RadioBanter - View Single Post

November 22nd 03, 07:12 PM

(Tom Bruhns) wrote in message om...
For instantaneous values,
Vf2 = (2*Z2*Vf1+(Z1-Z2)*Vr2)/(Z1+Z2)
Vr1 = ((Z2-Z1)*Vf1+2*Z1*Vr2)/(Z1+Z2)

My ISP doesn't seem to be making it lately so I am posting from Google.
Your equation represents Vf1 times the transmission coefficient plus
Vr2 times the reflection coefficient. This is perfectly logical but
IMO doesn't represent what is happening in reality. I hope I am wrong.
Re-arranging the terms:

Vf2 = 2*Z2*Vf1/(Z1+Z2) + Vr2(Z1-Z2)/(Z1+Z2)

For the example presented, I don't think there is enough interference
to support the above superposition. Again, I hope I am wrong but please
bear with me while you prove I am wrong. If I am wrong, it will resolve
something I have been wrestling with for three years.

Please calculate the two voltages, superpose them, and calculate the
resulting Pfwd2 forward power and then let's discuss the results.
--
73, Cecil, W5DXP