It sounds like the start of a film title, Zigbee, NUCs and Wifi, but it's not. Simply put, this blog post is a short reminder to those who use the Zigbee protocol and Intel NUCs. The issue relates to the interference of signals which leads to not only a weaker and slower signal but also higher power consumption.
I recently moved my NUC from my server cupboard to my office where it will remain. There were three reasons for this; on occasion, the server needs to be rebuilt or given a new SSD and as a result, I need the server to have a display. I usually route the HDMI connector through a TX cable back up to the office but this takes time to set up. I could use VNC or something like that to do this, but again, it takes time. So to make it simpler I have moved it up to my own office. The second reason is that it gets quite warm in my cupboard so I was hoping moving it away would keep it a bit cooler. The final reason is the simplistic approach of my cupboard now - it only houses the main network of the house (a small 8 port PoE switch that also powers devices near it such as the Ring hub and provides connections to my other networks around the house, this is my only 2.5GbE network at present), my router and my Ring hub.
However, the purpose of this article is not to inform you of my new changes, but rather to inform you of the issues to which I experienced when moving my NUC. I have a NUC7PJYH as my home server - it's low power but isn't the most powerful little machine. It does, however, support Linux really well and it runs on a variant of Ubuntu. My home server has many containers running on it, a web server, a PBX, a HomeBridge instance and a Home Assistant instance. Generally, it does quite a lot so I like to ensure I have regular backups of it (I've set up a cron to do snapshots of this daily). However, it wasn't until recently I noticed that my Zigbee devices were taking a lot of time to respond when I pressed buttons around the house. This only occurred after I moved the server to my office. I quickly started to realise why. Moving it to my office there were far fewer WiFi devices (I don't have a lot of WiFi devices in the house, most things are on the Ethernet) so I assumed it would have been better. But I had put the Zigbee USB stick on the top of my NUC. It struck me why in my server cupboard I had placed the Zigbee antenna in the corner away from the NUC - interference. Interference from what though? I hadn't even realised this, but the NUC actually has built-in Bluetooth and WiFi.
Having these enabled can seriously impact the performance of the Zigbee hub. I seriously recommend switching these off. Did you know that USB 3.x can also interfere too? Yup, the electrical signals cause a small portion of electromagnetic interference that causes issues with Zigbee.