[Elecraft] Running DM780 with the K3

[Sam Morgan]

Since this has come up twice lately I will risk sharing my notes.
Please take them with a grain of salt and not as gospel.
Different sound cards, etc, may cause different results.
YMMV

I did all this many months ago,
after I got it running I never got back on the air with it,
just not as much fun as a key, imo.


++++++++++++++++++++++++++++++++++++++++
Note use instructions below xxxxxxx
for SignaLink USB DM780 and Data A mode on K3
-------------------
For use with SignaLink USB DM780 and mode (USB)

DM 780
Soundcard
input: USB Audio CODEC
       Source: blank
output: USB Audio CODEC
        Source: Wave

TX Gain needs at least 75% on both volume and wave
RX gain shows just before 3 bars
PTT: None (via soundcard PTT or radio VOX
---
Elecraft
MENU: MIC SEL FP.L
CONFIG: Line Out = 10

Mic gain = 23-34
Compression = 0
---

Signal link
Using SignaLink Cable #SLCAB8R
(SignaLink USB mic jack into front mic jack)
SignaLink SPKR (mono wire) to K3 Line Out (stereo) Jack
(also has stereo line to computer in same jack)

TX = 25%
RX = barely cracked open
Delay = ~20%

xxxxxxxxxxxx
using SignaLink USB with DM 780 and K3 in Data-A mode

DM 780
Soundcard
input: USB Audio CODEC
       Source: blank
output: USB Audio CODEC
        Source: Wave

TX Gain needs at 100% on both volume and wave
RX gain shows just before 3 bars
PTT: None (via soundcard PTT or radio VOX)
---
Elecraft
MENU: MIC SEL LINE IN
CONFIG: Line Out = 10

Mic gain = 25
Compression = 0
---
Signal link
Using SignaLink Cable #SLCABK3

TX = 50%
RX = barely cracked open
Delay = ~20%

http://www.elecraft.com/K3/k3_operating_tips.htm#psk%20audio
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 see 4 bars of ALC and
output is equal to, 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.  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.  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.
++++++++++++++++++++++++

hope there may be something in there that will help.
if not feel free to use exercise your delete key!

--
GB & 73
K5OAI
Sam Morgan

On 12/31/2010 2:36 PM, Don Wilhelm wrote:
> Mark,
>
> Please explain what you mean by "waterfall display is super messed up" - the
> K3 defaults to a 400 Hz width for DATA A and that would show a narrow band on
> the waterfall until you increase the width.  BTW, DATA A is the only one you
> should use, the other data modes are for RTTY or PSK generated by the CW
> paddles (and may generate very strange waterfall displays).
>
> Note also, that if you select the operating band/frequency and mode by
> clicking in DM780/HRD, you may end up in USB mode instead of DATA mode - I
> use the K3 tuning for that reason.  Maybe Simon will fix that someday.
>
> For transmit, make certain you have set the Line-in level so that you obtain
> 4 bars on the ALC display with the 5th bar flickering, then set the power
> with the K3 power control, ignoring the advice in many interface boxes to set
> the power level by controlling the audio level - that will not work right
> with the K3 (nor with the K2).
>
> I believe it is Signalink that normally provides microphone level audio to
> the transceiver, but there is a jumper inside to increase it to line level.
> To drive the K3 Line-in, you must change the jumper in the Signalink.
>
> 73, Don W3FPR
>
> On 12/31/2010 2:23 PM, pastormg2 at verizon.net wrote:
>> I am currently using a signalink USB with HRD and DM780.  I have DM780
>> keying the K3 which is set for PTT vs VOX.  I am trying to transmit PSK31
>> and the mode set on the K3 is USB vs Data. Not sure if that is correct or
>> not but when I choose the mode Data the waterfall display is super messed
>> up. But when the mode is set to USB it looks perfectly normal.
>>
>> But, when I hit the transmit button the K3 goes into transmit mode but it
>> looks as if no power is being registered on the meters even though I have
>> the transmit power set at 40 watts.  Am I doing something wrong?  Any help
>> would be appreciated.  Mark KB3Z