31
Data Modes
You don’t need a computer to get started with data
modes on the K3: it can decode and display RTTY
and PSK31 on its LCD (pg. 33). You can transmit
in data modes using your keyer paddle (see CW-to-
DATA, pg. 34).
Using a computer for data modes is also very
convenient on the K3, as described below. If you’re
using AMTOR or PacTOR, also see pg. 32.
Data Mode Connections
You can transmit and receive data with a computer
in three ways:
Connect your soundcard I/O to the K3. Use
MAIN:MIC SEL to use LINE IN/OUT, front-
panel mic jack, or rear-panel mic jack. You can
use VOX or PTT to controltransmit.
Use the soundcard in receive mode, but use a
PC I/O line to do direct FSK (or PSK)
modulation. Connect the PC’s I/O line to the
“FSK IN” line on the K3’s ACC connector. (If
this signal originates from an RS232 port, it
will require RS232-to-TTL level conversion.)
Send and receive ASCII text via the RS232
interface. To send, insert text into a “KY”
command (e.g., “KY CQ DE N6KR;”). To
receive, send “TT1;” (text-to-terminal). “TT0;”
turns it off. See the K3 Programmer’s
Reference, available at www.elecraft.com.
Data Mode Selection
Soundcard-based data communications can be done
using LSB or USB mode. However, DATA modes
offer several benefitsnot available in SSB modes.
If you prefer to use LSB or USB, you’ll need to
manually set CMP to 0 to prevent data signal
distortion. Refer to your data communications
software manual to determine how to set up the
VFO and computer for accurate frequency display.
To use DATA modes, tap MOD E until the DATA
icon appears. Next, holdDAT A MD. The present
data mode is shown on VFO B, and can be changed
by rotating the VFO B knob.
The following data modes are available:
DA TA A can be used for all Audio-shift
transmit modes, including PSK31, MFSK,
AFSK, etc. The VFO displays the suppressed-
carrier frequency, just as when SSB modes are
used for data. USB is “normal” for DATA A.
Compression is automatically set to 0.
AFSK A also uses Audio-shift transmit, but is
optimized for RTTY. The VFO displays the
RTTY mark frequency, and LSB is “normal”.
The built-in text decoder can be used in this
mode (pg. 33), as well as the dual-tone RTTY
filter (DTF, pg. 32).
FSK D is identical to AFSK A, except that
Direct modulation is used, via FSK IN, ASCII,
or the keyer paddle (pg. 34). The text decoder
can be used in this mode (pg. 33), as well as the
dual-tone RTTY filter (DTF, pg. 32).
PSK D is a Direct-transmit mode for PSK31.
It’s the only mode that decodes and displays
PSK31 signals with the text decoder (pg. 33).
Like FSK D, PSK D letsyoutransmit via
FSK IN, ASCII, or the keyer paddle (pg. 34).
You can also use auto-spot with PSK D if the
tuning aid is displayed (C W T , pg. 34).
The DAT A MD display also shows the data speed in
bps on VFO A. This is relevant only ifthe text
decoder is on. Depending on the mode, other data
speeds may be available; select them by rotating
VFO A.
Also shown is the current sideband (LSB or USB).
If this sideband is considered “data reverse” for the
present mode, then REV also appears. You can use
ALT to switch tothe other sideband if required.
Mark/Shift and Pitch Selection (PITCH)
Hold PITCH to view and change the received mark
tone and shift (AFSK/FSK) or center pitch (PSK).
In AFSK/FSK modes, you have a choice of mark
tone/shift combinations. Use VFO A to select a
tone/shift combination that’s compatible with your
software. A lower mark pitch makes signal tuning
easier when using the K3’s text decoder.
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