[Elecraft] K3 Operating Tip: Setting up for PSK and other digital modes

[Greg]

Setting up your K3 for PSK (and other audio-based digital modes)

The K3 is an outstanding platform for operating digital modes.  It already
has dedicated direct FSK and PSK with your CW paddles.  But there is also an
option to use Data-A mode to operate PSK or any other audio based digital
mode in conjunction with soundcard-based digital mode software.

It is usually best to use a second soundcard for your audio-base digital
modes.  This way you will not be plagued with Windows sound effects in your
waterfall or in your transmitted signal.  If you do not have that option,
you can always go into your Windows control panel and open “Sounds and Audio
devices.”  Select the Sounds tab and set Sound Scheme to No Sounds.

Here are the steps to setup for PSK using Data-A mode:

1.  Set your soundcard volume to about 50%.

2.  Connect soundcard output to the K3 LINE-IN.

3.  Connect the soundcard input to the K3 LINE-OUT.

4.  Set Menu item MIC SEL to LINE IN.  The K3 will remember this MIC SEL
source next time you use digital modes.

5.  Set mode to DATA. HOLD DATA MD to choose Data-A using the VFO B knob.

6.  Set power to ~20W (just something to start with).

7.  Use the MIC control to set the drive level so that your output is equal
or just below what you dialed in (20W in this case). Compression is locked
at zero automatically when in Data mode and cannot be adjusted.  You should
not see any ALC bars on the K3 display (when set to CMP/ALC).  When setup
this way I get excellent PSK31 results with TX IMD at ~ -26 dB to -32 dB - a
very clean signal.

FOR PTT

You can use a separate line for PTT from a computer COM port to the ACCY
connector or the RCA PTT connection on the back of the K3.  This requires a
simple circuit using a transistor and resistor between the COM port and the
K3.  You can find this circuit on many ham radio websites, including the
AA5AU RTTY website (this will be a hyperlink to
http://www.aa5au.com/rttyinterface.html ).  You can also use the RS-232
serial connection if your software allows you to set it up that way.  Not
all software allows you to do this.  Some programs will also allow PTT via
CAT command.

In the K3 CONFIG menu, set PTT-Key to either RTS - OFF or DTR - OFF. Then in
your software set PTT to either DTR or RTS as appropriate to the same COM
port the radio is connected to.



------------
73,
Greg - AB7R
Whidbey Island WA