Long time since last post.
https://www.rabbitears.info/s/371849
Signal quality degraded over the pandemic.
Sutro Tower engineering done for time being.
I maybe now experiencing cellular interference.
T-Mobile LTE service officially available in my area.
T-Mobile tower between me and Sutro antennas.
SiliconDust support confirmed my tuner showed " very big spike of cellular phone activity at about 623MHz".
Big hourly and daily changes in signal quality.
(see tvfool.txt)
So could be something external to my antennas/amp/tuner.
I plan to order LTE filter which will block above 608 MHz.
Place filter after antennas and before RCA mast amp.
Will report back after experiment.