Motorola RF Amplifier quick start Thermal Drive Unit, Automatic Drive Unit

STARLINE5

If necessary, to achieve the gain specification, you can use the interstage pad or output pads to reduce the gain of the amplifier. However, this will affect amplifier performance. Output padding degrades the station distortion performance while having minimal effect on the carrier-to-noise (c/n) performance. Interstage padding is the opposite and therefore has little effect on distortions but degrades the c/n performance. In general Motorola recommends that you pad to the amplifier gain specification on the output (where possible). However, if you are unsure about the optimal padding technique for your system, split the required padding evenly between the interstage and output pad(s).

It is recommended that you contact Motorola’s TRC or your account representative for more specific information regarding use of the interstage and output pads.

Thermal Drive Unit

To use the thermal drive unit (TDU):

1Place the jumper on the TDU to the LOW, MEDIUM, or HIGH position to specify the amount of cable for which the TDU compensates at the highest frequency preceding the amplifier station.

Low = 0 dB to 15 dB, medium = 15 dB to 30 dB, and high = 30 dB or more of cable.

2Position the drive control select jumper temporarily in the MAN position and perform the complete procedure described in Manual Gain Control if not already completed.

3Position the drive control select jumper to DRIVE UNIT.

4Connect a signal-level meter to the FWD OUT test point and tune the meter to the high band-edge carrier.

5Turn the thermal level potentiometer on the TDU fully clockwise and then reduce to obtain the level stated in Step 7 under Manual Gain Control.

Automatic Drive Unit

To use the automatic drive unit (ADU):

1Position the drive unit select jumper temporarily to the MAN position and perform the complete procedure described in Manual Gain Control if not already completed.

2Verify that the frequency stamped on the ADU control unit is the same as the system pilot frequency.

The pilot frequency is a CW pilot or available NTSC television channel not scrambled using sync suppression.

3Position the drive control select jumper to DRIVE UNIT.

4Connect a signal-level meter to the FWD OUT test point and tune the meter to the high band-edge carrier.

5Turn the auto level control potentiometer (ADU) fully clockwise and then reduce to obtain the level stated in Step 7 under Manual Gain Control.

RF Amplifier Quick Start Guide