Tom,
The EDZ is a non-resonant antenna about 1.25 wl long. The exact impedance
values at the feedpoint will vary a bit depending on exactly how long you
make it, but the pattern will not vary by very much. One of the problems
with giving wire formulas for antennas is that they look like Ohms Law.
But, in fact, they are only general guidance approximations.
If you plan to operate that antennas with 450-Ohm line to an antenna
tuner, then exact length of the EDZ will not make much difference to
anything so long as you are in the ball park. About the only time the
length gets a little critical is when folks devise special matching
systems applied right at the feedpoint to get a coax match or something
else. Since those systems may depend on the more exact resistance and
reactance values for a precise length (which is likely to be good only at
certain heights above ground), more exact pruning may be needed.
For most installations, the resistance will range between 100 and 250
ohms, while the reactance will range between 500 and 800 ohms capacitive.
What your tuner sees will be a function of the line length. If your tuner
cannot handle what it gets, adding a length of line may change the
reactance enough to allow the tuner to effect the match.
Hope this is useful.
-73-
LB, W4RNL
L. B. Cebik, W4RNL /\ /\ * / / / (Off)(423) 974-7215
1434 High Mesa Drive / \/ \/\ ----/\--- (Hm) (423) 938-6335
Knoxville, Tennessee /\ \ \ \ / / || / (FAX)(423) 974-3509
37938-4443 USA / \ \ \ \ || cebik@utk.edu
URL: http://web.utk.edu/~cebik/radio.html
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