Harris ZX10, Техническое руководство

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12/20/11 888-2595-001 5-25
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WARNING: Disconnect primary power prior to servicing.
Section 5 Maintenance and Alignments
ZX Series
STEP 2
Press OFF button to switch transmitter off.
STEP 3
Open amplifier front door.
STEP 4
Locate POWER LIMIT - REV potentiometer on upper edge of
transmitter controller board.
STEP 5
Disconnect transmission line from transmitter output.
STEP 6
Press ON pushbutton to turn transmitter on.
STEP 7
Power should increase to a level equal to 2.5% of forward power if
initial factory adjustment has not been changed.
STEP 8
Adjust potentiometer to limit reverse power to desired foldback level,
typically between 1% and 4% of forward power.
STEP 9
Switch transmitter off and restore all equipment to original condition.
STEP 10
Procedure complete.
5.4.8 Set User Reverse Power Foldback Threshold
(ZX7.5, ZX10)
The procedure to set the reverse power foldback threshold is slightly different for larger
transmitter models in that a false reading of high reverse power can be generated at the
system level by swapping the ports on the REVERSE METER directional coupler at the
transmitter RF output. This facilitates setting or checking the reverse foldback
threshold without actually disconnecting the transmitter output to create high levels of
true VSWR.
Tools Required:
Fine adjustment screwdriver
STEP 1
Lower transmitter forward power via controller POWER LOWER
button to a level close to desired reverse foldback threshold. (e.g. 2.5%
of nameplate power)
STEP 2
Open transmitter rack rear door.
STEP 3
Locate REVERSE METER directional coupler section at final
transmitter output.
STEP 4
Swap REVERSE METER sample cable and SMA load between two
ports of coupler section. System reverse meter cable is now connected
to forward port of coupler. Reverse meter of system metering assembly
should read a level comparable to forward power (…because it is now
sampling forward power).