Elecraft KX3 Owner's Manual - Manual (Page 12)

12
Receive Settings
The RX control group, shown below, is used to set
up the KX3’s receiver. Directly above these
controls is the filter passband graphic, which shows
the shape and position of the receiver’s passband.
This determines what pitch range you’ll hear.
AF Gain, RF Gain, and Squelch
The
A F / R F - S Q L
knob normally controls
receiver AF gain. Tapping the knob switches its
function to squelch (FM mode only) or RF gain
(all other modes). Also see “AF, RF, and IF” in the
glossary (pg. 52).
RF gain is normally left at maximum ( -0 d B ).
Reducing RF gain may be useful in some strong-
signal conditions. If you reduce RF gain more than
a few dB, a separate segment of the S-meter turns
on as a reminder. The segment used varies with the
amount of RF gain reduction. (A high S-meter
reading may hide the RF gain indicator segment.)
Squelch is used to mute the receiver until a signal
appears. It is most often used with repeaters. The
control adjusts the signal threshold required for
squelch to “open,” unmuting the receiver.
Voice Monitor/CW Sidetone Level (MON)
Holding
A F / R F - S Q L
temporarily switches its
function to M O N , which controls how much of
your own signal you hear when transmitting.
Transmit monitor setup is covered on pg. 14.
Switch activation tones, if used, have the same
volume level as the CW sidetone (as set in CW
mode using
M O N ). Switch tones can be set to
off, on, or Morse code characters at various speeds
using the SW TONE menu entry.
Passband Tuning Functions (PBT I/II)
The
P B T I / I I
control is used to shape the KX3’s
receive filter passband. In general, a narrow
passband reduces interference (QRM) and noise
(QRN), while a wider passband improves fidelity.
In voice modes, tapping
P B T I / I I
normally
selects low-cut (function I) or high-cut (function
II). These functions remove low- or high-pitched
interfering signals. Examples of filter graphic
segments that might turn off as the result of a low-
cut or high-cut are shown in light gray below. (To
select width/shift for SSB, instead, use PBT SSB.)
Low-Cut High-Cut
I II
In CW and DATA modes, the passband functions
are width (I) and shift (II). The effect of these
functions is illustrated below. Reducing the width
or shifting the passband may attenuate an
interfering signal above or below the desired one.
Width Shift
I II
Holding
P B T I / I I
normalizes the passband
( N O R M ), centering it and setting it to the default
width for the current mode. Two small "anchors"
appear at the left and right ends of the graphic.
Holding NORM again restores the previous
passband settings.
Roofing Filters (XFIL)
The X FIL icons, to the right of the filter passband
graphic, show whether the optional roofing filters
(
FL2 , FL3 ) are in use. These filters, located on the
KXFL3 option module, can reject strong nearby
signals that might interfere with weaker ones.
When FL1 is indicated, the roofing filters are
bypassed, and the pre-DSP bandwidth is about 15
kHz.
FL2 (3000 Hz) and FL3 (1000 Hz) are
automatically selected, when possible, based on the
operating mode and settings of the filter controls.
Dual watch (MENU:DUAL RX) also uses FL1,
overriding the normal per-mode filter selection.