Win wrote:
> I hate to come back to this subject, but I am not sure I understand the
> problem. Is the overshoot a product of the ALC outputted from the exciter
> to the amp, or is it caused within the transceiver at significantly reduced
> power settings.
It's caused by the ALC loop in the transceiver, not the ALC connection
to the amp. When you reduce power with a power level control, what you
are doing is setting the point at which the internal ALC will start
reducing power. When you start talking or press a key, the ALC in some
transceivers takes a certain amount of time to respond, and as a result
you transmit above this power level until the ALC brings it down. This
is the spike.
The TS850s has a power level (ALC) control, but it also has a carrier
(or drive) control. If you set the power control for, say, 20 watts
output and then turn the carrier control down so that there's no ALC
action shown on the meter, there can't be an overshoot because the ALC
is not being used at all.
Actually, the 850 has pretty good ALC and probably doesn't overshoot
much even if you don't do this, but the technique can be used with any
rig that has a drive control as well as an ALC-type power control.
> In either case I should be able to see the overshoot if I put a scope across
> the meter in my power meter. Is that correct?
Not necessarily. It depends on the meter circuitry. You can possibly see
it if you use the scope to look at the RF output of the transceiver itself.
--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco
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