Comtech EF Data XPA-200 - Manual (Page 33)

XPA200-7984-I-OPT1, X-Band SSPA Installation
XPA200-7984-I-OPT1, Rev.2 2-5
2.3.1 Redundant Operation and Setup
The system can operate in a standard 1:1 redundant
configuration by choosing VPC position 1 (SSPA A to antenna) or 3
(SSPA B to antenna) on the Mitec 2723B. For example, if the Mitec
2723B was set to run in Automatic mode and SSPA A was normally
operating to the antenna (VPC position 1), a fault on SSPA A would
cause the system to immediately switch to postion 3, or SSPA B to
antenna.
Each SSPA may have slightly different gain values. A
procedure to equalize gain and output power between SSPA A and SSPA
B for redundancy operation is described below. The output powers
from SSPAs A and B are first equalized by measurements at the load
port before switching power to the antenna port.
A. To set the output power of SSPA A:
1. Mute SSPA B via remote or front panel controls.(To
prevent unwanted power from SSPA B going to antenna.)
2. Set VPC to position 3 (B to antenna, A to load).
3. Connect a power meter to the Mitec calibrated load
measuring port (see 2723B test data for exact calibration
data). Adjust output power of SSPA A to desired level by
adjusting input RF power or by using the SSPA A attenuation
setting.
B. To set the output power of SSPA B:
1. Mute SSPA A via remote or front panel controls.(To
prevent unwanted power from SSPA A going to antenna.)
2. Set VPC to position 1 (A to antenna, B to load).
3. Connect a power meter to the Mitec calibrated load
measuring port (see 2723B test data for exact calibration
data). Adjust output power of SSPA B to desired level
(usually the same as A) by adjusting input RF power or by
using the SSPA B attenuation setting.
C. Choose the unit desired to be on-line.
1. Mute both units to prevent unwanted power from going to
the antenna.
2. Choose SSPA A (position 1) or SSPA B (position 3) for
operation to the antenna. The other unit will be sent to
the load.
3. Set the Mitec unit in Automatic mode and un-mute the
SSPAs.
4. Verify proper output power going to antenna by
connecting a power meter to the Mitec Antenna Forward power
measuring port (see Mitec test data for calibration factor).