Elecraft K3 Owner's Manual - Manual (Page 23)

23
Receiver Setup
This section explains how to use basic receiver
controls. Setup for specific operating modes is
described in later sections; see Voice Modes (pg.
28), CW Mode (pg. 30), and Data Modes (pg. 31).
Also see Text Decode and Display (pg. 33) and
Audio Effects (pg. 35).
Receiver Gain Controls
Use AF — SUB (pg. 11) to set the desired main
and sub receiver volume level. There are two
overall audio volume ranges, LO and HI, which can
be selected using CONFIG:AF GAIN.
Usually, both RF — SUB controls will be set
fully clockwise (main and sub receiver RF gain).
You may wish to reduce RF gain to optimize
receiver response to high signal levels or noise.
If the sub RF gain knob has been reconfigured
as squelch for both receivers, then the main RF gain
knob will control RF gain for both receivers. (See
CONFIG:SQ MAIN.)
To improve weak-signal reception, turn on the
preamp using
P R E . In the presence of extremely
strong signals, you may wish to use the attenuator
(
A T T ), or reduce the RF GAIN setting.
Crystal Filter Selection
You can install as many as five crystal roofing
filters in the K3’s main receiver, and another five in
the sub receiver. For diversity receive, matched
main/sub receiver crystal filters should be used (pg.
38).
Bandwidths as narrow as 200 Hz and variable-
bandwidth filters are available, thanks to the K3’s
low first I.F. (intermediate frequency) of 8.215
MHz. See Appendix A for recommended crystal
filter bandwidths for each mode.
To select a crystal filter manually, tap X F IL . The
FL1 - FL5 icons show the current selection. This
sets the DSP passband to match the crystal filter,
and removes any passband shift or lowcut/hicut.
The K3 will also select the most appropriate crystal
filters automatically as you adjust the
S H IF T ,
WID T H , L O C U T , and H I C U T controls.
Filter Passband Controls
As you rotate the filter controls (shift, width, hicut,
locut), the associated parameter value is shown on
VFO B. The filter graphic shows the width and
location of the passband, as illustrated below. In
these specific examples, segments that turned off as
a result of control movement are shown in gray.
High Cut
Low Cut
Width
Shift
Filter passband controls don’t apply in FM
mode. SHIFT control granularity can be set to
either 10 or 50 Hz in CW and DATA modes; see
CONFIG:PB CTRL. In Sync AM mode (
AM- S ),
SHIFT selects the upper or lower sideband.
Each passband control has an integral switch. These
switches are used as follows:
Tapping the control alternates between the two
primary functions for that control, for example
HICUT and WIDTH. This is indicated by the
two LEDs above each control.
Holding a control activates its secondary
function, labeled below the control.
Tapping or rotating a control shows the present
setting. To see the settings of both knob functions
without changing them, just tap the control twice.
The secondary functions of the controls are N O R M
and I/I I , described in the following sections.