[Elecraft] KX3 - RMS Express USB Data Mode

Don Wilhelm w3fpr at embarqmail.com
Tue Apr 22 20:57:47 EDT 2014


Keith,

DATA A mode is exactly like SSB except that it automatically turns off 
compression and the TX EQ.
So I would suspect that your problems have more to do with your software 
application and the commands it sends to the K3 than anything else.  If 
your application is switching the KX3 to SSB mode rather than staying in 
DATA A submode,  the compression and TX EQ settings you have for SSB 
would distort the data mode signal.

Some software applications (older Ham Radio Deluxe and others) will 
switch the K3 and KX3 out of Data mode and into SSB mode.  I don't know 
what Winmor and Pactor 3 will do.
The solution that I have used is to not let the software change modes - 
in other words, do not click on spots or the data mode frequencies in 
the software, but look at the frequency and use the K3/KX3 VFO to move 
to those frequencies.

BTW, if you are using the microphone input from your interface, mic bias 
should be set to OFF.  If there are transformers in your interface box, 
the addition of mic bias can cause current to flow through those 
transformers and create distortion to the data stream.  If you want to 
leave Mic Bias turned on, add a series capacitor (1 uF to 2.2 uF) in 
series with the AF line to eliminate the DC current through the transformer.

73,
Don W3FPR

On 4/22/2014 8:08 PM, Keith D Jones wrote:
> I got my KX3 and KPA100 this past February and have a lot of fun so far with
> it.  I've been pretty frustrated the past few days trying to get
> satisfactory RMS Express performance using both Pactor 3 and Winmor.
>
>   
>
> I built a cable for my Navigator and quickly had it working with the KX3
> choosing the USB Data mode in the Radio Setup (K3 radio choice).  I quickly
> made a connection and sent a small message.
>
>   
>
> The past few days I have been trying to get my SCS PTCIIex Pactor 3 modem
> hooked up.  I built a cable and rebuilt it 2 more times!  The problem that I
> kept getting was a connection and either very slow and error (ARQ Repeat in
> RMSE and error light on TNC) or a disconnect after unsuccessful handshaking.
> Since I could connect I thought that maybe there was a problem with the
> cable.
>
>   
>



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