Comtech EF Data PCB-4300 - Manual (Page 39)

PCB-4300 1:2 Phase Combiner Revision 2
Operation and Adjustment Procedures MN/PCB4300.IOM
3–9
Observe the following:
Step Procedure
7 Attach one channel of the power meter to the Combined Output Power Test Coupler
(refer to Figure 3-1). Attach the second channel of the power meter to the “Wasted”
Power Test Coupler. Make sure the power meter has been appropriately calibrated to
include the respective correction factors of the test port couplers.
Note: If only one power meter is available, it may be alternately switched between the
Combined Output Test Coupler and the Wasted Test Coupler. It is suggested to start
with it at the Wasted Test Port as the power level at this port will be more sensitive to
adjustment.
8 Align the phase between SSPA#1 and #2:
• First, execute serial remote command FRC=12.
• Referring
to Figure 3-4, use the provided tool to loosen the locknut on the
phase shifter for path 1-2. Slowly turn the phase shifter with the screwdriver
while viewing the Combined and Wasted Power readings. For single frequency
alignment, the optimum setting is when the Combined level is maximized and
the Wasted level is minimized.
Note: For single frequency operation, (a) the difference between Combined and
Wasted Power levels will be 15-25 dB or more, and (b) there may be two different
positions of the phase shifter which give good results.
9 Align the phase between SSPA#3 and #2:
• First, execute serial remote command FRC=23.
• Referring
to Figure 3-4, adjust the phase shifter for path 2-3 as was done for
path 1-2 in Step 8.
10 After aligning paths 1-2 and 2-3 per Steps 8 and 9, execute serial remote command
FRC=13 to combine SSPAs #1 and #3. The Combined and Wasted level ratios should
be similar to those for the other paths mentioned above. Then:
• Perform any necessary fine adjustments, toggling between all three paths until
satisfactory performance is achieved.
• Tighten all phase shifter adjustment nuts with the provided socket.
• Replace the cover over the access hole.
Note: The Wasted Power Level is more sensitive, but optimizing it beyond reasonable
values has a diminishing effect on the desired Combined Output Power.