Minimum imp to access point distance?

General
1

I brought a new device online a bit earlier today and it ran fine for several minutes one time and about 30 minutes another. The imp started indicating amber-red repeatedly (as I recall). The gist of my question comes from a comment made in one discussion about an imp “overpowering an iPad” and needing some distance between them. I’ve since moved my CradlePoint router from 4" away to about 12" away and the problem seems to have gone away, although only time will tell.

I’m logging RSSI and seeing -30 routinely. The CradlePoint is supposedly a fairly strong WiFi device. I have another device about 50 feet away (including a brick and concrete block wall) and it’s reporting -66.

I’m wondering if there’s a recommended RSSI (or other general guide) to ensure devices are not too close, recognizing the RSSI measurement only pertains to received signal strength.

2

ISTR the wifi spec says above -30dBm is out of spec (from memory, possibly was -20). Ideally stay lower than that.

This problem can work both ways - hard to tell if it’s the router overpowering the imp or vice-versa.

3

I’m seeing routine -19, -20 and -21 RSSIs, so I’m thinking I’d be smart to reduce the radio power on the router, hoping I can still reach the other device. Might be a combination of power setting and location (which actually might be the better alternative). The other device hasn’t missed an update, so I think the overall connection is solid.

(update) BTW, when the imp restarts, I am seeing an Exit Code “imp restarted, reason: wifi outage” in the log

4

You could always “impair” the closer imp’s antenna, eg put something solid/near the imp to attenuate the signal.

Is there a reason you need the router to be this close?

5

There’s a device in a small brick building with the wireless service and there’s another device about 50’ away (outside). It’s a bit of a challenge getting WiFi service to both at the same time at a satisfactory level. I ended up moving the router about 5’ and cutting the output power to 40% which raised the RSSI to ~ -30 for the one in the building while maintaining it at ~ -75 for the distant one. It’s a bit of a balancing act, but both appear to be staying online currently.

It was a bit of a hoot due to the brick building having a steel door. When I was setting the system up and testing, all was good. However, when I went to leave and closed the door, the one in the building would go offline. This happened a few times. I kinda thought it missed me! I then had a bit of an epiphany and checked RSSI with the door open and closed and saw it change by most 10 points. Evidently, the steel door when closed was creating a reflected path that was increasing signal strength to/from the imp.

I may end up “impairing” it somehow with foil in a baggie, perhaps.