Re: [TowerTalk] Reference plane for FCC power limit

[Chuck Counselman <ccc@space.mit.edu>]

At 3:58 PM -0700 9/3/03, Bill Turner wrote:
> On Wed, 3 Sep 2003 15:12:32 -0400, Chuck Counselman W1HIS wrote:
>  >  The value of Zo does _not_ completely determine the
>  >  ratio of E/I, whether you take E and I in this formula
>  >  to be real or complex.
>
> I think you're using the word "real" where I would use "RMS" and
> "complex" where I would use "reactive"....

No.  I was distinguishing between real numbers representing only the 
magnitudes of the voltage and the current, and complex numbers (known 
as complex amplitudes) representing both the magnitudes and the 
phases.

"RMS" has basically nothing to do with this.

Also, the notion of "reactive" does not apply to a voltage (E) or to 
a current (I) _per_se_.  It does apply to impedance, and also to 
power.


> I was referring to the RMS E and I at the output of
> the transmitter, which is what the FCC will be interested in.

The product of the RMS E multiplied by the RMS I at the output of a 
transmitter is _not_ equal to the output power of the transmitter, 
except in the special case of a purely resistive load.  (The value of 
the resistance in this case is immaterial.)


> I'm sure if you try to slip your hypothetical stuff by them, they will
> slap on a 50 ohm load, retune to whatever your anode E and I meters
> said beforehand, and quickly fill out your citation.  When you go to
> court, I'm sure the judge won't care any more than the FCC did.

There is nothing "hypothetical" about what I have written in this 
thread.  It is 100% basic AC circuit and transmission-line theory 
that may have been hypothetical more than about 150 years ago, but it 
was proven by experiments and observations, was understood and 
accepted by the experts, and it has been embodied in electrical 
engineering textbooks since before you, I, and even our parents were 
born.

-Chuck, W1HIS

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