Final Closure on Problem
All need to know what I discovered regarding my DC WiFi Shutdown. Yes, it was a signal strength problem occurring at my home. I fixed it by installing a TP-Link N300 2.4 GHz WiFi repeater.
As to DC not switching back to the AP HotSpot Mode - - @Abhishek filled me in on a DC detail I must have missed so thought it might be useful to other Forum members:
"Netguard, the component that is responsible for switching back to AP mode on STA-association failure was disabled on the DC some time back.
"On CHIP, the reason netguard exists is that if STA-association fails, there is literally no way to correct it short of reflashing the CHIP (and losing all files in the bargain). The flip side to netguard is, at the most minor of wifi hiccups, it would switch to AP mode, and then people who access it remotely would lose access until they could physically approach it again.
"On DC, there are ways to get back to AP without having to reflash or lose files:
"Login over USB and do a config wipe. Remove the sdcard from the DC, put it into a PC (if it has an sd reader, else use a usb-sd adapter), and when you can view the sdcard files in file manager (you should see files with extensions like .ksop, .dtb, a file called zImage, etc). Just make an empty file right next to these files called "reformat_conf" (no extension). It doesn't need to have any content either. Now eject the card, put it back into DC, boot, and the default AP should show up. Any downloaded files would not be lost."
From my experience in the field with DC, I would opt for restoring the AP Outernet HotSpot before leaving an active WiFi network so the next time I wanted to join a new network, I would have to go thru the Outernet HotSpot AP mode to load it. You just have to remember to do this, or you'll be in big trouble Ken