Hi  @robcool 

Is it best to have them both on the main site (where the controller and the Internet connection is), or better to have them configured to the remote site, or does it matter?

>>>It doesn't matter. But if there is no special configuration needed, I will recommend putting them into the same site, it's more convenient for management. For example, you don't need to change the configurations under Site settings twice.

What is an acceptable amount of interference? 

>>>

An acceptable amount of wireless interference really depends on your specific network needs. However, when measuring Wi-Fi interference, a signal-to-noise ratio (SNR) of 20 dB or more is generally considered good and should provide reliable network performance.

The SNR is the difference between the received signal and the background noise level. A higher SNR means a better-quality signal.

For example, if your received signal strength (RSSI) is -50 dBm, and your noise level is -90 dBm, your SNR would be 40 dB, which is excellent.

On the other hand, if your RSSI is -70 dBm (a weaker signal), and your noise level is -80 dBm, your SNR would be only 10 dB, which might result in poor performance and connectivity issues.

Please note that these are general guidelines and actual acceptable levels can vary depending on the specific requirements of your network and the devices using it.

The best way to avoid wireless interference for outdoor units is to install them higher to avoid ground obstacles. We have an installation guide for outdoor access points:

Long distance wireless connection concerns when using outdoor access point