I’ve always wondered why I had wifi issues in my garden office on my phone and more generally everywhere else in my garden. It’s only 10m away from an access point with good quality external aerials. Which should give decent coverage over the entire garden and offices.
I have a central Draytek 2820n router connected to a Netgear GS724t switch (then another in my garden office). There are two Draytek Access points connected to the switch. AP-800 and AP-900. Both legacy products now, but OK.
Wifi reception in the house is generally decent. But in the garden and our garden offices it is rubbish. There are multiple Smart switches that are always disconnecting (in fact I threw one away a few years ago and replaced it with a new one). A pair of Sonos speakers that are always disconnecting (though they should be using SonosNet and not general wifi) and a Raspberry Pi on the boat that I can rarely reliably SSH to.
Our garden has some overhead power cables above it. These are 11kv with three phases and power the entire village.
Yesterday morning I just noticed that I was getting a very decent wifi signal on my phone (20Mbps down). Then it dawned on me that the cables are turned off today for tree work and the village is being powered by a diesel generator for the day. The naive “jumping at straws because this dammed wifi problem is never going away” person in me immediately assumed that interference from the cables was the issue
Then more knowledgeable people than me told me that a 50hz electricity cable will not interfere with a 2.4/5Ghz wifi signal. The frequencies are too different. Still something is awry. I also noticed that the three smart plugs in my garden that are generally problematic are connected without issue. Same goes for two Sonos speakers. I could even connect to the RPi with a decent connection. Enough to update Raspbian without having to use Tmux.
However, then the connection fails again and the power has yet to be restored to the cables. So what is the problem?
The Draytek router has AP central management and I configure the two Draytek access points using that tool. I’ve rarely looked at the config pages of the actual APs.
But now I looked at one. Turns out that it was using two wifi networks with the same SSID.
The AP in the house had both SSIDs connected to LAN-A, but the AP in the garden had one of these “pseudo” networks connected to LAN-B. The LAN-B is not connected to anything!
So when the power went off the APs rebooted. Then the devices get a decent connection. But as the phone roamed it switched to the SSID with no network connection and so the iPhone goes crazy with no internet connection and switches to 4G. I have no idea why the Smart switches disconnected though.
I just turned this off on both APs and everything now connects flawlessly with a strong signal. I have had this problem for years…! Sheesh…!
UPDATE March 18, 2023
So the wifi failed again. I went back to check and the multi SSID option had been re-enabled. Turns out the AP Management tool on the router has a profile that enables it, and it kept cloning it to the access points. Now that’s fixed. Fingers crossed.
UPDATE April 18, 2023
So the problem was not fully solved. The issues above were real, but the heart of the problem was hardware. In these days of reliable hardware how odd to have an issue that is not PSU related. I swapped out the AP, but the only spare AP I had did not have a built in Ethernet switch, and there’s an IP camera attached to the existing AP. So I disabled wifi on the faulty AP point (Draytel AP-900), used that as a switch and plugged in the Ethernet portless AP (Draytek AP-710). For a week before our holiday and the few days we returned it has proved to be faultless. I do need to remove that faulty unit completely. The AP in the house is plugged into an adjacent switch and so only needs a single Ethernet port. I’ll swap the two over soon.