Radio Shack HTX-400 Service Manual page 12

2) TRANSMITTER SECTION
STEP SETTING
1 RF Power stage ;
Mode : Transmit
Volume : Optional
Squelch : Optional
Frequency : 445.50MHz
2 Second harmonic check ;
Mode : Transmit
Volume : Optional
Squelch : Optional
Frequency : 445.50MHz
3 Frequency check ;
Mode : Transmit
Volume : Optional
Squelch : Optional
Frequency : 445.50MHz
4 MAX deviation check ;
Mode : Transmit
Volume : Optional
Squelch : Optional
Frequency : 445.50MHz
Modulation frequency :
(300Hz-3KHz)
3) RECEIVER SECTION
STEP SETTING
1 RX sensitivity ;
Mode : Receiver
Volume : Half clockwise
Squelch :
Turn to counterclockwise
CH Selector : 1
SSG : 1KHZ AF
3KHZ DEV.
0.22¥ ì V
Frequency : 445.50MHz
CONNECTION
Connect dummy
load and RF power
meter to the external
ANT-jack on the
Set
(Figure 2)
Connect RF power
meter with dummy
load to spectrum
analyzer through
coupler/-40dB atten.
to EXT-ANT. Jack
on the set
(Figure 3)
Connect dummy
load and frequency
counter through
coupler to RF power
meter.
Also connect power
meter to EXT-ANT.
jack on the set.
(Figure 4)
Connect dummy
load and modulation
meter through
coupler to RF power
meter.
Also connect power
meter to EXT-ANT.
jack on the set.
(Figure 6)
CONNECTION
Connect RF signal
Generator to external
ANT. Jack. Connect
SSVM, Sinadder and
Distortion meter
across EXT-Speaker
out jack with 16¥ Ø
dummy load
(Figure 5)
11
ADJUST ADJUST FOR
RV-101 Adjust for max.
indication on the
power meter
(300mW¡ ¾ 5 0mW)
At no modulation,
harmonic freq.-spectrum
suppression of the
2nd harmonic freq.
level must be lower
than 45dBc.
Check for the other
Frequency
Make sure that the
indication of the
transmitter freq. Is
146.50MHz¡ ¾ 5 PPM
on the frequency
counter.
RV-802 When the deviation
shows 3KHz, increase the
input of audio generator
up to 20dB. It is max
deviation value, which is
adjusted by 20KB
Semi Volume at RV802.
Swing the frequency of
audio generator
(300Hz-3KHz) and check
if the Peak FM Deviation
is within 5.8¡ ¾ 1 .0KHz
Spec.
ADJUST ADJUST FOR
T401 Adjust the parts
of tuning circuitry
for 12dB SINADDER