Elecraft K2 Owner's Manual User Manual

Page 67

LECRAFT

BFO Alignment

The K2 uses a variable-bandwidth crystal filter, allowing the operator
to set up as many as four filter bandwidths for each operating mode.
Each of these filter configurations requires an appropriate BFO setting,
which determines the pitch you hear.

Filter and BFO set up is done with the CAL FIL calibration function.
CAL FIL

is described in detail in the Operation section of the

manual, under Calibration Functions. Rather than duplicate this
information here, we'll refer you to the instructions and example in the
Operation section.

Make sure the bottom cover is securely attached.

Tap

P R E / A T T

until the PRE annunciator is turned on. (Turning

the preamp on will provide some background noise so you can hear
the effect of changing filter bandwidths.)

Follow all instructions on page 91 to become familiar with the

CAL FIL

function.

Perform the steps in the example on page 93 to set up all filters.

You'll use the filter and BFO data from Table 8-1 (for a CW-only K2),
since the SSB adapter is not installed. If you later install the SSB
adapter, you can easily change the settings to take advantage of the
optimized, fixed-bandwidth SSB filter.

VFO Linearization

Make sure the bottom cover is securely attached.

Allow the K2 to stabilize for at least 10 minutes at room

temperature (approx. 20-25

C). (Note: Avoid using a high-wattage

work lamp direct above the K2 during calibration. With the top cover
removed, this could heat the RF board to a higher temperature than
would ever be seen during normal operation.)

Connect the internal frequency counter cable to the VCO output

test point (TP1).

Use the procedure listed below to linearize the VFO. If you see

any INFO messages, refer to Troubleshooting.

1. Use

B AN D +

B AN D -

to select 40 meters. Select CW normal

mode and filter FL1.

2. Set the VFO to anywhere in the range 7000-7100 kHz.
3. Enter the menu and select CAL PLL, then hold

E D I T

a second

time to start the VFO linearization sequence.

4. The frequency counter will show the VCO frequency as it

decreases through a range of about 10-13 kHz. (The letter "d" will
flash each time a calibration data point is stored.)

5. When calibration is completed (4-8 minutes), you'll see the

message End on the LCD. You can then tap any switch to return
to normal operation. If you see an INFO message rather than
E n d

, refer to Troubleshooting (Appendix E).