On 22 Apr, 18:18, "Jimmie D" wrote:
"art" wrote in message

oups.com...





On 5 Mar, 10:04, Roy Lewallen wrote:
There's no direct way to measure the total power being radiated other
than sampling the field at many points in all directions and
integrating. "Reflected" power is not power that isn't transmitted. You
can find the power being applied to the antenna by subtracting the
"reverse" or "reflected" power from the "forward" power, but that tells
you nothing about what fraction is radiated and what fraction lost as
heat.

Roy Lewallen, W7EL

I believe this to be untrue.
If an array is in equilibrium you have skin depth that give you a
resistance figure as well as d.c. resistance . You also know power
input thus all input and output power is therefore known. Pray tell
what energy cannot be accounted for?
Remember radiation does not begin to occur until the arbitary border
is punctured thus at that time it can be considered as output.
Movement of flux cannot begin until the clock starts
or time begins So now you have a beginning. An enclosed arbitary
border that containes energy and a end section that represents
radiation. You could also use the potential momentum theorem to
determine the exit proportions of electric and magnetic particles to
generate a electromagnetic field as well determining what particles
return to the radiator to serve in the formation of skin depth or
radiation resistance which serves to augument time changing current as
well as accounting for decay. All this requires a smattering of
understanding with respect to Einstein law of relativity which most
will probably tend to dismiss as hog wash especially those who view
the subject of static particles as being useless.
The answer Roy gave is only applicable when an array has parasitics
that either deflect or attract energy with respect to polarity( Walter
note the use of the word "polarity" with respect to antennas)
Ofcourse some will drop back to point out Pointings Vector so this
could be interesting.
If you want to disagree start off with a resonant dipole to ensure
applicability of ones auguments.

Art Unwin

Art
Roy said "There's no direct way to measure" , what you are describing isnt a
direct way.

Jimmie- Hide quoted text -

- Show quoted text -

I stand corrected. You cannot wet your finger and stick it up into the
air expecting that one could obtain a direct measure of radiation.
Most observant of you Jimmie
Art