[Elecraft] K3 & DM 780

[Jim Brown]

On 12/31/2010 1:27 PM, goldtr8 at charter.net wrote:
> I want to use DM 780 with my K3 to work either CW or one of the data
> modes.
>
> I can get the DM 780 to decode signals, but if I try to TX, I am unable
> to trigger the radio to do anything.

First, the K3 must be in the DATA A mode, and you need a cable from the 
output of the sound card to the line input of the K3, and the playback 
mixer in your computer must be set to send the .wav generated sound to 
the computer output.  Second, you need to get the K3 to transmit. One 
VERY easy way to do that is to use VOX.  That's what I do for both PSK 
and RTTY. You can also do it by command from DM780. Don't ask me how -- 
it's been a couple of years since I've run PSK.  Third, you have to 
place DM780 in transmit mode.  Study the doc for DM780 for answers to 
both questions.  Next, you need a serial connection between the computer 
and the radio. Use a real serial connection if your computer has one, or 
a USB to serial if you don't.

There's a lot of detail about the various connections and how to set 
levels in http://audiosystemsgroup.com/HamInterfacing.pdf   and in 
http://audiosystemsgroup.com/RFI-Ham.pdf   Both are free downloads.  It 
is VERY important to set levels correctly. If you don't, you can create 
a lot of interference to other PSK users.  It's easy to get right if you 
follow the instructions.

73, Jim Brown K9YC

73, Jim K9YC