You are not hurting the amp or the K3, but you are making the transmitted noise much worse.
Here is an example.
I use an IC-7300 on 630 meters with a transverter that only requires 5 watts of drive. If I back off the Icom to 5 watts, my transmitted noise seriously degrades.
Since on 630m I need more loss on receive anyway, I put a 10-dB 75-watt Bird attenuator between the output of the 7300 and the input of the transverter. Now I can run the 7300 at 50 watts instead of 5 watts. This improved my transmitted noise by 9 dB.
On another subject in respect to the K3, if you are running the K3 at 10 watts, the PA is out of the circuit. On SSB the odd-order transmit IMD (splatter)
at 10 to 12 watts is poor compared if the K3 is run at 35 to 45 watts. If I wanted a cleaner SSB signal from a transmit IMD standpoint, I would run the rig at around 35 watts and whatever the KPA-500 put out. I would also have my K3 power supply set for
14. 5 volts, and have a nice short power cable from the power supply to the rig so the voltage drop in the wire was minimal.
On Behalf Of Fred-K0FG
Sent: Saturday, January 12, 2019 3:23 PM
Subject: [Elecraft-K3] phase noise
After the discussion about phase noise I have a question. When I want to operate at an output power of 100 watts, or a little above, I frequently turn on the KPA500 and turn the power out on the K3 down to 6-10 watts. Was thinking I
was being kind to the amp and to the K3. Am I wrong in doing that? Am I doing more harm than good?