User's Manual

351804-1 Rev. 100

COM5000-8 TECHNICAL MANUAL

≤ 5 feet coax

d. Key the system and observe the Wattmeter reading. The forward power should be close to 2000W

and the reflected power close to 200W.

By varying the RF drive level with the variable attenuator, adjust the reflected power read on the

Watt-Meter for 200W - the forward power reading should be close to 2000W.

If it is not possible to obtain the 200W there may be a number of reasons:

1. The VSWR ALC may be engaging too early (VR5)

2. Actual fault conditions

e. With 200W reflected power:

Measure the DC voltage at the junction of R96 and L1 and verify that the voltage is 1.27 - 1.31 V. If

not, there may be a problem in the Combiner module.

Then, if necessary:

1. Adjust VR3 for 1.16 VDC @ U31 pin 11

2. Adjust VR9 for a System Controller front panel REV PWR METER reading of 200W

Wattmeter

4381

50 Ohm, 4 kW Load/

Attenuator w.

Blower

8929-300

50 Ohm Load,

10 kW

Bird 8931

Transmitter

Directional

Coupler