Kenwood TS-990S - Manual (Page 271)

18-1
18 TROUBLESHOOTING
Index Contents
CALIBRATING THE INTERNAL REFERENCE
FREQUENCY
The internal reference frequency of the transceiver was
properly calibrated at the factory. However, if the reference
frequency needs to be calibrated due to any reason such
as use across the ages, the internal reference frequency
can be calibrated by receiving the standard wave signal
such as VVWH (Hawaii), VVH (Colorado), BPM (Xian), or
others.
At first, follow the procedure described below to enable
the transceiver to receive the standard wave signal. The
procedure below describes the procedure when the pitch
frequency is 700 Hz.
[CW/CW-R] [RIT]
[VOX/SEL] [AF](M) [CW PITCH]
[HI/SHIFT]
[LO/WIDTH]
1 Press [CW/ CW-R] to select CW mode.
2 Press [RIT] to disable the RIT function.
The "RIT" LED turns Off.
3 Press [VOL/SEL] to enable the break-in.
• If the semi break-in is enabled, press [VOX/SEL] to disable
the semi break in.
• If the full break-in is enabled, press [VOX/SEL] to disable
the full break in.
• The "VOX" LED turns Off.
4 Rotate the AF control to select the 12 o'clock position.
5 Rotate the CW PITCH control to adjust the pitch to be
legible.
You can rotate the CW PITCH control until the pitch
frequency, displayed on the sub-scope center with the sub-
screen, reaches 700 Hz.
6 Rotate the LO/WIDTH control or the HI/SHIFT control.
You can rotate the HI/SHIFT control until the shift frequency
(SHIFT), displayed on the sub-scope with the sub-screen,
reaches a value of 0, and the LO/WIDTH control until the
bandwidth (WIDTH) reaches a value of 1000.
SUB-SCREEN
Note:
◆ Refer to "CONFIGURING THE REF I/O CONNECTOR" for the
configuration of the REF I/O connector. {page 16-22}
CALIBRATION PROCEDURE
After the calibration is completed, follow the procedure
below to configure the internal reference frequency.
[F1] [F7]
F[ADV.]
[ESC] [AF](M) Tuning (M)
[MULTI/CH]
[MONITOR]
1 Receive a standard wave signal on the main band.
To receive the 10 MHz standard wave signal, rotate the
Tuning control to select exactly "10.000.00".
The 700 Hz beat sounds.
f
AF
= f
reference
+ 700
[Hz]
x
f
display [MHz]
15.6
[MHz]
f
reference Shifts from Reference Frequency
The received beat can be audible on the CW pitch frequency.
2 Press [ADV.] (F) from the Menu screen to open the
Advanced Menu screen.
3 Access Menu 05, "Reference Oscillator Calibration".
4 Press [SELECT] (F4) to allow editing of the parameter
box.
5 Hold down [CAL.T] (F7).
The 700 Hz sidetone for calibration is generated. The double-
beat occurs due to the difference of two frequencies by the
sidetone and the received audio crossing each other.
If the double-beat cannot be heard clearly, rotate the AF
control to adjust the received audio level or the MONITOR
control to adjust the sidetone audio level.
f
sidetone
= 700
[Hz]
8
[ppm]
‒+ (700 0.006
[Hz]
)
‒+