Installation Manual

3
APPLICANT: LARUS CO.
FCC ID: LYA 9000
a. 4.5/10.7 MHz modulated telemetry/control signals to carry information: terminal
diagnostics and local/remote faults (transmit power level set).
b. –24/–48 VDC, 2A battery power supply line to the transmitter.
c. 140 MHz IF from the 140 MHz I/Q modulator/VCO from the Control Module to the
transmitter.
IF Amplifier Chain. Amplification, equalization, gain/level control and gain setting
takes place in the 140 MHz transmit IF amplifier chain. Equalization helps to reduce inter-
symbol interference thereby improving BER performance. The gain control helps to stabilize
the drive power at the 5.7 Ghz power amplifier input over the operating environment. The
gain setting is entered manually by the operator via keyboard. The accuracy of this
attenuator is about
∀
0.4 dB.
RF Amplifier Chain. This contains the 140 MHz to RF mixer/upconverter stage,
waveguide bandpass filter, transmit RF amplifier and diplexer. The upconversion is low side
LO injection. The RF amplifier provides linear gain and power level of nominal +23 dBm for
undistorted transmission at the output frequency. The waveguide filters provide the out-of-
band attenuation needed to suppress unwanted spurious: local oscillator leakage and all
other mixing/intermodulation products.
Diplexer. Additional filtering of the transmit signal and the required transmit-receive
isolation is provided by the waveguide diplexer according to the frequency plan shown in
Figure 1. The transmit spectrum at the diplexer port is shown in Figure 2.
Setting transmit power. The transmit power at the diplexer port is set with the
keyboard of the display terminal according to the desired EIRP. Nominal power at the
bulkhead is +23 dBm at –7 dB attenuator setting. As an example, for a 28 dBi antenna and
interconnecting cable loss of 1 dB, the EIRP is +23 -1 +28 = 50 dBm or 20 dBw (100 W).
The +23 dBm can be attenuated in 1 db steps. The value of attenuation can be
observed on a monitor display intended for remote reporting, status and control.
Setting the EIRP is the responsibility of customer, who installs the antenna and owns
and operates the system.
4. Receiver functional description.
Diplexer/RF filter. The received frequency is filtered and fed to the down converter,
contained in the RF module. The received RF spectrum at the diplexer output is as shown in
Figure 1. The purpose of the RF filters is to:
a. Filter out unwanted spurious products and responses (image response).
b. To provide the necessary transmit-receive isolation.
Up/Down Converter. This function is contained in the RF module. It provides LNA
preamplification and the translation from RF to the 70 MHz receive IF.