On 8/16/2012 5:59 AM, Joe Subich, W4TV wrote:
> In addition, if Charlie is using external ALC (he does not say) and
> has the K3's power control set too high, he will see the spike due
> to ALC time constants*in the amplifier*.
It should be noted that when high quality rigs like the K3 are used to
drive a power amp, amplifier output power should be set by using just
enough drive power, NOT by setting drive power higher and using ALC to
reduce it. For at least 30 years, Ten Tec has recommended AGAINST using
ALC with their rigs and power amps in this manner. The only good reason
for using ALC between a power amp and a transceiver is to protect the
amp in case of a failure in the antenna system.
In an excellent applications note on the topic, Tom, W8JI, noted that
many rigs produce a spike of their full power output when their drive
level is set well below full power. For those rigs Tom recommends a
passive attenuator between the rig and the amplifier. The K3 is NOT one
of those rigs -- indeed, it is quite well behaved. It's also one of the
cleanest rigs on the air.
73, Jim K9YC
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