The optimal distance between the hub and monitor is about 30-40 feet from the pool. In some cases, we've seen the Sutro work up to 50 feet, but at that range, there is the possibility for missing readings and device disconnections.
The thickness, material, and number of walls between the hub and the monitor can also affect connectivity. The best practice is to place the hub as close to the pool as possible but still remain in the home.
Any covered structure will work as well if your house is too far from the pool, such as a shed, pool house, or garage area. As long as it's shielded from the elements, the Sutro Hub can be setup in any of those areas.