SG-2000 MANUAL
150
The SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA
©1995, SGC, Inc.
TEL: (206) 746-6310 FAX: (206) 746-6384
23.1.6
Receive Sensitivity Check
The following describes the alignment of the receiving path on the exciter,
starting at RF In (J101) and finishing at pins 9 and 10 of J503/J504 where the
audio signal is passed to the SG-2000 head.
82 MHz filter calibration description. See diagram below:
This is a combination of two filters: one band-pass filter composed of T106-T108
coupled with a High-pass filter composed of L121-L127. The left side edge of
their graphed band pass coincide. The result is a band-pass filter with the limits
at 82 MHz and 86 MHz. The 82 MHz filter will be adjusted for a flat response in
the band 82-86 MHz by:
1) comparing within 1.5 dB the sensitivity measured at J301 RX Out for three
specific RF frequencies. These frequencies correspond with the positions of low,
middle, and high on the graphed band-pass characteristic of the 82 MHz filter.
2) connect the Spectrum Analyzer on points A and B at the ends of the 82 MHz
filter noted on the schematic, with the radio turned OFF. The filter will be
swept and should be adjusted as follows: