Vertex Standard VX-5500L Service Manual page 23

Alignment
Before beginning, connect the transceiver and PC
using the CT-71 programming cable, and download
the EEPROM data from the transceiver to the com-
puter.
Store this data in a disk file so that it can be saved
and retrieved later. Using the table below, program
the channel, CTCSS, and DCS alignment settings for
your transceiver version. Upload this file to the trans-
ceiver.
Note: Signal levels in dB referred to in this proce-
dure are based on 0 dBµ = 0.5 µV (closed cir-
cuit).
Caution:Do not connect the audio output line to
ground, and be certain that the speaker has
adequate capability to handle the audio
output from the radio.
Because of the bridge audio amplifier cir-
cuit used in the radio, it is necessary to con-
struct and use a simple audio load test
adapter as shown in the schematic diagram
below, when conducting receiver alignment
steps.
3.5 PLUG
2-ohm
10W
2-ohm
10W
(4-ohm Dummy Load)
AF Test Adapter Schematic
Alignment Channel Frequencies
Frequency
Channel
(simplex)
CH1 37 MHz
CH2 43.49 MHz
CH3 43.5 MHz
CH4 50 MHz
CH5 43.5 MHz
CH6 43.5 MHz
5-2
Attenuated
Test Output(1/2)
GND
470uF
CTCSS DCS
Encode Encode
None None
None None
None None
None None
151.4 Hz None
None 023
PLL & Transmitter
Set up the test equipment as shown for transmit-
ter alignment.
Maintain the supply voltage at 13.8 V DC for all
steps.
Inline Wattmeter
RF Sampling
Deviation Meter
Coupler
CT-71 connection
Cable
Frequency
Counter
PLL VCV
Connect the positive lead of the DC voltmeter to
test point TP1010 (VCV) on the Main Unit, as in-
dicated in the figure, and connect the negative lead
to chassis ground.
Set the transceiver to the high band edge fre-
quency channel (CH4), then key the transmitter,
and adjust T1006 on the Main Unit for 7.0 V ±0.1
V on the voltmeter.
Adjust T1005 on the Main Unit for 7.0 V ±0.1 V
on the voltmeter.
Select the band center frequency channel (CH2)
and Adjust T1011 on the Main Unit for 7.0 V ±0.1
V on the voltmeter.
Next select to the low band edge frequency chan-
nel (CH1) and confirm the VCV is 3.1 V ±0.3 V on
the voltmeter.
Select the band center frequency channel (CH3)
and confirm the VCV is 3.75 V ±0.3 V on the volt-
meter.
Select the low band edge frequency channel
(CH3), than Key the transmitter, and confirm the
VCV is 1.7 V ±0.3 V on the voltmeter.
PLL Reference Frequency
With the wattmeter, dummy load and frequency
counter connected to the antenna jack.
Select the high band edge frequency channel
(CH4), and select the "low" power output level.
key the transmitter and adjust TC1001 on the
Main Unit, if necessary, so the counter frequency
is within 100 Hz of the channel center frequency
for the transceiver version.
RF Signal
Generator
Transceiver
Power Supply
P C
13.8V DC
COM port