7
Input drive and power output:
The amplifier should give full output with approximately 5W input on the HF bands and 8W on
6m band. Excessive input power should be avoided and the amplifier should always be oper-
ated in a responsible manner. If excessive input power is used the amplifier will signal an er-
ror
]
and disable itself for a short period of time before resetting. See error table page 9.
Maximum output power considerations:
All amplifiers have a maximum output and this occurs shortly after gain compression where by
Pin no longer produces a proportionate increase in power output . The amplifier should always
be operated at a point below its saturated output. Trying to extract every last watt by overdriv-
ing the amplifier will not actually help your signal to be stronger, you will in fact cause higher
levels of distortion which will make your signal less intelligible at the distant receiver station.
Running the amplifier a little under max output will also allow the amplifier to run cooler and
make it more reliable for many years of use.
As an example consider the following situation.
1 ‘S’ point on a receiver is usually approximately calibrated at 6dB so for example the differ-
ence between S5 and S7 2 ‘S’ points is 12dB.
The difference between 5W and 100W is 13dB a healthy increase to your signal strength, a little
over 2 ‘S’ points, with the same antenna. Now lets say for example you run the amplifier at a
moderate 90W output by slightly reducing the input power, the difference between 100W and
90W is less than 0.5dB which when you compare this to 6 dB per S point is actually very little
and as the amplifier is not running at its absolute maximum will give a cleaner output with less
distortion that will actually make a difference at the distant receiver for the better!!
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