[Elecraft] Digital Mode Interface for the KX3 for WSJT modes

[Lance Collister, W7GJ]

Hi Don,

The advantage of using the RTS line to trigger the PTT is that some software - 
notably WSJT - provides a high signal on the RTS line well in advance of the start of 
any audio tones.  This allows those of use who are using amplifiers, preamplifiers 
and coaxial relays to avoid "hot switching".  I know most KX3 users are QRPers and 
will be using the KX3 barefoot.  However, those of us who plan to use the KX3 with kw 
amplifiers do need to be careful not to hot switch things, and having a separate and 
real way to turn on the PTT in advance is very attractive.  Although I am extremely 
pressed for space and weight in my portable setup, I definitely will be rigging up 
something to provide RTS keying, rather than "VOX keying" for digital modes.

As soon as I receive my KX3 and get a chance to start building up a custom interface 
system so the KX3 can be used successfully on WSJT modes, I will share my results.

VY 73, Lance


On 7/13/2012 2:12 PM, Don Wilhelm wrote:
> Bill,
>
> You may want to re-think using the serial port on your interface.
>
> Most data mode applications like to use the same COM port for rig
> control (OK, maybe just frequency display) as they use to activate DTR
> or RTS for PTT.
>
> Given that the KX3 supplied cables only have RXD and TXD signals, using
> the serial port to generate PTT requires that either you use 2 serial
> ports (one may be the KX3 USB cable and the other can be a real port or
> USB to Serial adapter), or provide a "Y" adapter to go to your
> interface.  Use of the "Y" adapter precludes the use of the KX3 USB cable.
>
> There is nothing wrong with generating PTT from the audio stream, or
> just using VOX in the KX3.
>
> 73,
> Don W3FPR
> On 7/13/2012 9:51 AM, Bill Conkling wrote:
>> I am working on an interface in a box w/pcb.  Once you use a box, you can do
>> anything.  I plan to have full serial port and two audio cables from
>> computer.  Transformers in the audio chain and a 10K/1k attenuator in mic
>> input to KX3.  I will split the serial port to provide proper connections
>> for CAT, PTT, and CW as n1mm handles the K3.
>>
>> Whole thing in a 2.5X2.5X1 box.
>>
>> Big plans....
>>
>> ...bill nr4c
>>
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-- 
Lance Collister, W7GJ
(ex WA3GPL, WA1JXN, WA1JXN/C6A, ZF2OC/ZF8, E51SIX, 3D2LR, 5W0GJ)
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