Using a WiFi analyzer is the most appropriate action to identify the source of interference. A WiFi analyzer can scan the wireless spectrum and help you detect unexpected signals that may be causing interference with your network. This tool can provide information on signal strength, channels in use, and identify possible sources of interference such as other wireless networks or electronic devices. It's important to check for interference across different parts of the wireless spectrum, as non-WiFi devices can also cause interference (e.g., cordless phones, microwave ovens). Adjusting the antenna or changing the wireless channel without first identifying the interference source would be premature and might not resolve the issue. Disabling the SSID broadcast will not affect interference, as it relates to network visibility, not signal integrity.