NGT—Checks and adjustments
NGT Transceiver System Technical Service Manual 185
Adjusting balance control
To adjust the balance control:
1 Connect setup as per the bias gain adjustment (see page 182, Adjusting the bias
gain).
1 Select test channel 21.
1 Connect the signal generator to provide single-tone audio (1 kHz) via the test unit to:
• the audio input on the 15-way GPIO connector on the junction box or 2012 RF
Unit (see Figure 40 on page 170), or
• the 2011 RF Unit via the NGT test handset (see Figure 41 on page 170)
1 Set up the spectrum analyser as follows:
1 Hold down PTT, then adjust the single-tone level for compression.
1 Adjust the sensitivity control on the spectrum analyser to set the tone at the top of
the screen.
1 Adjust the balance control (R253) for a minimum on 17.2 MHz.
1 Check that the level of the 2
nd
harmonic (17.2 MHz) is below 60 dB.
1 Release PTT.
ALTERNATIVE TEXT
Drawing 08-05415 or 08-05511 (sheet 1)
NOTE
The transceiver must be in Service mode to make this adjustment (see
page 154, Accessing Service mode).
Centre frequency 10 MHz
Frequency span 20 MHz (2 MHz per division)
Vertical level 10 dB per division
Sensitivity Depends on the signal level applied to the spectrum
analyser and requires adjustment when transmitting
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