My cable service appointment this morning was schedule for some time between 8:00 am and 11:00 am. Naturally this guaranteed the technician’s arrival to be 11:02 am.
He was able to quickly determine that the signal strength at the jack my modem was plugged into was low. Or high. Or off. Not right in any event. Moving to the outside of the building he found the gang splitter where the incoming line from the cable company was split into eight separate lines, one each, presumably, for eight apartments. Inside my garage stall he located the splitters for my outlets. It seems that the single source line to Chez Mark was further split, not once but twice. A three-way, with one of the resulting lines split again by a four-way splitter. The apartment has four dual outlets for a total of eight jacks, only half of which are hot.
Having the line split so many times degrades the single so he set it a new line for me that comes straight from the main splitter outside to my modem jack - eliminating the two intermediate splits. The new measured signal strength was much better. Higher. Or lower. Whatever.
Only time will tell if this has solved the intermittent gremlin my connection has been having recently, but I think he has solved it.