SG-2000 MANUAL
128
The SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA
©1995, SGC, Inc.
TEL: (206) 746-6310 FAX: (206) 746-6384
21.5
AM Filter Bypass
The SG-2000's normal range is from 1.6 to 30 MHz. To receive down into
the AM band, you will need to bypass the AM filter. To do this:
1.
Remove top cover by removing six 6-32 black Phillips head screws
that secure the cover to the SG-2000.
2.
Place radio with exciter PCB facing up.
3.
There is a long “L” shaped metal heatsink bracket located on the
left side of the exciter. On this bracket is the AM Filter PCB.
4.
On the AM Filter board, disconnect the gray coax cable going to the
RF-in jack and disconnect the short coax on the AM Filter into J101
on the exciter PCB. Tape up the short coax connector or remove the
AM Filter board entirely.
5.
Connect the long coax directly into J101 on the exciter PCB.
6.
Replace the top cover and secure with the six Phillips head screws.
Your SG-2000 will now receive down to 500 KHz.
21.6
Oscillator and Filter Operation
(
refer to block diagram J40100920)
Following is a list of the six major modules and their
descriptive functions:
(a)
Microprocessor assembly
(b)
11.94 Master oscillator with oven
(c)
VCOs
(d)
PLLs
(e)
Serial Logic Switches
(f)
Tone generator
Refer to Schematic Section at the end of this document.