Garmin APOLLO GX SERIES, Service Manual

Page: 81 / 166

Garmin AT Rev --
© 2004 Garmin AT GX Service Manual 7-43
Step General Instruction Specific Steps Expected Results
22 Check to see if
emission meets
specification. On the test box, press the PTT
switch to TX. The Lvl field should read ≥ 25
dB down minimum from marker
to right edge of screen (typical
> 52 dB down).
23 On the test box, press the PTT
switch to RX.
24 Add or subtract 25.0
kHz to get new
center freq. Add 0.025 MHz for the upper
side band, or
Subtract 0.025 MHz for the lower
side band.
Example: 127. 0.025
= 127.524712 upper side band.
Example: 127.499639 - 0.025 =
127.4746390 lower side band.
25 Enter the results as the new
center frequency.
26 Check to see if
emission meets
specification. On the test box, press the PTT
switch to TX. Lvl field should show ≥ 25 dB
down minimum across the
entire screen (typical > -52 dB).
27 On the test box, press the PTT
switch to RX.
28 Add or subtract 62.5
kHz to get new
center freq. Add 0.0625 MHz for the upper
side band, or
Subtract 0.0625 MHz for the
lower side band.
Example: 127. 0.0625
= 127.562139 across the entire
screen (typical > -52 dB).
29 Enter that as the new center
frequency.
30 Check to see if
emission meets
specification. On the test box, press the PTT
switch to TX. Lvl field should show ≥ 35 dB
down minimum across the
entire screen (typical > -52 dB).
31 On the test box, press the PTT
switch to RX.
32 Add or subtract 500
kHz to get new
center freq. Add 0.500 to recorded center
freq. Example: 127. 0.500
= 127.999636 upper side band.
Example: 127.499639 - 0.500 =
126.9996390 lower side band.
33 Enter that as the new center
frequency.
34 Check to see if
emission meets
specification. On the test box, press the PTT
switch to TX. Lvl field should show ≥ 52 dB
down minimum across the
entire screen (typical > -52 dB).
35 On the test box, press the PTT
switch to RX.