BFO Alignment
If the BFO frequencies are shifted too high or too low, it may be
due to one of the following:
The K2 uses a variable-bandwidth crystal filter, allowing the
If you didn't calibrate the K2's internal frequency counter
using
operator to set up as many as four filter bandwidths for each
operating mode. Each of these filter configurations requires an
an external counter, it may not be reading accurately. If
appropriate BFO setting, which determines the pitch you hear.
possible, borrow an accurate counter and re-do the
4 MHz
Filter and BFO set up is done with the
CAL FIL
calibration
Oscillator Calibration
.
function.
CAL FIL
is described in detail in the Operation
section
The BFO range shift could be due to the inductance of L33
of the manual, under Calibration Functions. Rather than
duplicate
being too high or too low. However, since L33 is supplied
prewound
this information here, the instructions and example in the
and tested, this is unlikely.
Operation section will be used.
The leads of R116 may have been heated excessively
during
Make sure the bottom cover is securely attached.
soldering, shorting out a portion of L33's turns.
Tap
PRE/ATT
until the
PRE
annunciator is turned on.
(Turning the preamp on will provide some background noise so
you
One of L33's leads could be broken. Look closely at the
leads
can hear the effect of changing filter bandwidths.)
using a magnifying glass.
Follow all instructions on page 85 to become familiar with the
One or more of the capacitors or varactor diodes in the BFO
CAL FIL
function.
circuit could be of the wrong value.
Perform the steps in the example on page 86 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.
4
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