OK, this is the raw value of rssi, small is good, big is bad.  The signal fails after a value of 85 or so.

The numbers are hex values that convert to -dBm, but I need to fully understand this before I do a proper conversion and/or interpretation.

For reference, on 6.21.12, the transmitter and receiver XBee’s are about 4 feet apart through a double-paned window and metal/concrete surround. The signal strength is reading about 68.

The lowest rssi value I’ve seen on my desk was about 32.