Tom Ring wrote:
If one has a sealed balun, such as you would pick up at your FLARPS or a
fles market, and the label has disappeared from environmental exposure,
is it possible to easily determine -

1) - if you are sure it's a 1:1 whether it's voltage or current type

Measure between the input terminals with an ohmmeter. A voltage balun
will show a DC short, a current balun an open.

2) - given it's totally unknown, anything about it.

Connect the input terminals together and the output terminals together.
Connect it to your antenna analyzer as a plain series load -- that is,
connect the balun input terminals to the analyzer center conductor and
the balun output terminals to the analyzer connector shell (or reverse
the two -- it doesn't matter). Measure the impedance at frequencies of
interest. You generally need a minimum of around 500 - 1000 ohms for an
effective balun. The angle of the impedance doesn't matter unless you're
running a lot of power, in which case a low angle (that is, a primarily
resistive impedance) might result in objectionable balun heating.

You can also connect resistors of various values across the balun output
and measure the input Z with your analyzer. With a 50 ohm load, you
should see close to 50 ohms in over a wide frequency range. As the load
gets farther from 50 ohms, you'll see more variation between the input
and output Z and it'll change more rapidly with frequency. This can be
corrected if necessary with a matching arrangement.

Instruments available would be a standard multimeter and an MFJ 259 or
something equivalent.

I think I know the answer to 1), but 2) has me stumped. Yes, dummy
loads are a start, but is there an efficient way to get all unknowns
absolutely resolved.

Roy Lewallen, W7EL