Alignment - Vertex Standard VX-520U Service Manual

UHF Transceiver Required Test Equipment
H IBM PC compatible computer
H
Vertex Standard VPL-1 Cable, or FRB-2 Service Kit, with
CE37 Channel Programming Diskette
H
Vertex Standard CN-1 BNC Adapter plug
H RF Signal Generator with calibrated output level at 1 GHz
H
Deviation Meter (Linear Detector)
H
AC Voltmeter
H
SINAD Meter
H
In-Line wattmeter with 5% accuracy at 1 GHz
H Regulated DC Power Supply adjustable from 4 to
10 V, 3 A
H 50-Ω Non-reactive Dummy Load: 10 W at 1 GHz
H
Frequency Counter: ±0.2 ppm accuracy at 1 GHz
H AF Signal Generator
H
DC Voltmeter: high impedance
Before beginning alignment, connect the transceiver and
PC using the VPL-1 Cable or FRB-2 Set as described in
the EEPROM Programming chapter, and download the
EEPROM data from the transceiver to the computer.
Then store this data in a disk file so that it can be up-
loaded when alignment is finished.
You should find the corresponding data file on the com-
puter disk for the transceiver version you are aligning, con-
taining channel settings for the high edge, middle and low
edge of the transceiver's frequency range in channels 1, 2
and 3, respectively. Up-load this file to the transceiver.
LOW BAND BAND CENTER
EDGE CH. (1)
450.0 MHz 460.0 MHz
HIGH BAND
CH. (2) EDGE CH. (3)
470.0 MHz
PLL & Transmitter
Set up the test equipment as shown for transmitter
alignment. Adjust the supply voltage to 7.2 V for all steps
where not specified otherwise.
Sampling
Coupler
50-ohm Inline
Dummy Load Wattmeter
Deviation
Freq. Counter
Meter
AC Voltmeter
PLL & TX Alignment Setup
PLL VCV (Varactor Control Voltage)
Ë
Connect the DC voltmeter between C2105 on the PLL
Unit and chassis ground.
Ë
Set the transceiver to CH 3 (high band edge), and ad-
just L2402 on the VCO Unit for 3.5 V ± 0.1 V on the
voltmeter.
Ë Transmit on the high band edge, and adjust L2406 for
3.5 V ± 0.1 V on the voltmeter.
Ë Set the transceiver to CH 1 (low band edge), and con-
firm the low-end VCV is more than 1.3 V while trans-
mitting, and also while receiving.
PLL Reference Frequency
Ë With CH 2 (band center) selected, key the transmitter
and adjust TC2101 on the PLL Unit, if necessary, so the
frequency counter displays the band center frequency
±300 Hz (for the version being aligned) when transmit-
ting.
L2402
L2406
C2105
PLL & Transmitter Alignment Points (I)

Alignment

ANT
AF Signal
Generator
AC Voltmeter
MIC
Regulated DC
7.2V PSU
VR3204
VR3201
VR3202
TC2101
15