RF problem or not, how would you track down this problem?
To start with I would install some cheap equipment that is more likely to fail so that you can INCREASE your failure rate and get some more data. Maybe consumer grade DSL switch/routers or something like that. Also, talk to radio experts (ham radio) about how to measure the field strength. It is entirely possible that there is some kind of accidental waveguide that channels RF into your facility under the right conditions. Grounding could also be a problem if somebody is pumping lots of volts into the ground nearby. By the way, your timetable sounds like a factory source. Something is done on every shift change, and then maintenance does it once more during the night shift. --Michael Dillon