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GNS 400W Series Maintenance Manual
Page 4-23
190-00356-05
Rev. A
4.5.5 Test
Procedures
General Notes
Unless otherwise specified, the receive channel must be set to 127.000 for 25 kHz channel mode,
and 127.005 kHz for 8.33 kHz channel mode. Where no channel mode is specified, tests are
performed at 127.000 mHz, 25 kHz channel mode. The 8.33 kHz channel mode uses a channel ID
that does not match the actual operating frequency. Channel ID is used in this manual to specify
test frequency. Unless otherwise specified, the receive channel must be set to 127.000 mHz. The
table below shows the channel ID and frequency for the standard receiver test channels.
25 kHz Channel 8.33 kHz Channel
Channel Frequency
118.025 118.030 118.025
mHz
127.000 127.005 127.000
mHz
136.975 136.980 136.975
mHz
NOTE
The audio compressor must be disabled unless otherwise specified.
The audio output must not vary more than 6 dB, when the level of an RF signal modulated 30% is
held constant at 1000 µV and the modulation frequency is varied over the audio-frequency range
of 350-2500 Hz. The audio output must be measured in 25 kHz channel mode at 350, 1000, 1500,
and 2500 Hz and in 8.33 kHz channel mode at 350, 1000, 1500, and 2500 Hz.
The audio frequency response above 2500 Hz must decrease, and at all frequencies above 4000
Hz it must be at least 18 dB below the output obtained at 1000 Hz. Measure in 25 kHz channel
mode and in 8.33 kHz channel mode.
Comm Board Power Input Check
The comm board operates according to the power requirements listed in Table 4-2. Replace the
main board if any voltage on the comm board is not within tolerance. Replace the comm board if
excessive current is noted.
Connector/
Pin
Voltage
(V)
Tolerance
(V)
Max Current
Conditions/
Remarks
J2 Pin 11 & 12
+11 to +33
15.0 mA
Receive Mode
J2 Pin 11 & 12
+13.75
(14/28V 10 watt
units only)
±
0.2 V
6.0 A
TX Mode
J2 Pin 11 & 12
+27.5 (28V 10
watt units only)
±
0.4 V
3.0 A
TX Mode
J2 Pin 11 & 12
+27.5 (16 watt
units only)
±
0.4 V
3.0 A
TX Mode
Table 4-5. Comm Board Power Requirements