Elecraft K144XV Manual - Manual (Page 19)

19
Frequency Calibration
There are two local oscillators in the K144XV that control the receive and transmit frequencies. One is active
from 144 to 146 MHz and the other is active from 146 to 148 MHz. Both oscillators must be calibrated to
provide an accurate frequency display across the band. The calibration is done by entering a frequency offset in
the K3’s configuration menu (this was done at the factory if you purchased your K3 with the K144XV already
installed).
Each K144XV is tested at the factory and offset data is printed on the K144XV module top cover label in the
following format:
OFFSETS 144 MHZ ± X.XX 146 MHZ ± X.XX. The 144 and 146 indicate the tuning range
being calibrated followed by either a plus or minus sign and the offset in KHz.
Enter the offset data as follows:
1. Tune the K3 to any frequency within the two meter band segment to be calibrated (144-145.999 or 146-
148 MHz).
2. Hold C O N F I G (hold function of the MENU switch) to access the CONFIG menu. Select XV1 ADR
and ensure Int Trn0 is selected.
3. With the VFO B knob, select XV1 OFS. The display will show either 144 x.xx or 146 x.xx, indicating
the range being calibrated. Use the VFO A knob to enter the frequency correction in KHz. Be sure the
minus sign is visible for a negative value. No sign before the offset number indicates a positive value.
If you have a signal generator or frequency counter you feel has the accuracy required, you can use it to refine
the calibration further by noting the difference between the generator or counter frequency display and the K3’s
display, then enter the difference as the offset value. Be sure you allow at least a 10 minute warm-up period. The
menu allows setting the desired offset within 10 Hz.
Status Light
The LED status light on the K144XV module provides operational and diagnostic information. If you suspect a
problem with the unit, remove the K3’s top cover to see the LED. (There is no need to do this during normal
operation.) The LED provides the following indications:
One or two flashes on Power
Up Passed Power On self test.
Note: The LED also flashes once briefly when you change
bands to or from 2 meters, or when you tune the VFO across
the 146-MHz boundary.
Remains on Continuously at
power-up
Power On self-test failed. This is usually due to a checksum
failure. Connect the K144XV to a PC running K144XV
Utility and Download/install the firmware (See Firmware
Updateson page 20).
Remains on Continuously
during normal operation Maximum heat sink temperature may have been exceeded
(60 C). Turn the K3 off and allow the K144XV to cool down,
then turn it back on. You can also send the ‘T’ command to
check the temperature (see Serial Port Control on page 21).
Flashes Rapidly
Normal while new firmware is loading, indicating serial data
is being received. (See Firmware Updates on page 20).