Mike

I'll top post this because it might not be appropriate for your situation.
I dont know what you consider "simple equipment" and I dont know what
equipment you already have. I'm a *do it yourselfer* and recently built a
simple slotted line from Home Depot tubing, and picked up a "very
affordable" ($25.00) generator and voltmeter ($20.00)at the TRW HAM swap
meet. This set up allows me to determine the impedance of the baluns and
dipoles I'm interested in at 137 MHz.
Iy may be that the slotted line would be more difficult to build for 432.
And the idea of constructing something like this isnt of interest to you.
But, it sure works well at 137 MHz for evaluating ferrite tubes.

Jerry




"MikeN" wrote in message
...
Back on 25/04/03 re "Choke balun impedance recommmendations" Roy
Llewellan wrote:

"By all means, the slide rule is fine.

To measure the common mode impedance of a choke balun, simply wind a
piece of wire on the core with the same number of turns as you'll use
for the actual balun. Connect one end of the wire to the center
conductor of the antenna analyzer connector and the other to the
connector shell. Read the impedance at the frequency of interest. Or
if you prefer, you can wind it with a short piece of the actual coax
you'll be using. Connect the two coax conductors together on each end
of the winding, and measure as you would with a single wire. If the
impedance is out of the analyzer's range, you can use a different
number of turns and the relationship that the impedance is
proportional to the square of the number of turns.

Use the same method to measure a W2DU type balun (ferrite cores
slipped over a coax line). If the measurement is out of range, measure
a different number of cores and extrapolate -- the impedance is
directly proportional to the number of cores.

Roy Lewallen, W7EL

My queries:-

Would this method give meaningful results if used at 70 cms using the
UHF range on something like a MFJ antenna analyser?

I could pop various beads onto a short piece of coax and determine the
relative effectiveness, but how good would this be for absolute
results?

Thanks