Moved the Pi out of it’s cubby (a panel on a cabinet in the garage), and all is well. Nothing in the syslogs to suggest a fault. I’ve concluded my issue is poor wifi at that location. I did test run it for a while there before installing it, but something has changed – either the sensitivity of the receiver has degraded, or perhaps one of my neighbors has added an access point. (I didn’t move anything into the wireless line-of-sight.) I took my laptop out to that location and scanned the wifi, and was surprised both at the low power of my network, and that I could see 6 neighbours networks, all at power levels comparable to my network. I’ll have to rethink my networking approach. A remote or higher-gain antenna, or use powerline networking. I have a couple of other WiFi dongles to try, in case it is degraded transceiver sensitivity.
What I should have done: prior to mounting the OSPi, I should have scanned WiFi and captured the networks and signal levels. Had I done so, I’d have some data to quantify the change, and possible have known I was on the edge of reasonable performance.
Here’s the linux scan command I used:
sudo iwlist wlan0 scan