I proceeded before reading this note. The procedure was to zero the phase meter
on an short and then to test the loaded 2m vertical. The result was +10 dbm
forward (before the 20 dbm pad) and -50 dbm reflected. The coupler measures
about -14 dbm. The total was about -60 dbm, with 34 db of that due to the pad
and coupler. The net is -26 db forward - reflected.

(The phase angle and reflected ware very touchy. It was almost impossible to
adjust by changing frequency. It was easier to 'adjust' it by sitting very still
and moving my arm.)

The antenna is a copy from the ARRL handbook. It is a 4 inch segment, a 1 inch
long by 3/4 inch diameter 5 turn coil, and a 4 inch tip. It is mounted over a 2
foot square aluminum plate. This antenna should have an input impedance less
then 20 Ohms.

How can it measure very close to 50 Ohms? Is there something wrong with this
analysis?

Thanks - Dan

Roy Lewallen wrote:
dansawyeror wrote:

Now that the setup is reading consistently I will 'test' a loaded 2m
monopole over a 1 m**2 ground plane.


I suggest that you start with an unloaded monopole or some very simple
antenna with a well known impedance. (You will of course have to know
and allow for the effect of the finite ground plane.)

You also need to take measures to prevent coupling between the antenna
and the outside of the feedline. The ground plane you mention will help,
but there can still be substantial coupling. Some high impedance ferrite
beads at the feedpoint and another set about a quarter wavelength down
should reduce the coupling to a small value.

Roy Lewallen, W7EL