Tyco Electronics MM102014V1 - Manual (Page 56)

MM102014V1, Rev. G
5.25 RECEIVE SIGNAL STRENGTH INDICATION (RSSI)
The engineering display’s RSSI number represents, in absolute value, the dBm level of the signal
received from the OpenSky’s base station transmitter. It represents a negative unit of measure, but a
negative/minus sign does not precede the number in the display. Because the displayed number represents
a negative value, higher/increasing numbers represent lower/decreasing received signal strengths.
Values lower than -110 (125 for example) indicate a possible antenna problem, or radio operation in a
fringe or no-coverage area.
Higher RSSI values, -85 for example (displayed 85), with CBSER values greater than zero (0) generally
indicate RF interference is being induced into the receiver or radio’s antenna system along with the
received signal.
It is not uncommon for an OpenSky signal with low RSSI and degraded CBSER to be decoded by the
radio and heard at the speaker without any problem.
5.26 CONTROL BLOCK SYMBOL ERROR RATE (CBSER)
The engineering display’s CBSER value indicates data distortion or interference. Zero (0) represents no
errors. When operating in RF fringe areas, this number may increase as interference in the received data
signals increases.
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