Specifications

22
Special VFO B Displays
The KX3 can continuously display time of day or
one of several operational parameters on the VFO B
display. To access these displays, tap DISP , then
rotate the OFS/VFO B control.
The available special displays are listed below.
! 24-hour time obtained from the real-time-clock
on the KXBC3 option module. If a KXBC3 is
not installed, the time since last power-on will
be displayed. To set the time, use the TIME
menu entry. You can also set an alarm time
anytime in the next 24 hours using the ALARM
menu function. This may be useful as a
reminder of a contest or operating schedule.
The alarm will turn the KX3 on if it occurs
when power is off.
! Power supply voltage. This and the next four
parameters stay visible even in transmit mode,
so you can check key-down conditions.
! Internal battery voltage. An asterisk (*) is
added to this display during battery charging.
See BAT CHG menu entry.
! Supply current. Typical receive-mode current
is 0.15-0.2 amps (150-200 mA). It will be
higher with the backlight, preamp, or isolation
amp on, or when using the internal speaker.
Transmit current is typically 1 to 3 A, varying
with band, supply voltage, and load SWR.
! Power amplifier (PA) temperature. The PA
temperature will rise gradually as you transmit.
The KX3 reduces power if the PA is too hot.
! Synthesizer (OSC) temperature. Used by the
KX3 to adjust the synthesizer (or oscillator)
frequency as temperature varies. If the ambient
temperature is very low, it can take several
seconds for the reading to stabilize, during
which some drift in the oscillator frequency
may be observed. A few degrees of additional
temperature rise is also normal during transmit.
! Audio Signal level (AFV). This display shows
the approximate level of the KX3’s audio
output, prior to the AF gain control (in other
words, the AF gain control has no effect on the
reading). The reading will vary with preamp
and attenuator settings as well as the RF gain
control. AFV is normally used in conjunction
with the dBV function (at right).
! Relative audio signal (dBV). This display can
be used to measure receiver sensitivity or
gain/loss of various stages, or compare two
signals. To use it, first select AFV (described at
left) and allow the voltage reading to stabilize.
(This may not be possible with modulated or
rapidly changing signals.) Once the signal
appears stable, select dBV. You should now see
a reading of around 0 dBV (see Glossary)
relative to the last AFV reading. If you change
the setting of the preamp or attenuator, you
should see this reading change. However, it
may not change as much as you expect unless
you turn AGC off using the AGC menu entry.
(Be sure to turn AF gain down before
turning AGC off, as the signal may become
very loud.) Measurement of receive sensitivity
(MDS) requires a calibrated 1-µV signal source
such as an Elecraft XG3. These sources include
instructions for measuring MDS.
Extended Single Sideband (ESSB)
An increase in SSB voice bandwidth may improve
fidelity and reduce listening fatigue. However, this
also increases signal bandwidth, and is not
appropriate for use when bands are crowded.
ESSB receive
The KX3’s normal SSB receive bandwidth is about
2.8 kHz. This can be widened by using the PBT
control. In voice modes, by default function I is
low-cut and function II is high cut. Tap the control
to select function I or II, and rotate it to adjust the
passband. (Also see PBT SSB.)
ESSB transmit is set up as follows:
! Locate the TX ESSB menu entry. Tap 1 to turn
ESSB on, then use VFO A to select the desired
transmit bandwidth. The + icon will turn on in
the mode area of the LCD.
! ESSB, AM, and FM have separate TX EQ from
regular SSB, allowing you to optimize the
transmit passband for these wider-bandwidth
modes. See the TX EQ menu entry for details.
! You may wish to assign the TX ESSB menu
entry to a programmable function switch if
you’ll be turning it on/off frequently.