AMX TXC16 Plus Specifications download pdf (Page 187)

SG-2000 MANUAL 180

The SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA

Adjust the coils in the selected filter for lower current and higher RF Out,

especially in the end of band frequencies.

If RF Out from LPA is less than 140 W, increase the RF Out from the Generator

(to no more than +3dB) until the power out is 140-160 W.

Note in the LPA Alignment form:

• RF In level from RF Generator (between -1 to +3 dBM)

• RF Out level from LPA (between 140-160 W)

• F1 and F2 current on corresponding amp meter

• Power Supply current

Repeat above for all frequencies listed in the Filter Band Table above, making

sure the proper filter has been selected manually from the Test Box before each

frequency is tested.

23.2.7 ALC Check

Automatic Level Control (ALC) consists of sensors T13, T14, amplifiers IC2 A,

C and D, buffer IC2 B on the LPA and IC208 on the Exciter.

Preset levels for Low and High power out are adjustable form R41 and R42 and

control the amount of signal the IC8 attenuator on the Exciter lets reach the

LPA, therefore the amount of RF Out reaching the antenna.

On the Test Box, turn SW3 to RCV and turn power on (SW1).

Change modes of power from SW5, adjust R41 and R42 and check the voltage

on TP1 on Test Box as follows:

Mode R41 and R42 R41 and R42

(SW5) Fully Clockwise Fully Counterclockwise

High (L5=off) 0.08 ±0.02 VDC=V1 6.3 ± 0.2 VDC

Low (L5=on) 4.8 ±0.2 VDC=V2 6.3 ±0.2 VDC

Note: L5 on Test Box will indicate that Q14 on LPA is biased for not

conducting, and corresponds to Low power mode.

Switch RF In to 8.0 MHz and select the appropriate filter on the LPA

Turn R41 and R42 fully clockwise.

Adjust RF In from RF Generator for 150 W RF Out from LPA, in transmit into

50 ? dummy load antenna.

With SW5 on High power, switch to transmit and note the voltage level at TP1

on Test Box. Write this value as V1 on the test form.

With SW5 on Low power, switch to transmit and note the voltage level at TP1

on Test Box. Write this value as V2 on the Test form.

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AMX TXC16 Plus Specifications Page 187