Vertex Standard VX-5500L, Service Manual

Page: 25 / 94

5-4
Alignment
Transmitter Deviation
The following modulation parameters can be ad-
justed from the computer by utilizing the Alignment
Software. Refer to the onboard help of the Alignment
Software Manual for details.
Microphone Audio Modulation Level
U
Select the band center frequency channel (CH4),
and select the “low” power output level.
U
Adjust the AF generator for 50 mV (–30 dBm) out-
put at 1 kHz, as applied to the microphone jack.
U
Key the transmitter and adjust “
MAX Dev
“ for
maximum deviation of 4.2 kHz ± 0.2 kHz as indi-
cated on the deviation meter.
CTCSS Modulation Level
U
Select the “low” power output level.
U
Select the band center frequency channel (CH5),
with 151.4 Hz CTCSS encode, and reduce the AF
generator injection to zero.
U
Key the transmitter and adjust “
CTCSS Dev
“ for
CTCSS deviation of 0.7 kHz ± 0.1 kHz as indicated
on the deviation meter.
DCS Modulation Level
U
Select the “low” power output level.
U
Select the band center frequency channel (CH6),
with 023 DCS code, and reduce the AF generator
injection to zero.
U
Key the transmitter and adjust “
DCS Dev
“ for DCS
deviation of 0.7 kHz ± 0.1 kHz as indicated on the
deviation meter.
Receiver
The sensitivity parameters can be adjusted from
the computer by utilizing the Alignment Software.
Refer to the onboard help of the Alignment Software
Manual for details.
U
Set up the test equipment as shown for receiver
alignment, and install the audio test adapter.
50-Ohm
Dummy Load
RF Signal
Generator
Power Supply
13.8V DC
AF Generator
SINAD
Meter
AF Test
Adapter
AC Volt
Meter
Inline
Wattmeter
Deviation
Meter
RF Sampling
Coupler
CT-71
Connection
Cable
Frequency
Counter
Transceiver
13.8
U
With the transceiver set to the low band edge fre-
quency channel (CH1), and with the RF signal
generator tuned to the same frequency, set the
generator for ±3.0 kHz deviation with 1 kHz tone
modulation at the antenna jack.
U
Adjust T1001 ~ T1004 on the Main Unit for opti-
mum SINAD, reducing signal generator output
level as necessary for proper meter deflection.
U
Select to the band center frequency channel (CH3),
and the final signal generator level should be less
than –6.0 dB
μ for 12dB SINAD.
U
Select to the high band edge frequency channel
(CH4), and the final signal generator level should
be less than –6.0 dB
μ for 12dB SINAD.
U
Select to the low band edge frequency channel
(CH1), and the final signal generator level should
be less than –5.0 dB
μ for 12dB SINAD.