[Elecraft] DATA A mode and WSJT-X

[Rick Bates]

Be sure to keep your audio input (RX) as low as you can.  Your pic could be a result of high audio levels. 

On my K3, I set LIN OUT at 1, then set the driver level just high enough to allow decoding (3/100 in the Windows driver).  Overdriving causes myriad issues, mostly causing the decoding to fail or work poorly and it will FUBAR the waterfall.  You do NOT want to tickle the sound card AGC, ever, if you want to watch multiple conversations. That's difficult to manage. 

If one signal is substantially blocking the signal you want (hitting the AGC, lowering the apparent level to other Q's), adjust the Hi/Lo cut (and center freq) to filter it out.  This is effective in any digital mode.  A P3 or a good waterfall display helps in this. 

Any sound device 'feature' should be disabled (shaping, boost, bandpass etc.).  Otherwise it only mucks with the decoder.  The K(X)3 in Data A mode gives flat audio; exactly what the decoder wants to see; allowing it the best chance of performing well. 

73,
Rick wa6nhc

Tiny iPhone 5 keypad, typos are inevitable

> On Jan 23, 2015, at 9:54 PM, Edouard Lafargue <edouard at lafargue.name> wrote:
> 
>  Oh yes, I kind of forgot the most obvious :) It is KX3, running on a beta
> firmware (2.33, not sure it is released yet).
> 
>  The only difference between the two sections of the screenshot are USB
> and DATA A mode, nothing else changed. Very strange. The "Flatten" checkbox
> is checked, I will try with the checkbox unchecked tomorrow morning and
> report.
> 
>  On other programs like fldigi, the only difference between USB and DATA A
> (both with widest possible filter bandwidth) is a cutoff at 500Hz on DATA A
> whereas USB goes a bit lower.
> 
>  Thanks for all your feedback so far!
> 
> Ed W6ELA
> 
>> On Fri, Jan 23, 2015 at 9:50 PM, Matt Zilmer <mzilmer at roadrunner.com> wrote:
>> 
>> Yep, there is always a first time for any mode.  I remember when PSK31
>> was introduced and I tried it.  Had a problem similar to yours, but on
>> a FT101EE at that time.
>> 
>> I've used JT65 on my K3 many times, with DATA A as the mode.  I can
>> assure you that it works fine.  But that is here, and with a different
>> configuration (well, probably).
>> 
>> The spectrum you posted was a surprise.  You should be seeing tones
>> between 1270 and 1953 Hz, and they would show as discrete "blips". The
>> spectrum shown is not at all like that.
>> 
>> I'd be scratching my head too, Ed.  It may be something simple, and
>> probably is.  I'll think about it a bit though.  Maybe others will
>> consider this as well.  It's a little perplexing.
>> 
>> Which Elecraft transceiver are you using?  Both the K3 and KX3 support
>> DATA A modes.
>> 
>> 73,
>> matt
>> W6NIA
>> 
>>> On Fri, 23 Jan 2015 20:51:23 -0800, you wrote:
>>> 
>>> I tried JT65 for the first time today (there is a first for everything,
>>> right?), and to my surprise, I discovered that for some reason, the DATA
>>> mode is not usable on that program!
>>> 
>>> Not 100% sure the mailing-list allows images in emails, so I will try to
>>> describe the issue as clearly as possible:
>>> 
>>>   - In USB mode, with a flat EQ, I get a flat spectrum apart from the
>>> actual JT9/JT65 chirps, from 200Hz to 3000 Hz
>>>   - In DATA A mode, on the other hand, I get a peak around 100Hz,
>> nothing
>>> until 300Hz, then a huge noise peak raising from 300Hz, peaking at 500hz
>>> and going slowly down to 1kHz. Then a big dip in signal/noise centered
>>> around 2kHz. In other words, very distorted signal!
>>> 
>>>    Image speaks for itself: http://imgur.com/QyqpzEh
>>> 
>>>     I am pretty sure this does not come from the radio, with a simple
>>> audio waterfall displaying at the same time in another program I don't see
>>> this artifact, but I wonder if anyone else has seen this and can explain
>>> it? Could it be an FFT artifact linked to the sampling rate of the
>>> soundcard and an internal sampling rate of the radio in DATA mode?
>>> Something else ??
>>> 
>>>   Kind of scratching my head on this one, maybe smarter/more experience
>>> Hams on the list will have an answer!
>>> 
>>>  Oh yes: WSJT-X is running on a Mac, not that it should really matter.
>>> 
>>> 73 de Ed, W6ELA
>>> ______________________________________________________________
>>> Elecraft mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>>> Help: http://mailman.qth.net/mmfaq.htm
>>> Post: mailto:Elecraft at mailman.qth.net
>>> 
>>> This list hosted by: http://www.qsl.net
>>> Please help support this email list: http://www.qsl.net/donate.html
>>> Message delivered to mzilmer at roadrunner.com
>> Matt Zilmer, W6NIA
>> --
>> "Give me six hours to chop down a tree and I will
>> spend the first four sharpening the axe." -A. Lincoln
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to happymoosephoto at gmail.com