6600 4.2.20 FT8 Wattage Spike

W4RXK

6600 running 4.2.20. Antenna directly connected to ANT 1 for TX/RX. RF power: 70 W

In my Diawa meter, and FRStack3, I noticed a spike in wattage out during the FT8 cycle. TX within the normal operating space of FT8, not band edges. Spike = ~+10w change in the output meters.

Output level appeared normal as described and seen on many of Mike-VA3MW videos. Never in the red. I don't recall seeing my level in the red, ever. It does not appear to be over driven.

With RF @ 70W, I get about 64-66 out due to minor SWR (at TX gain 45). The spike would show as ~+10W on FRStack for about a second. Very brief. Watching it carefully, it would move around the 15 second cycle. Never at the same place.

My DAX TX gain was set to 45. Gemini suggested I lower this, and I did, to 40. At 40, the spike no longer exists and the power output is the same. A little under 70w depending on SWR.

Can someone explain what could cause a spike +10 watts, for a second, during FT8 transmission. It occurred with and without the tuner engaged.

Powered off, pulled plug, waited a few minutes .. did not effect the spike.

Is the new DAX more sensitive to ? than the old one?

W4RXK

Anyone?