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Old 6th Dec 2017, 2:15 am   #4
Join Date: Sep 2010
Location: Cheltenham, Gloucestershire, UK.
Posts: 1,495
Default Re: 'Kalmus' wideband RFPA: info.?

If it does have ALC it will probably be obvious from the front panel. I'd expect the ALC to have an adjustable threshold to allow the user to set the output level over a fairly wide range. This would allow the amplifier to be used for something like formal immunity testing where the amp is driven with a slow swept cw signal and it will level the power to the user requirement. This would correct for the gain flatness of the amplifier and also for any variation in drive level from whatever is being used to provide the swept signal. So the ALC could flatten the output level to within a dB or maybe better.

But usually this type of amplifier will have been designed to have flat gain anyway (for the reasons I gave earlier). So it could be that yours is faulty if the gain variation is worse than about +/- 2dB. But I'm more used to the classic (old!) AR range of amplifiers and the typical specs they offer for gain flatness.
Regards, Jeremy G0HZU
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