[TenTec] Velocity factor

[JACrux]

I thought about 75 ohm twin. I also thought about making my own open wire 
line. But instead I use the heaviest grade of ladderline, 14g (US) stranded 
copper plated steel. Sadly not sold in UK (as far as I know) but light enough 
to carry home from Dayton. Apart from being incredibly strong and flexible, 
the characteristic impedance is apparently a bit less than other grades, 
somewhere between 350 and 400 ohms. 
I run the TenTec auto ATU into about 15 feet of RG-8 coax to a balun hung 
outside the shack, then around 80 feet of ladderline to the top of the pole. 
The only downside is the change in SWR with rain/snow/humidity. But re-tuning 
is a small price to pay for multi-band convenience without switches.