Not Philips Hue BUT ST have crippled my Outdoor sensor - ANSWER, it was out of range!

[JDRoberts]

@Matholwch12

also assumed that it was using the Zigbee network of Hue, or is it using a seperate ST Zigbee network?

The Hue bridge forms one Zigbee network with devices that are connected to it. The SmartThings hub forms an entirely different Zigbee network with devices that are connected to it. Devices on each network repeat only for devices connected to that network. The two coordinators communicate with each other over the local Ethernet LAN, not by Zigbee.

@Matholwch12

Could be that ST runs some periodic check for weaker signals, and culls those connections? As initially it is all connected ok for a few hours (so not a weak signal initially).

Sort of. Each Zigbee device checks in with its own coordinator periodically, usually once an hour. Miss too many of these, and the SmartThings cloud will mark the device “offline” as part of the ST “device health” protocol.

Strong WiFi signals can drown out Zigbee, causing check ins to be missed, so sometimes periodic loss isn’t because of range, it’s because of WiFi traffic nearby.

You might find the FAQ on range helpful. Start with post 11 in that thread (this link will take you directly there). Read that, then go up to the top and read the whole thread.

A Guide to Wireless Range & Repeaters

One more thought. While I understand the marketing reasons for the decision, the fact that SmartThings gives customers zero guidance on how to set up a network backbone does lead to a lot of frustration that shouldn’t have to exist. if people knew that .1) The hub should be located centrally in the home, both vertically and horizontally. Don’t put it in a garage or basement as those have concrete and pipes and metal objects which will reduce signal. If your Internet router is off in some inaccessible corner, you can use a Wi-Fi access point that has a ethernet port on the side and plug into that. Also, the hub should not be put in a cabinet. You just want to make it as easy as possible for signal to spread around your house. .2) you need one device that can repeat about every 40 feet…