Standard Horizon HX270S, Service Manual

Page: 10 / 28

10
Before Alignment
Press and hold in the [
] key and [
MEM
] key while
turning the transceiver on to enter the Alignment
Mode.
PLL Reference Frequency
Set up the test equipment as shown below for PLL
and Ttransmitter Section Alignment. Maintain the sup-
ply voltage at 8.4V DC for all steps.
Press the [
] or [ ] key to sect the display to “
rEF
.“
The transceiver now is in the PLL Reference Frequency
Alignment Mode.
Press the [ PRESET
] key to enable adjustment of the
PLL Reference Frequency.
Press the PTT key to cause the transceiver to transmit;
if necessary, press the [
] or [ ] key to adjust the
frequency to 155.500 MHz (±100 Hz).
Press the [ PRESET
] key to exit the PLL Reference Fre-
quency Alignment Mode.
Alignment
Squelch Threshold and Tight Squelch Adjustment
Set up the test equipment as shown below for Receiver
Section Alignment. Maintain the supply voltage at
8.4V DC for all steps.
Press the [
] key twice to set the display to “
tHL
.“
The transceiver now is in the Squelch Threshold Align-
ment Mode.
Set the RF signal generator output to 155.600 MHz, at
a level of –12 dBµ with ±3.5 kHz deviation with a 1
kHz audio tone.
Press the [ PRESET
] key to read the Squelch Thresh-
old data.
Press the [ H/L
] key twice.
Press the [ PRESET
] key to exit the Squelch Thresh-
old Alignment Mode.
Press the [
] key monentarily to set the display to
“
tI
.“ The transceiver now is in the Squelch Tight Align-
ment Mode.
Increase the RF signal generator output to –4 dBµ, then
press the [
PRESET
] key to read the Squelch Tight data.
Press the [ H/L
] key twice.
Press the [ PRESET
] key to exit the Squelch Tight
Alignment Mode.
PLL & T
RANSMITTER
S
ECTION
A
LIGNMENT
S
ETUP
Inline
Wattmeter
RF Sampling
Coupler
AF Signal
Generator
8.4 V DC
Regulated Power Supply
50
Dummy Load
Ω
Frequency
Counter
Frequency
Counter
HX27 0S
MIC Input
Pin 10 of J1008