TMA2Q/LPC2Q Tower Mounted Amplifier Instruction Manual
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V. Maintenance
A. Purpose
This section describes preventative maintenance that is performed to ensure the reliability of the TMA2Q tower
mounted amplifier and LPC2Q LNA power coupler assemblies . The tasks are simple and routine and will keep
the equipment in top condition.
Caution
: Observe anti-static discharge practices at all times.
Caution
: Do not disconnect or reconnect the transmission lines between the TMA2Q while power is applied to
the LPC2Q. Always turn off the LPC2Q and disconnect the power supply from the LPC2Q before disconnecting or
reconnecting the transmission lines.
B. Annual Preventative Maintenance
□
Brush dust off the equipment being careful to not disturb the connections and power switches
□
If additional cleaning of the enclosure and panels is required, use a damp cloth; DO NOT use any
chemicals and do not allow any liquids to enter the enclosures
□
Check for loose connectors and frayed or damaged insulation on cables
□
Check that the power supply voltage at LPC2Q within the range 11...15 Vdc
□
If a wideband noise source is available check the noise performance. A noise source with about 5 dB
excess noise ratio (ENR) is required. When making transmission measurements all unused RF ports
should be terminated with 50 ohm terminations. Note that when the Y-Factor method is used to
measure the noise figure, the coupler combines the cold noise from both amplifiers but only the hot
noise from one amplifier leading to 3 to 4 dB higher measured system noise figure than would be
expected from one amplifier
C. Additional Maintenance Tasks ~ Perform Only As Necessary
1. Remove internal chassis from TMA2Q Assembly
Caution
: Observe anti-static discharge practices at all times.
Tools: 5/16 in or 8 mm open-end wrench, Phillips No. 2 screw-driver, 5/16 in or 8 mm torque wrench
a.
Note that the internal connections are marked red and green with fingernail polish;
b. Carefully remove each LNA power cable connector from its corresponding power supply module;
c.
Remove the SMA-M connectors from each LNA Out port;
d. Hold the LNA module to keep it from turning and then unscrew the SMA-M connector on the LNA In
port. The SMA-M connector is part of the N-M adapter connected to the lightning arrestor;
e. Handle the two LNA modules very carefully and set them aside; do not strain the soldered power cable
connections on the LNA modules;
