Comtech EF Data LPOD - Manual (Page 24)

LPOD C-, X-, or Ku-Band Outdoor Amplifier / Block Up Converter (BUC) MN-LPOD
Introduction Revision 10
1–6
1.4.3 Cooling System
The LPOD contains a robust heat sink and thermal design to maintain a low operating
temperature. The PS 1 contains one temperature-controlled fan, and the PS 1.5 and PS 2 contain
two temperature-controlled fans that are monitored by the M&C board. The fans draw cool
outside air in across the power supply and specialized heat sink. The amplifier module
temperature is monitored and, if for any reason the amplifier temperature exceeds a safe preset
limit, the amplifier module supply is shut down to protect the unit from thermal failure.
1.4.4 Monitor and Control (M&C)
The LPOD includes a microprocessor-based system that provides monitoring and control of the
essential parameters of the unit. The user interfaces with the unit through the M&C system via
the remote control/discrete communications port. The unit is capable of either RS-232, RS-485,
or Ethernet remote communication. A discrete mute control and relay status output is also
available.
The M&C system monitors the fan speed (PS 2 only), unit temperature, all power supply
voltages, power transistor currents, output power, etc. Should a critical monitored parameter
fail, the unit will mute the RF signal and report a fault. The details of the fault can be accessed
via remote communication.
The M&C is also capable of acting as a controller in a 1:1 redundant system. When configured as
the back-up SSPA in such a system, it communicates with the other SSPA and toggles the
waveguide switches as necessary.
1.4.5 LNB Operation
Either LPOD package style may be ordered with an optional internal 10MHz reference and Low
Noise Block (LNB) converter bias tee. With these options installed, the user has control of the
bias tee enable (LNB On/Off) as well as the DC bias voltage (On/Off).
1.4.6 Power Supply
The LPOD features a power supply that is power factor corrected. It supplies several voltages
necessary for the unit to operate:
• The 10V power supply output state is controlled by circuitry within the RF module. If the RF
module does not have the –5.8V supply for any reason, it will not allow the 10V power
supply to turn on. This protects the power transistors within the RF module from failure due
to improper power supply sequencing.
• The +24V output powers the cooling fans, is the source of power for waveguide switching
when the SSPA is used in redundant configurations, and is dropped to +22V for LNB bias.
• The +5.8V, -5.8V, +7.8V and +13.5V outputs are used to operate the M&C board and other
overhead functions.