On Sat, 3 Jan 2004 21:18:33 +0800, "Richard Hosking"
wrote:

As I understand it the output impedance approximates to Vcc*Vcc/Po, where Po
is output power and Vcc is the supply voltage

I'd be interested to see the derivation of this.

It looks like your measurements point to 50 ohms as about right. How were
you measuring the voltage? - this might affect the measurement

I did the same thing (using different resistor values and then
calculating by V^2/R like the OP has done. It worked for me. The Zout
of my particular design was 140 ohms, though - just right for a folded
dipole. I used 2n3904 transistors; they appear to give a better gain
than 2n2222s.
--

"I expect history will be kind to me, since I intend to write it."
- Winston Churchill