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KX3 - RMS Express USB Data Mode

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N4KDJ

KX3 - RMS Express USB Data Mode

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.

I checked with Elecraft and they felt good about my settings, Mic Bias On,
Mic Gain 12 (4 solid 5th ALC bar flickering). I used the USB Data selection
in RMS Express and that set the radio to DATA A. FL2 would show (I have the
roofing filters).

The poor performance continued, then by error I found that I had hit the
mode button and gone to USB not DATA A - it worked great! Later changed
back to DATA A and it was slow, hit Mode and it sped right up and the error
conditions largely eliminated. Transferred a 31K file in 3-4 minutes.

Back to a try with Winmor and the Navigator. With DATA A mode I gave up on
the 31K file after 17 minutes. Trying in regular USB it took 6.6 minutes -
about twice P3, more or less what I would expect.

So I am totally confused about DATA A mode - using both sound card (Winmor)
and TNC. I haven't had the opportunity to play with other digital modes as
yet, but wonder whether the DATA A mode is advisable. Am I missing
something?

Keith, N4KDJ

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g0hww

Re: KX3 - RMS Express USB Data Mode

Hi Keith,

I recently noticed something odd with my KX3. I thought that the RX EQ
feature was inhibited in DATA-A mode, but it seems that it cannot be
adjusted but is still applied. If I set the RX EQ in USB mode, I can
still see the adjusted response in DATA-A mode, but I cannot adjust it
in that mode. Perhaps this could be related to your issue, Keith? Is
this normal?

Also, it seems that in DATA-A mode, the audio drops off at about 400Hz
(with the PBT with of 4kHz centred on 1.5kHz), whereas in SSB mode, it
looks more like 200Hz. I wonder why this is? I would prefer more bottom
end in DATA-A mode, I think.

Cheers,

Darren, G0HWW

On 23/04/14 01:08, Keith D Jones wrote:
<snip>

>
> So I am totally confused about DATA A mode - using both sound card (Winmor)
> and TNC. I haven't had the opportunity to play with other digital modes as
> yet, but wonder whether the DATA A mode is advisable. Am I missing
> something?
>
>
>
> Keith, N4KDJ
>

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Don Wilhelm-4

Re: KX3 - RMS Express USB Data Mode

In reply to this post by N4KDJ

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.
>
>
>