View Single Post
  #6   Report Post  
Old June 11th 06, 06:02 PM posted to rec.radio.amateur.antenna
Richard Clark
 
Posts: n/a
Default measurements at the antenna

On Sun, 11 Jun 2006 09:35:31 -0700, dansawyeror
wrote:

The first set of test measurements were taken on a 2-meter loaded vertical.


What frequency?

Two
voltage readings were taken via a high impedance scope probe,


This sounds like a set up to imagining better results than can be
obtained. Scope probes are not magic detectors and what you describe,
following, sounds like wishing:

one at the
feedpoint of the coax center connection, and the other from the connection of
the coax shield to the antenna ground.


A Scope probe has two (2) connections, and at any frequency in HF and
above, their separation is going to have a significant impact on
measurement. You never say just where the second lead goes for each
voltage reading. If you made NO second connection (and just left that
at up to the far end of the probe's connection to a mystery box) then
you have definitely confirmed that dream is in Technicolor and
surround-sound.

In this case the ground is a simple
raised metal 1/4 inch screen mesh about 10 square feet.


This is rather less than fully descriptive as 10 square feet can take
many forms.

The antenna was tuned to resonance. The relative voltage readings were the
center conductor was 2x the ground reading. I do not have a way to measure
current at the base at this time.


And this raises one particularly pointed question:
Ground was at what potential with respect to ground?

However looking ahead, with power = iv would this imply about 2 times the energy
is being radiated from the vertical element as through the base?


Hi Dan,

There is far too much ambiguity in what you post. What is posted is
fraught with conceptual problems. Basically, you've managed to obtain
two voltages whose relationship is meaningless at best. I'm sure the
potentials exist, but they define a circuit that has no practical
application (and that circuit is NOT the antenna NOR its ground
screen).

In short, just what do you think you are achieving (another
ambiguity)?

73's
Richard Clark, KB7QHC