Pulse tuning:
Maybe, maybe not. Look at some typical load impedances of an amp.
3000 volts at 1 amp/2 = 1500 ohm plate load. If you tune with a pulse tune
the plate voltage stays near 3k.
Now tune up with carrier. The plate voltage will probably drop. Let's say it
drops to 2600 volts at 800 mA. (if tuning for max output the tube will not
draw as much plate current with lower plate voltage).
So 2600 at 800 mA/2= 1625 plate load.
With carrier you have just tuned the amp at 1625 plate load impedance which
is higher that with the pulse tuning. This presents a LIGHTER load to the
tubes. Now you switch to SSB and talk with the same amount of drive and the
plate current peaks try to go to 1 amp but they will flatten out before they
make it there because the plate load presented to the amp is too high for
the impedance presented by the tubes now at peak power.
It could go the other way too depending on what the carrier plate impedance
is compared to the pulse tune impedance is. For example if the voltage was
2600 at 900 mA/2 = 1444 ohms. This is a lower plate load than 3kv at 1 amp
presents. So in this case the carrier tune up load would be heavier than the
pulse tune up.
73
Gary K4FMX
>
> Does pulse tuning at max PEP out with a higher plate voltage than normal
> really give you more over head, or less.? IOW, you are tuning up at a
> higher plate voltage than normal as it won't have the normal sage
> related to normal use on SSB let alone CW. Or is the difference not
> worth worrying about?
>
> I normally tune into a dummy load while adjusting the antenna tuner with
> the antenna analyzer, then switching to the antenna which was adjusted
> to the same figures as the dummy load.
>
> > Tuning's impedance matching seems primarily to effect efficiency
> and inversely
> > device dissipation.
> >
> Unless running near the amps limits I'd not expect this to represent a
> problem
>
>
> 73
>
> Roger (K8RI)
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