Big Endian wrote:
How does one check the balance between two parallel feed wires into a
doublet antenna. Neon bulbs or some sort of meter gizmo?

The easiest way is to use a large sampling toroid such
that the balanced line can be fed through the toroid.
A ten-turn sampling coil will indicate any unbalance.
Note that the balanced line needs to be centered with
respect to the toroid and needs to be moved along the
feedline to obtain maximum accuracy. Ideally, the toroid
needs to be located at a standing wave current maximum
point. Since my choke-balun is always located at a current
maximum point, I can easily monitor my feedline balance.

You can also use smaller toroids on each line and then
superpose the two readings. But the two toroids need to
be identical which is no small requirement.
--
73, Cecil http://www.qsl.net/w5dxp