[Elecraft] K3 PK-232 FSK RTTY Setup

[Ed Gray W0SD]

For those now or in the future wanting to setup the PK-232 with the K3
using FSK here is the information.  I would think you could do this very
similarly for the Hal and  other TNC'S.  Of course the specific wiring 
would be different but the same general hook up should work.  This set 
up does not use the computer sound card at all.

First you need a software program to control the PK-232 or the TNC you
are going to use.  I used Writelog but there are other software programs
that will work.

The PK-232 has a cable from it to a serial COM port port on your 
computer which you need to set up in your software, in my case Writelog. 
That is all you need between the PK-232 and the computer.  There is 
absolutely nothing hooked to the computer sound card.

The K3 should be set to FSK D, see page 31 of the K3 manual revision D1.
Next you should be sure your software program is set up for the same
tone and shift that you have the K3 set to.  On the K3 activate pitch
and set it accordingly.  Most common would be 2125-170 which is what I
have Writelog set at.

 From the K3 run an audio line from the line out to the Radio 1 or Radio
2 RX input on the PK-232.  This jack is hooked respectively to the same 
place as J4 or J6  which is the 5 pin flat connector.  I would suggest 
using Radio 1 and running an audio cable from the K3 line out to J3 
which is the Radio 1 RX input.  The K3 end is a sterio plug and the 
PK-232 is a mono plug. On the K3  go ahead and use a stereo cable and 
plug it into the K3 line out.  On the PK-232 end of this cable cut off 
the stereo plug and solder on a mono plug.  The tip from the stereo plug 
should be hooked to the tip of the mono plug which will be the left 
channel.  This will be the K3 audio.  The ring(one next to the tip) 
would be the SUB so just leave it unhooked and hook the barrel from the 
stereo plug to  the ground of the mono plug.  Go to the K3 config:Line 
out.  I set it for about about 25.  Remember the K3 manual is talking 
about sound card input when they mention 10 and here we are talking 
about input into the PK-232. The PK-232 manual says to have at least 200 
mv RMS of receive audio. Using my scope and then calculating RMS I came 
up with the setting of 25 to get 200 mv RMS.  It is better to be a 
little low than too high so you don't have distortion.

For FSK transmit you need to hook the PK-232 FSK keying which is pin 1
of the DIN plug J7 to Pin 1 FSK Input of the K3 accessory plug.  You
hook the ground, Pin 2 of J7 to Pin 5 of the K3 accessory plug. J7 on
the back of the PK-232 is labeled so that is easy.  The K3 accessory 
jack information is on page 18 of the K3 manual revision D1.

Be sure and note that the picture you are looking at in the K3 manual of
the accessory jack is the radio pin out and not the plug on the cable
you are making so be careful to use the correct pins. I just took a
Video cable and cut the female connector off and used the appropriate
wires to hook to the PK-232. The extra wires can be folded back and cut
to different lengths and heat shrink tubing put over them so no wires
can short to each other.

 From J4 on the PK-232 which is the 5 pin flat connector hook up the PTT
line Pin 5 to the K3 accessory plug pin 4.  This should complete the FSK 
setup for the K3 with the PK-232.

Ed W0SD