Nick Gregory G0HIK
Well, initially I'm going to use the 12v amplifier I have already.
Yes, if possible as much 12v kit as possible, I will need a small inverter for the Az/El but a small 100 watt unit should suffice.
I've found the the IC-9700 is very tolerant to supply voltage and runs from batteries nicely. Looking at the circuit I see it has three DC/DC converters in there, but not on the PA supply, so I would imagine the quality of signal would start to deteriorate at 10.5v :), even though it's still giving full power out.
I had considered using a Bias Tee as I was going to used LDF4-50, now it's going to be Superflex, both have thick inners. I had not thought about using the screen on it's own though and I had not considered a P.D. imposed on the braid. Thanks for that info.