[Lowfer] "BT" will be on tonight

[Bob Roehrig]

On Sat, 16 Feb 2002, Ashlock,William wrote:

> That looks like a total system Q of about 100? Can't snarf at that! There
> must be something you are adding to change the resonant freq when you
> connect the transmitter. Can't you measure the voltage and current out of
> the tranmitter to determine the power out (assuming they are in phase
> +/-180deg)?

DUH! Guess I am not thinking today. Well at a current of 700ma I have 160V
P-P (56.6VRMS) so that's 80 ohms. Power would then be 35 watts at the
800ma I can get out of it.

The "transmitter" is a 60 watt rated TOA model P906MK2 audio amplifier.
I am using the 4 ohm output into a toroidal autotransformer. It has 33
turns on it. The coax to the antenna is at the 33rd turn and the amp
output is at the 11th turn so that would be a Z-ratio of 1:9. I have
played with the taps to get max out. If the antenna impedance is really 80
ohms I doubt it matters much that the coax impedance is 50 ohms.



                    73        Bob Roehrig        K9EUI
                    Aurora University Telecom/IS dept.
                    630-844-4898   broehrig@aurora.edu