Installation Procedure - Comtech EF Data SDM-650B Installation And Operation Manual

SDM-650B Satellite Modem
E.2.2 Installation Procedure
Refer to Figure E-2 as needed. To install the AGC interface option:
1. Remove the rear panel of the modem.
2. Using the hardware provided, install the AS/0769 board to the modem
3. Attach the following wires to the motherboard:
4. Adjust R4 to achieve a reading of approximately 4.33K
5. Power up the modem.
6. Adjust R5 to achieve a reading of approximately +5.75V at the right side of R2.
7. Measure the voltage at pin 1 of the 9-pin connector:
8. Install the new back panel (refer to Figure E-1).
Rev. 5
motherboard between CP1 and CP2 (IF OUT and IF IN). (Refer to Figure E-1.)
a. E1 ⇒
GND
b. E2 ⇒
+12V
c. E3 ⇒
AGC J3, B4
d. E4 ⇒
-12V
Refer to Figure E-2.
pin 2 (refer to Figure E-3).
a. To achieve the minimum AGC voltage output at pin 1, set the modem input
to -55 dBm and verify the reading is 0V.
b. To achieve the maximum AGC voltage output at pin 1, set the modem input
to -30 dBm and verify the reading is 10V.
If minor adjustments are necessary, adjust the GAIN and OFFSET
potentiometers until both readings are correct.
AGC Interface
Ω between U1 pin 1 and
E–3