[Elecraft] interfacing with K2

[Bill Coleman]

On May 14, 2006, at 9:56 AM, Slater Tubman wrote:
>> I hope I have this correctly addressed as I do not send much mail  
>> to reflectors.
>>
>> I have the following equipment:  Powerbook G4, Rigblaster Plus  
>> interface, K2 (SSB, Tuner, NB, KIO2,  etc., but no high power)
>>
>> Question(s)
>> -is anyone out there running a similar physical setup?

Sorta. I have a K2/100 w SSB, NB, KAT100 and I use a 12" Powerbook G4  
and a homebrew interface.

>> -Successfully?

Yes.

>> -what program(s) do you use for digital modes?

Cocoamodem! It rocks! Find it here: <http://homepage.mac.com/chen>

>> -is a Rigblaster necessary to run Mac programs?

You do have to have some sort of interface between the sound ports of  
the Mac and the K2.

>> -if it is, do you run a USB/serial adapter to the serial port on  
>> the Rigblaster as well as the line from the computer USB port to  
>> the KIO2 port on the K2 by the special cable required for that  
>> interface?

It isn't necessary, but may be desirable. I use CocoaPTT to trigger  
the rig, and this goes through the USB to a Keyspan serial adapter  
with a standard PC DB-9 connection. I have a simple interface between  
the DTR line of the serial adapter and the PTT for the K2. It's just  
a NPN transistor with a resistor in the base lead. Works great.

>>   In other words, do we need two control cables?

I haven't run into this with Cocoamodem, but with some PC software I  
use. My homebrew interface that plugs into the DB-9 serial port on  
the PC has an extra DB-9 connector for plugging in the K2 as well, so  
I can get the serial interface into the PC as well.

>> -how do you handle audio in and audio out?  What is your cabling  
>> setup for this?

I run a small diameter coax from the microphone jack to my adapter  
box. I use a two-conductor shielded cable for the headphone jack to  
the adapter box. The adapter has a couple of 25 ohm resistors that  
are used to load the audio output of the Mac.

My adapter box is pretty simple. It consists of a 600:600 ohm  
transformer for the Mac headphone to rig microphone input, and a  
1000:8 ohm transformer for the Mac microphone to rig headphone  
output. There's a couple of variable resistors in place so I can  
adjust the levels. I also have a stereo headphone jack coming off  
that I can listen to the K2 output, too.

>> Part of the confusion is likely due to my PC sitting here eagerly  
>> awaiting my capitulation and my return to Windoze to run ham radio  
>> digital programs.

I can use the same interface to hook up a Windoze laptop, too.

Bill Coleman, AA4LR, PP-ASEL        Mail: aa4lr at arrl.net
Quote: "Not within a thousand years will man ever fly!"
             -- Wilbur Wright, 1901