Document No. 8128000560
Software Revision – N1B (07 Oct 04)
7-30
RT-9000 B
7.3.3.1.3 Transmit BITE (‘TX BITE’)
Overview
Transmit BITE primarily tests the RT-9000 B Transmitter modules but also performs a brief Antenna System
test. An improperly operating Antenna System can cause false Transmit BITE test results. This is the primary
reason Antenna System testing is included in the Transmit BITE test routine. In addition to internal test use,
this same valuable Antenna status information is also passed directly to the User.
Certain Transmit BITE tests are performed at eight (8) selected test frequencies. These test frequencies were
selected to thoroughly exercise all RT-9000 B Transmitter modules as well as the station Antenna System.
These test frequencies are listed in the following chart.
Transmit BITE
Test Frequencies
(MHz)
1.75 7.75
2.75 10.75
3.75 16.75
5.75 25.75
The type of Antenna tests performed will depend on the type of Antenna the station is using. Antennas are
generally either Broadband or Non-Resonant types. The following is a brief discussion of these antenna types
and testing.
A Broadband Antenna operates over a wide frequency range and is usually designed for a 50-Ohm input
impedance. This allows the Antenna to be directly fed from the Transmitter using 50-Ohm coaxial cable. This
Antenna type does not require an Antenna Coupler. Antenna testing consists of performing a VSWR test at
all eight (8) test frequencies.
A Non-Resonant Antenna may also operate over a wide frequency range but will have large input impedance
variations. These variations prevent the Antenna from being directly fed from the Transmitter using coaxial
cable. An Antenna Coupler must be used to match the Antenna’s impedance to the Antenna Coupler’s 50-
Ohm input impedance. 50-Ohm coaxial cable can then be used to connect the Transmitter to the Antenna
Coupler’s input. Antenna testing consists of performing a “Tuning Test” at all eight (8) test frequencies.
When a system contains an external Linear Power Amplifier and is using a Broadband Antenna, the same
tests are performed as without the Linear Power Amplifier. The external Linear Power Amplifier is always
switched it out of the system (or bypassed) during Transmit BITE testing. This effectively connects the RT-
9000 B Transceiver directly to the station Antenna. In this way, the external Amplifier is never involved in the
Transmit BITE test process.
Systems equipped with an external Linear Power Amplifier but using a Non-Resonant Antenna, of course,
must use an Antenna Coupler. With this system configuration, the Linear Power Amplifier is also switched out
during Transmit BITE. This effectively connects the RT-9000 B Transceiver to the Antenna Coupler input that
normally is connected to the Linear Power Amplifier output.
The following two (2) procedures describe how the Transmit BITE (‘TX-BITE’) test routine operates when
using either Broadband or Non-Resonant types of Antennas.
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