On Nov 9, 1:23 pm, Tom Horne wrote:
Is it possible to ask questions here without triggering an arcane debate
about competing views of theory. I'm about to find out. I asked
earlier in another thread what measuring instruments I would need to
have the use of in order to compare the effective radiated power of
different antennas. As near as I can tell there was no answer.

I built a collinear J pole using copper tubing. I'd like to know if it
is more or less effective at radiating whatever works to the stations
I'd like to be able to talk to under conditions of emergency operation
then say a collinear ground plane or any other omni directional antenna.

I would like to deploy the most effective practical antennas that field
testing can devise and not have to wait until the next breakthrough in
physics to be able to get my local governments Email out to my county's
government, the state government and the responding relief forces.

My question, again, is what measuring instruments can be effectively
applied to the comparison to provide results that will be born out by
real world performance. I have to admit that I find the endless
theoretical debate wearying. As long as it continuous then the
newsgroup will be useless to newer licensees, like my self, who would
like to get some "patient council to the beginner" from those of you who
have been there and done that. Before I have to go there and do that
would be soon enough.
--
Tom Horne, W3TDH

Tom,
I feel that the best results are achieved when measuring the field
strength/receiving effectiveness at a distance far enough away to
avoid near-field effects.
I have used a spectrum analyzer connected directly to the antenna to
make the measurements. Most units can read out directly in dB.
First, I had a friend that was about 2 miles away transmit and I
measured the amplitude of his signal at my home using my different
antennas. I was comparing a 1/4 wave ground plane to a homebrew 5
element beam.
We then reversed the setup, where he took the analyzer to his house
and measured the amplitudes of me transmitting using the different
antennas (same power output, of course)
Antenna gain difference and front/back ratio if it is a beam, are
easily measured. In my case, measurements were very close to
theoretical.
This is an expensive piece of test equipment, but someone in the area
may have access to one.

On the other hand, if you are only looking for seat-of-pants
measurements, find a few hams in the area with analog s-meters and
have them give you relative signal strength readings for your
different antennas. No cost, and the real test is whether you can
communicate effectively. We often send out a rover in a car and do
signal strength comparisons throughout the valley so we know where our
signal needs improvement.
Good luck.
Gary WA7MLK