Calibration The Frequency (Approximate) - Icom IC-7851 Instruction Manual

16
MAINTENANCE

■ Calibration the Frequency (approximate)

A very accurate frequency counter is required to cal-
ibrate the frequency of the transceiver. However, a
rough check may be performed by receiving radio sta-
tion WWV, WWVH, or other standard frequency sig-
nals.
CAUTION: The transceiver has been thoroughly
adjusted and tested at the factory before being
shipped. You should not have to re-calibrate it.
q Push
the Mode key [SSB]
w Hold down [PBT CLEAR] for 1 second to clear the
PBT setting and make sure that the RIT/∂TX func-
tion is not activated.
e Set the frequency to the standard frequency station
minus 1 kHz.
• When receiving WWV or WWVH (at 15.00000 MHz) as
a standard frequency, set the operating frequency for
14.99900 MHz.
• Other standard frequencies can be used.
r Push [EXIT/SET] several times to close a Multi-
function screen, if necessary.
t Select the "Calibration Marker" item in the Display
set screen.
SET [F-7]  OTHERS [F-5] 
y Rotate [MAIN DIAL] clockwise to turn the calibra-
tion marker ON.
u Push [EXIT/SET] once to return to the
menu screen.
i Select the "REF Adjust" item in the
screen.
SET [F-7]  ACC [F-2] 
o Rotate [MAIN DIAL] to adjust for a zero beat with
the received standard signal as shown at left.
• Zero beat means that two signals are exactly the same
frequency, resulting in a single tone being emitted.
!0 Turn the calibration marker OFF in the Others set
mode.
!1 Push [EXIT/SET] twice.
• Exits the Set screen.
to select USB mode.
Calibration Marker
Set mode
ACC set
REF Adjust
(F) Function keys [EXIT/SET] [MAIN DIAL]
• Calibration Marker item
• REF Adjust item
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