SG-2000 MANUAL
159
The SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA
©1995, SGC, Inc.
TEL: (206) 746-6310 FAX: (206) 746-6384
23.1.20
Carrier Insertion Adjustment
Note: The SG-2000 produces A3A, A3H modes of transmit by inserting a 10.7
MHz carrier through the Base pin of Q102 at levels of -14 dB and -2.5 to -4.0 dB
Turn the radio on in Receive, 8.0 MHz, A3A, USB and have a 50 ? dummy load
connected to RF Out from the Exciter.
Key the radio in transmit and adjust R337 to get a value of 520 ±20 mVpp on
the Collector pin of Q103
Change the radio to 2.0 MHz, A3H, USB
Key the radio in transmit and adjust R337 to get a value of 820 ±20 mVpp on
the Collector pin of Q103
23.1.21
30 MHz Low-Pass Filter Adjustment
Turn the radio on in receive, 30.0 MHz, CW, USB and connect a 50? dummy
load to the Exciter RF Out (J102).
Key the radio in transmit and adjust L108, L109 and L110 to maximum signal
on the Collector pin of Q103
23.1.22
ALC Check
Connect J102 on the Excitor (Transmit Out) to J1 on LPA (Transmit In) and the
output of LPA to a 50? dummy load.
Turn R41 and R42 on the LPA fully clockwise.
Turn R121 on the Exciter fully counterclockwise.
Set the radio to 8 MHz, CW, USB, Hi (high power).
Key the radio in transmit. Adjust R121 to get 200 W RF Out. Do not keep the
radio at 200 W for more than 5 seconds. Adjust R41 to get a reading of 150 W RF
Out.
Change mode of transmit to Lo (low power) and key the radio and adjust R42
on the LPA board to achieve a reading of 50 W RF Out.
If test fails, verify the following levels:
IC208 pin 2 = 2.6 ± .1 VDC HI power without ALC (R41, R42 fully
clockwise), 200 W FR Out
IC208 pin 2 = 2.9 ±.1 VDC at LO power