I have a 5th Gen Airport Extreme running firmware version 7.7.7. According to Airport Utility, all of the connected devices have an "Excellent" connection, with a data rate of 300 MB/s, an RSSI in the -55 to -59 range, and 802.11a/n mode. That suggests things are fine. BUT, on a MacBook Air I have installed WiFi Signal, and that software tells me that in most of my house, I have at best a "Good" connection, and in many places a "Poor" connection with a S/N ratio of about 22. Even when the laptop is in a place where WiFi Signal reports a "Poor" connection, Airport Utility tells me that the Airport Extreme is reporting an "Excellent" connection. Whom do I believe here? Are these two data points telling me different things? How do I assess the validity of what I see?