2. you add a switch in this Y-cable and select manually then what PA you will using.

73 Chris