Figure 5-11.—The LMS-11 Net Display in PU History Mode.
SIG PWR. —The total signal strength of the 16
tones, measured in dBm. A value of -51 indicates that
no signal was received.
SNR. —The signal-to-noise ratio, as measured in
dB. The SNR is calculated as the average power in
the data tones divided by the average power in the
noise tones. The LMS-11 can measure a SNR of near
34 dB. A number preface by the greater than symbol
“>” indicates that the average power in the noise tones
was below the measurable threshold. In this case, the
number represents the data tone signal strength only.
An SNR value of 30 or higher is considered excellent.
An SNR value of less than 10 is unusable.
FRAME CNT. —A count of all data frames
received over the specified number of cycles. Data
frames include the phase reference frame and control
code frames in each message. A value that is
followed by a “?” and color-coded yellow is displayed
if the frame count of a picket station average is less
than or equal to six frames. The two start code
frames, the phase reference frame, the crypto frame,
and the two stop code frames would account for the
six frames. Therefore, if a picket unit transmits six or
less frames, no actual message data is being received
and may indicate a problem with the computer or DTS
of the unit. A yellow color-coded value followed by
the “?” is added for an NCS when the number of
frames is equal to or less than eight. The two
additional frames account for the next station address
at the end of an NCS report.
PERCENTAGE THROUGH. —The %THRU
column is a number that indicates the percentage of
message data that is received error-free. the
percentage is found by comparing the number of
error-free message data frames with the total number
of message data frames received.
CF. —This is a percentage of control code failures.
A PU with strong signals that never misses a call will
have a 0 % code failure. A PU that never answers,
such as a dummy PU, will have a 100 % code failure.
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