Garmin APOLLO GX SERIES Service Manual - page 89
Garmin AT
Rev --
© 2004 Garmin AT
GX Service Manual
7-51
Receiver Sensitivity
Step
General Instruction
Specific Instructions
Expected Results
1 Set
all
test
equipment as
specified in Test
Equipment Setup on
page 7-17.
2
Sig. Gen. Mod Lvl.
to 30%.
Amplitude to 1000
µV.
On the HP8920:
1. Set AFGen1 to AM 30%.
2. Set AMPLITUDE to 1000
µV.
3. Set Ext. Load R 4 ohms.
3
Move test cable.
On the test box, connect the
HP8920 audio in cable to SPKR
OUT.
4 Adjust
volume
control on Comm
radio for 12 W.
On the Comm radio, adjust the
volume control until the AC Level
reads 12 watts.
≥12 watts output into 4 ohm
load (mounted in test fixture) at
a volume level from 0 to 12
watts.
5
Open squelch.
On the Comm radio, pull the
Squelch knob out (disable
squelch).
6
Get SINAD reading
and record.
On the HP8920:
1. Set the value field in the
SINAD meter reading to
average (AVG) at 10 dB.
2. Set AMPLITUDE using the ↓
down arrow until the SINAD
meter reads 6 dB SINAD.
3. Record
AMPLITUDE.
<2 µV (hard) for 6 dB S+N/N
with 30% modulation at 1000
Hz modulation.
7
Repeat.
Repeat step 6 for 118.00 MHz
and 136.975 MHz.