peter gerba wrote:
>
> Hi Tom;
>
> If I measure output power as key down (CW) this differs from peak
> envelope power.. yes ?
Hi Pete,
Key down CW power is the same as PEP CW power if the envelope has no
distortion or amplitude modulation, but when you switch from CW to SSB
the output power generally goes up.
The reason for the increase can be from multiple sources. Capacitors in
the system store energy, and bias voltage is often a bit lower while
supply voltages are a bit higher on SSB.
>
> Let me restate this: don't most SSB peaks exceed the CW key down output,
> given the same voltage and current to the finals ? Am I splitting hairs ?
Not if the voltage and the drive power remains the same.
If the voltage on the amplifier increases when you go to SSB and
everything else is the same, the power output generally increases by
about the square of the voltage ratio change. A ten percent voltage
increase (1.10 : 1 ratio) produces about 21 percent power change.
73 Tom
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