[Elecraft] [K3] Need help with soundcard digital mode transmit (retry)

[David Herring]

Sorry, let me clarify my response.

The K3's VOX does respond to Line-In in my experience.  No separate PTT is needed.  Also, for the K3, no voltage reduction is needed if you are using the Line-In jacks.  I have not tried using the microphone input for digital as I keep that for, oddly enough, my microphone. ;-)

I homebrewed my audio cables out of twisted-pair cat5 ethernet cable, and even with the antenna occasionally in the room, no ill-effects from RF have been noted.

HTH,

Dave, AH6TD


On Jun 9, 2011, at 10:47 AM, Peter Wollan wrote:

> Don,
> 
> Ok, I looked at the reference I gave, and the information I thought
> was there isn't.  But it's not quite what you want, anyway.  There are
> three separate parts:  the Mac, the K3, and the connection between.
> The Mac is easy:  you want to use either CocoaModem or FLDIGI, and
> they are both excellent.  For the K3, you need to look in the manual.
> You need three signals:  sound to the Mac, sound from the Mac, and
> PTT.  It sounds like it's going to be easier with the K3 than with the
> K2, in that the K3 apparently can accept line-in input -- the K2
> needed to have the Mac sound signal brought down to microphone levels.
> Can the K3 respond to line-in as input to Vox?  If yes, that's your
> PTT.  If not, you need to either reduce the voltage, like with the K2,
> and plug it in as if it's a microphone, or give up on Vox and generate
> a PTT signal.  If you do that, you need a somewhat fancier interface,
> like the Signalink box.
> 
> So, I guess I haven't been as helpful as I thought I could be.  It
> might be as easy as using two stereo cables, one for sound in and one
> for sound out, but it depends on the capabilities of the K3.
> 
>      Peter W0LLN
> 
> 
> On Thu, Jun 9, 2011 at 12:34 PM, Peter Wollan <peter.wollan at gmail.com> wrote:
>> Don,
>> 
>> The CocoaModem web site has some information about connecting, as well
>> as configuring the software to successfully transmit.  I've used both
>> CocoaModem and Fldigi, but the connection process is the same:  from
>> the K2 to the Mac is a simple stereo cable, headphone socket to
>> headphone socket.  From the Mac to the K2 requires a stereo cable to
>> 8-pin microphone plug, with a couple of resisters as a voltage
>> divider, soldered in the plug, to convert the line-out voltage level
>> to mic level.  I think the K3 is the same.
>> 
>> Then, the levels have to be set right at both ends, the radio and the
>> laptop, to have Vox trigger properly.  Basically, you want to turn it
>> up high enough to trigger without being too high and having
>> distortion.
>> 
>> CocoaModem:  homepage.mac.com/chen/w7ay/cocoaModem/index.html, look
>> under "interfacing".
>> 
>>     Peter W0LLN
>> 
>> 
>> 
>> On Thu, Jun 9, 2011 at 12:03 PM, Don Putnick <don.putnick at earthlink.net> wrote:
>>> Hi all,
>>> 
>>> I'm the proud new papa of Elecraft K3 #5495. I've been able to receive PSK31 via both the rear line-out and the rear speaker jacks. The line-out jack appears to be at a fixed level, which is a little low, but the rear speaker jack with volume control works just fine (that's the approach I used on my Yaesu FT-890).
>>> 
>>> The problem is I can't get my MacBook to work with the VOX. I've tried the rear line-in and the rear mic jacks, VOX Gain and LOW/HI MIC gain, all in DATA A. Haven't tried USB mode though. And yes, the MacBook is putting out a PSK31 signal.
>>> 
>>> I'd really appreciate any helpful hints.
>>> Thanks and 73, Don NA6Z
>>> 
>>> 
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