solarwind wrote:
> Now I'm trying to sort out the connection between amplitude of the
> radio wave and the power of the transmitter.
>
> So can it be said that by varying the voltage of the antenna, we are
> varying the amplitude of the wave as well as fluctuating the output
> power proportional to the varied voltage? Is it the amplitude that
> governs the output power of the antenna or is it the number of photons
> created? What is the relationship between the amplitude, power, and
> number of photons?

The power out the antenna is proportional to the square of the voltage in,
and forget about photons.

Let's say the antenna is a ordinary dipole tuned to the carrier frequency.
That means it has a characteristic impedence of 75 ohms at the carrier
frequency.  If the transmitter feeds 10V carrier into the antenna, then the
radiated power (ignoring the little loss in the antenna) is (10V)**2 /
75ohms = 1.3 Watts.  If the voltage were doubled to 20V, then the radiated
power would quadruple, and so would the power the transmitter has to put out
to maintain that voltage.


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