Bird Technologies 429-83H-01 Series-Manual - Manual (Page 31)

TX RX Systems Inc. Manual 7-9439-6 09/03/09 Page 23
Degradation
The difference between the static sensitivity (load-
connected) and the effective sensitivity (antenna-
connected) is the system degradation which can
be caused by noise or interference (such as a user
on an active channel). At 800 MHz it is unusual to
have degradation greater than 2 dB (and even this
is rare). The degradation value should be recorded
for future reference. Degradation levels in excess
of 1 to 2 dB should be investigated, as this will
decrease the range and performance of the sys-
tem.
ROUTINE OPERATION
During normal operation only one of the two tower
top amplifiers (“A” or “B”), along with the MCU
am plifier (“BASE”), are used to amplify the
received RF signals. The LED’s for the two active
amplifiers will illuminate green. The remaining
tower-top amplifier will be in stand-by mode, which
is indicated by its LED being off. The system soft-
ware also provides an indication of which tower top
amplifier is active. From the default display use the
ARROW button to scroll down to the LNA X
ACTIVE menu which will display the currently
active tower top amplifier.
Upon power-up, the system defaults to operation
on the “A” tower top amplifier (the “BASE” amplifier
in the MCU is always on). Operation can be manu-
ally switched to the “B” tower top amplifier by
pressing the “B-SELECT” switch, which is located
below the “B-Status LED” on the MCU front panel.
The “B-Status LED” will begin to flash, then press
the ENTER button to finalize the selection.
If necessary the system can be re-ini-
tialized via software interaction. From
the default display use the ARROW
button to scroll to the INITIALIZE
menu then press the ENTER button.
Amplifier Monitoring
The system continuously monitors the current
being drawn by all three amplifiers and reveals the
status of the amplifiers in three ways: LCD Display,
front panel LED’s and Form-C contacts (“screw ter-
minals”). Table 7 summarizes the status of the
LED’s and Form-C contacts for various amplifier
conditions.
LCD Display
The LCD display provides extensive status infor-
mation through the menu system including the cur-
rent draw of all amplifiers, connection of the test
transmission line, the tower top box temperature,
and installed software version level.
CURRENT DRAW
Typical displayed values for each of the three sys-
tem amplifiers is listed in Table 8. The current
value for any amplifier can be read from the display
by using the ARROW buttons to scroll down from
the default display. The A and B tower top amplifi-
ers current draw are shown on one menu display
and the BASE amplifier current draw on another.
TEST CABLE CONNECTION
The status of the test cable is indicated by a menu
display. Use the ARROW buttons to scroll down
from the default display. The TEST CABLE sub-
menu will show the message Test Cable Con-
nected or Test Cable Not Connected depending on
the status of the test cable connections. The sys-
tem will operate normally if the test cable has a bad
connection although you will not be able to perform
any diagnostics with the test port. In addition, the
base status LED will continuously display an alarm
(red) condition.
TTA TEMPERATURE
The temperature of the tower top box can be read
from the display by using the ARROW buttons to
scroll down from the default display to the TEM-
PERATURE sub-menu. The recommended normal
operating temperature range for the tower top box
is -30 to +60 degrees Celsius.
SOFTWARE VERSION
There are micro-controllers located in both the
tower top box as well as the base unit so there are
two software versions in the system. Both the
BASE and TOWER software version can be read
from the display by using the ARROW buttons to
NOTE
Amplifier Displayed Value
TTA Amp A ~ 600 ma
TTA Amp B ~ 600 ma
Base Amp ~ 850 ma
Table 8: Typical current readings.