Tl;dr: I've deployed several MKR 1010 and MKR 1500s in ABS housings on the exterior of a high-rise building where they suffer from intermittent connectivity. When they do connect, the reported signal strength is invariably high, leading me to rule out range issues and instead suspect possible RF interference from other equipment on the building. I'd be grateful for any tips on testing this hypothesis and mitigating the problem.
Application: the boards collect data from sensors on high rise buildings. Most of the time they deep sleep to conserve battery but connect every 20 minutes to check for a wake command. Extensive testing in my lab and on other buildings showed them to be highly reliable.
MKR 1500 deployment: earlier this year I installed ~20 of these devices on one particular high-rise building and very quickly they suffered from intermittent connectivity. Instead of every 20 minutes some of them would connect only every few hours or even days. Some connected nominally; some not at all. When they did connect, scannerNetworks.getSignalStrength() always reported a high value, typically 28-29 (out of 31).
MKR 1010 deployment: recently I replaced the MKR 1500 with MKR 1010 boards, hoping these would fare better. I installed a wifi router at the top of the building and all of the boards are within 5 m of the router. I'm having the same issue: some boards connect reliably and others only intermittently. Again, when they do connect the RSSI is always high (at least -50 dB).
Code: not sharing my code here because I'm quite certain it's not a code issue, but can do if requested.
Possible actions: the only thing I can think of is experimenting with the broadcast settings on the router. It's a 802.11bgn router (specs here) and I can restrict the channel:
Could doing so improve the connectivity?
Thanks in advance for any insights.