RB wrote:
Some questions about a 140' dipole fed with ladderline from an unbalanced
tuner to work 160-10m:

1. Does it matter if the balun is placed on the tuner output, or at the
dipole center feedpoint?

A balun placed at the dipole center feedpoint has BALanced
ladder-line on one side and the BALanced dipole on the other,
both of which are balanced. So why on earth would anyone attempt
to install a BALanced to UNbalanced device at a point where only
balanced environments exist?

2. Which type of balun (voltage/current) would be best for
centerfeedpoint
use?

What you need is a BALBAL. Good luck on finding one at a decent
price that works with the impedances you will encounter.

4. What ratio balun would be optimal for either application?

A Balun should only be installed at a BALanced to UNbalanced
discontinuity. Forget about trying to install them anywhere
else. Most hams who understand what they are doing use a 1:1
choke-balun at the BALanced to UNbalanced point. Take a look
at my 130 ft. all-HF-band dipole (click below)
--
73, Cecil http://www.qsl.net/w5dxp/notuner.htm