Receiving W Eather Alert Tone Adjustment And Confirmation - Standard Horizon GX1250SA Service Manual

4.12 Receiving W eather Alert T one Adjustment and Confirmation
Alert sound is emitted when some specific urgent signal is
received on Weather Channel (Weather Alert). Weather Alert
Tone Scan operation is done only when GX1250SA is work-
ing on Memory Scan or P-Scan and Weather Channel has
been set in Scan Memory.
- Adjustment -
Figure 4-12
(a) Setup GX1250SA as shown in Figure 4-12. Press WX key
to set Weather Channel, then press Up/Down key to set
channel to WX10.
(b) Output 163.275MHz 20dBuV non-modulation signal from
Signal Generator.
(c) Adjust R109 to set frequency counter to 1045Hz.
- Confirmation -
(a) Set SG frequency to WX10 (163.275MHz), modulation
frequency to1050Hz, deviation to ±1.0kHz. Turn off SG
output. Then set output level to 20dBuV.
(b) Turn SQL volume clockwise to the end and press Scan
key to start Scan operation.
(c) Turn on SG output. Check that Scan operation doesn't
stop.
(d) Turn up deviation from ±1.0kHz and measure Weather
Alert sensitivity at modulation frequency of 1050Hz. Check
that Scan operation stops at WX10 and alert sound is
emitted. Also check that deviation is not over ±2.5kHz at
that time (Scan stops and alert sounds).
(e) Press WX key and check that alert stops and voice is
emitted from the speaker.
(f) Change modulation frequency to 1030Hz and repeat steps
2-4 then check that deviation if weather alert is activated
is higher (weather alert sensitivity is lower) than when
modulation frequency is 1050Hz.
Also change modulation frequency to 1070Hz and check
that deviation is higher than when modulation frequency
is 1050Hz likewise.
(If it doesn't pass the test above, re-adjustment has to be
done. Also, if weather alert sensitivity at 1050Hz is the same
as either 1030Hz or 1070Hz, re-adjustment is required.)
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Figure 4-13