Elecraft KX3 Owner's Manual - Manual (Page 13)

13
Preamp and Attenuator
P R E turns on the RF preamp. It should be used
only when signals are very weak. Preamp gain can
be set on a per-band basis using MENU:PREAMP.
A T T N turns on the 15-dB RF attenuator, which can
protect the receiver from strong interfering signals.
The KX3 will automatically reduce receive gain
in the presence of very strong signals. The receive
overload icon (
R X ) will alert you to this (pg. 8).
Noise Reduction
Noise reduction (NR) removes random background
noise (hiss or static). It has a characteristic “hollow”
sound. Higher settings may attenuate weak signals.
Holding N R turns on noise reduction and displays
its setting, which can be adjusted using the knob
above the switch. Tap any switch to exit the setting
display. Hold
N R again to turn noise reduction off.
Noise Blanking
Noise blanking can eliminate repetitive noise such
as that from power lines, appliances, and vehicle
ignitions systems. Use the lowest effective setting
to avoid unwanted signal/noise interaction.
N B turns on the noise blanker. The NB setting is
adjusted in the same way as NR (see above).
Audio Peaking Filter (APF)
A P F turns on a very narrow filter that improves
copy of very weak CW signals buried in noise. The
filter graphic changes to that shown below. With
APF on, PBT function I still adjusts the overall
passband width; function II tunes the APF center
pitch. 1-Hz VFO tuning is automatically selected.
Notch Filtering
In CW and data modes, holding N T C H turns on a
manually adjusted notch filter and displays the
notch pitch. Adjust the pitch, using the knob above
the switch, until an interfering carrier is reduced in
volume. Tap any switch to exit the notch pitch
display. Hold
N T C H again to turn it off.
In SSB and AM modes, N T C H turns on auto-notch,
which locates and suppresses one or more carriers
automatically.
CW/DATA Tuning Aid (CWT)
Accurate tuning of received signals is required
before you call a station, or when you’re using
built-in text decode (
T E X T , pg. 16). Tuning can be
done by ear. But CWT, in conjunction with Auto-
SPOT (below), can often tune in stations for you.
When you hold
C W T , the upper half of the S-meter
becomes a receive VFO tuning aid for CW and
some data modes.
A CW signal will appear as a single bar in the CWT
display, as shown in the left example below. Use
VFO A to tune in the signal until the bar directly
under the CWT pointer is turned on. A narrow filter
width is recommended (100-400 Hz). This display
also applies to PSK31 (PSK D, pg. 18).
CW and PSK31 RTTY
In RTTY or radioteletype modes (FSK D, AFSK A;
pg. 18) mark and space tones are represented by
three bars on either side of the CWT pointer. If no
RTTY signal is present, you’ll see the “ghosting”
effect shown above. As you tune in an RTTY
signal, the number of solid bars will increase. Keep
tuning until you see a rough balance between left
and right solid bars during an RTTY transmission.
SPOT and Auto-SPOT
You can use S P O T to manually tune in a CW or
PSK31 signal, matching it to your sidetone pitch.
First turn off
C W T if it is on. Then, tap S P O T and
adjust VFO A until the signal pitch matches the
sidetone. Use
M O N to adjust the sidetone
volume level.
To use auto-SPOT: First turn on C W T . Tapping
S P O T will then automatically tune in a received
signal that falls within the CWT display range.
If RIT is turned on, auto-SPOT will change
the RIT offset, not the VFO A frequency.
Auto-SPOT may not be usable if more than one
signal is in the CWT range, or if the signal is very
weak or noisy. Try using a narrower bandwidth in
this case.
50 100 2 3 SWR RF
CWT
S1 3 5 7 9
50 100 2 3 SWR RF
CWT
S1 3 5 7 9