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K3S Shift Setting for WSJTX

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KQ5S-Tom

K3S Shift Setting for WSJTX

Hope this is not a dupe. I sent it over an hour ago and nothing showed up.

I am trying to tweak my WSJTX setup. What is the recommended shift for the
K3S while running WSJTX? I have the 2.8 khz SSB filter installed. I am
using a width of 4 khz and using the radio in split mode.

73,
Tom - KQ5S
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Joe Subich, W4TV-4

Re: K3S Shift Setting for WSJTX

> I am using a width of 4 khz and using the radio in split mode.
Width of 4 KHz is useless with a 2800 Hz SSB filter. You do not
need (and can't use) more than 3000 - 3300 Hz.

The default shift of 1500 (for DATA A) will provide relatively
flat audio response from 300 Hz to 2800 Hz with Width at 3000 Hz.
If you move the shift to 1700 the "flat area" of the audio pass-
band will be about 300 to 3000 Hz.

Remember, with a 2800 Hz filter the maximum bandwidth is 2800 Hz
between the -3 dB points. Setting a wider DSP filter is not going
to make the flat are any wider it will only allow you to see more
of the filter skirts. If you really need the full 4 KHz get an
AM (6 KHz) or FM (13 KHz) filter.

73,

... Joe, W4TV

On 7/2/2017 3:50 PM, Tom-KQ5S wrote:

> Hope this is not a dupe. I sent it over an hour ago and nothing showed up.
>
> I am trying to tweak my WSJTX setup. What is the recommended shift for the
> K3S while running WSJTX? I have the 2.8 khz SSB filter installed. I am
> using a width of 4 khz and using the radio in split mode.
>
>
> 73,
> Tom - KQ5S
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
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Bob McGraw - K4TAX

Re: K3S Shift Setting for WSJTX

In reply to this post by KQ5S-Tom

Why split? The K3S should be in Data A mode and should switch to Data
when you allow WSJT-X to connect. Typical bandwidth for receive is 2.4
kHz to 2.7 kHz. If you switch to JT-9 via the software then the radio
should move up band 2 kHz.

This is all configured in the Settings F2 menu of WSJT-X. If you need
screen shots, I can provide such.

73

Bob, K4TAX

On 7/2/2017 2:50 PM, Tom-KQ5S wrote:

KQ5S-Tom

Re: K3S Shift Setting for WSJTX

Wow the message only took 24 hours to post.

I am no expert but from what I have read it is best to select split
operations in the WSJTX settings. By doing this you can work JT9 and JT65
at the same time since WSJTX will change the split frequency to insure you
are within the passband.

I keep my WJTX mode set to JT9/JT65 and can work both without having to
change anything.

Of course I could be off in left field and if so someone will correct me.

73,
Tom - KQ5S

73,
Tom - KQ5S

On Tue, Jul 4, 2017 at 8:05 AM, Bob McGraw K4TAX <[hidden email]>
wrote:

> Why split? The K3S should be in Data A mode and should switch to Data
> when you allow WSJT-X to connect. Typical bandwidth for receive is 2.4
> kHz to 2.7 kHz. If you switch to JT-9 via the software then the radio
> should move up band 2 kHz.
>
> This is all configured in the Settings F2 menu of WSJT-X. If you need
> screen shots, I can provide such.
>
> 73
>
> Bob, K4TAX
>
>
> On 7/2/2017 2:50 PM, Tom-KQ5S wrote:
>
>> Hope this is not a dupe. I sent it over an hour ago and nothing showed
>> up.
>>
>> I am trying to tweak my WSJTX setup. What is the recommended shift for
>> the
>> K3S while running WSJTX? I have the 2.8 khz SSB filter installed. I am
>> using a width of 4 khz and using the radio in split mode.
>>
>>
>> 73,
>> Tom - KQ5S
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to [hidden email]
>>
>>
>
> ______________________________________________________________
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>
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Wes Stewart-2

Re: K3S Shift Setting for WSJTX

In reply to this post by Bob McGraw - K4TAX

Since I am being dragged, kicking and screaming, into these imaginary QSO modes
and have yet to allow my computer to talk to anyone else's computer on the air,
perhaps I shouldn't comment, but I will anyway :-) I am receiving BTW, using
WSJT-X in JT65. Depending on the tone(s), if the K3 is in split
"Settings-->Radio-->Split Operation-->Rig" the the software will command the TX
QRG to an offset that puts the tones in the "sweet spot".

It's all explained in the very helpful help file.

Wes N7WS

On 7/4/2017 6:05 AM, Bob McGraw K4TAX wrote:

> Why split? The K3S should be in Data A mode and should switch to Data when
> you allow WSJT-X to connect. Typical bandwidth for receive is 2.4 kHz to 2.7
> kHz. If you switch to JT-9 via the software then the radio should move up
> band 2 kHz.
>
> This is all configured in the Settings F2 menu of WSJT-X. If you need screen
> shots, I can provide such.
>
> 73
>
> Bob, K4TAX

KQ5S-Tom

Re: K3S Shift Setting for WSJTX

In reply to this post by KQ5S-Tom

From the WSJTX users manual:

Split Operation: Significant advantages result from using Split mode
(separate VFOs for Rx and Tx) if your radio supports it. If it does not,
WSJT-X can emulate such behavior. Either method will result in a cleaner
transmitted signal, by keeping the Tx audio always in the range 1500 to
2000 Hz so that audio harmonics cannot pass through the Tx sideband filter.
Select Rig to use the radio’s Split mode, or Fake It to have WSJT-X adjust
the VFO frequency as needed, when T/R switching occurs. Choose None if you
do not wish to use split operation.

73,
Tom - KQ5S

On Tue, Jul 4, 2017 at 3:40 AM, David Anderson <[hidden email]> wrote:

> Tom,
>
> Not a dupe, sometimes it takes a while for post to show. So don't worry.
>
> What mode are you going to be using WSJT-C on that requires a split?
>
> I have used WSJT-C here on JT65 and MSK144.
>
>
> 73 from David GM4JJJ
>
> > On 2 Jul 2017, at 20:50, Tom-KQ5S <[hidden email]> wrote:
> >
> > Hope this is not a dupe. I sent it over an hour ago and nothing showed
> up.
> >
> > I am trying to tweak my WSJTX setup. What is the recommended shift for
> the
> > K3S while running WSJTX? I have the 2.8 khz SSB filter installed. I am
> > using a width of 4 khz and using the radio in split mode.
> >
> >
> > 73,
> > Tom - KQ5S
> > ______________________________________________________________
> > Elecraft mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/elecraft
> > Help: http://mailman.qth.net/mmfaq.htm
> > Post: mailto:[hidden email]
> >
> > This list hosted by: http://www.qsl.net
> > Please help support this email list: http://www.qsl.net/donate.html
> > Message delivered to [hidden email]
>

Jim Brown-10

Re: K3S Shift Setting for WSJTX

In reply to this post by Bob McGraw - K4TAX

I agree. I use WSJT-X mostly on 6M during the summer and 160M during the
winter. On 6M, I can't use the WSJT-X split mode, because it takes over
my second VFO, preventing me from working back and forth from WSJT-X on
one VFO (and RX) and CW on the low end of the band.

The split mode in WSJT-X is simply a crutch for those who don't know (or
don't care) how to set audio levels so that distortion is not produced
in the audio chain. The link below includes simple procedures for
getting those settings right. It applies to all sorts of
computer-to-rig audio connections, not only those with a USB interface.

http://k9yc.com/USB_Interfaces.pdf

BTW -- a decent USB interface can GREATLY improve decoding of weak
signals. That link describes my testing that clearly shows that.

73, Jim K9YC

On 7/4/2017 6:05 AM, Bob McGraw K4TAX wrote:
> Why split? The K3S should be in Data A mode and should switch to Data
> when you allow WSJT-X to connect.

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KQ5S-Tom

Re: K3S Shift Setting for WSJTX

No argument but some folks, particularly those new to WSJTX, read the WSJTX
user manual and follow it. Also split mode is "encouraged" on the WSJT
group.

Split Operation: Significant advantages result from using Split mode
(separate VFOs for Rx and Tx) if your radio supports it. If it does not,
WSJT-X can emulate such behavior. Either method will result in a cleaner
transmitted signal, by keeping the Tx audio always in the range 1500 to
2000 Hz so that audio harmonics cannot pass through the Tx sideband filter.
Select Rig to use the radio’s Split mode, or Fake It to have WSJT-X adjust
the VFO frequency as needed, when T/R switching occurs. Choose None if you
do not wish to use split operation.

73,
Tom - KQ5S

On Tue, Jul 4, 2017 at 12:37 PM, Jim Brown <[hidden email]>
wrote:

> I agree. I use WSJT-X mostly on 6M during the summer and 160M during the
> winter. On 6M, I can't use the WSJT-X split mode, because it takes over my
> second VFO, preventing me from working back and forth from WSJT-X on one
> VFO (and RX) and CW on the low end of the band.
>
> The split mode in WSJT-X is simply a crutch for those who don't know (or
> don't care) how to set audio levels so that distortion is not produced in
> the audio chain. The link below includes simple procedures for getting
> those settings right. It applies to all sorts of computer-to-rig audio
> connections, not only those with a USB interface.
>
> http://k9yc.com/USB_Interfaces.pdf
>
> BTW -- a decent USB interface can GREATLY improve decoding of weak
> signals. That link describes my testing that clearly shows that.
>
> 73, Jim K9YC
>
> On 7/4/2017 6:05 AM, Bob McGraw K4TAX wrote:
>
>> Why split? The K3S should be in Data A mode and should switch to Data
>> when you allow WSJT-X to connect.
>>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

Bob McGraw - K4TAX

Re: K3S Shift Setting for WSJTX

One anomaly which I've just observed with my K3S. I did set the
software as suggested for SPLIT mode for WSJT-X / JT-65. The radio
followed as expected. I made a few contacts successfully with this
configuration. When I closed WSJT-X I noted it left the radio in SPLIT
mode. I can just see all of the confusion and frustration not to
mention unintentional QRM created by this occurrence. Another trap to
watch for.

Probably in my case, even a better reason not to use SPLIT. In other
words, it isn't idiot proof and I've been accused as being as dumb as a
box of rocks.

73

Bob, K4TAX

On 7/4/2017 1:25 PM, Tom-KQ5S wrote:

> No argument but some folks, particularly those new to WSJTX, read the WSJTX
> user manual and follow it. Also split mode is "encouraged" on the WSJT
> group.
>
> Split Operation: Significant advantages result from using Split mode
> (separate VFOs for Rx and Tx) if your radio supports it. If it does not,
> WSJT-X can emulate such behavior. Either method will result in a cleaner
> transmitted signal, by keeping the Tx audio always in the range 1500 to
> 2000 Hz so that audio harmonics cannot pass through the Tx sideband filter.
> Select Rig to use the radio’s Split mode, or Fake It to have WSJT-X adjust
> the VFO frequency as needed, when T/R switching occurs. Choose None if you
> do not wish to use split operation.
>
>
>
>
> 73,
> Tom - KQ5S
>
> O

KQ5S-Tom

Re: K3S Shift Setting for WSJTX

In reply to this post by Joe Subich, W4TV-4

Thanks Joe. Mike, W9MDB, sent me a procedure using WSJTX to determine the
cutoff points. I arrived at exactly what you are saying. I am using 1500
and find that I can copy JT9 out to 3000 and if a stronger signal out to
about 3300.

73,
Tom - KQ5S

On Tue, Jul 4, 2017 at 7:25 AM, Joe Subich, W4TV <[hidden email]> wrote:

>
> I am using a width of 4 khz and using the radio in split mode.
>>
> Width of 4 KHz is useless with a 2800 Hz SSB filter. You do not
> need (and can't use) more than 3000 - 3300 Hz.
>
> The default shift of 1500 (for DATA A) will provide relatively
> flat audio response from 300 Hz to 2800 Hz with Width at 3000 Hz.
> If you move the shift to 1700 the "flat area" of the audio pass-
> band will be about 300 to 3000 Hz.
>
> Remember, with a 2800 Hz filter the maximum bandwidth is 2800 Hz
> between the -3 dB points. Setting a wider DSP filter is not going
> to make the flat are any wider it will only allow you to see more
> of the filter skirts. If you really need the full 4 KHz get an
> AM (6 KHz) or FM (13 KHz) filter.
>
> 73,
>
> ... Joe, W4TV
>
>
> On 7/2/2017 3:50 PM, Tom-KQ5S wrote:
>
>> Hope this is not a dupe. I sent it over an hour ago and nothing showed
>> up.
>>
>> I am trying to tweak my WSJTX setup. What is the recommended shift for
>> the
>> K3S while running WSJTX? I have the 2.8 khz SSB filter installed. I am
>> using a width of 4 khz and using the radio in split mode.
>>
>>
>> 73,
>> Tom - KQ5S
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to [hidden email]
>>
>> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

Richard Lamont

Re: K3S Shift Setting for WSJTX

In reply to this post by Jim Brown-10

On 04/07/17 18:37, Jim Brown wrote:

> The split mode in WSJT-X is simply a crutch for those who don't know (or
> don't care) how to set audio levels so that distortion is not produced
> in the audio chain.
Sorry, but that's nonsense.

With a strong signal, just 1% distortion will produce audio harmonics
that are only 40-ish dB down on the fundamental. That's plenty to cause
QRM. With these modes it's possible to have work a station that's 60 dB
down on another just a few Hz away. WSJT-X, being based on 16-bit
digital audio, has an inherently high dynamic range.

The split mode exists (a) to enable people to work over a wider range of
frequencies than a single SSB channel, and (b) to ensure that the Tx
audio frequency is always at least 1500 Hz, ensuring that *low-level*
harmonics get filtered out. Even with a clean TX and audio levels set
just so, it's well worth having that extra filtering in place.

73,
Richard G4DYA
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ve3ibw

Re: K3S Shift Setting for WSJTX

In reply to this post by Bob McGraw - K4TAX

Actually, my experience is different. If I transmit at the edges of the
bandpass, my signal is attenuated due to the bandpass of the output stage.
I hope I am saying this correctly. This is why I use split to ensure that
the signal I transmit engages the full power of the KX3.

Now, I have read many times in this forum that the setup of audio based
digital modes only needs to set the audio so you get 4 bars of alc (5th
flickering) and then set the output power to 5w (in my case that is what I
use). You set these independently of one another. Fine. I have done
that. But, I have observed that if I don't use split mode and I respond to
a cq at the edges of the bandpass (e.g., 200-300hz or 2500-2700hz), my
signal is noticeably weaker.

Have I misconfigured something on the KX3? The USB sound card I am using
is many times wider than a typical USB signal.

regards,
Brian
VE3IBW

On Tue, Jul 4, 2017 at 2:38 PM, Bob McGraw K4TAX <[hidden email]>
wrote:

> One anomaly which I've just observed with my K3S. I did set the software
> as suggested for SPLIT mode for WSJT-X / JT-65. The radio followed as
> expected. I made a few contacts successfully with this configuration.
> When I closed WSJT-X I noted it left the radio in SPLIT mode. I can just
> see all of the confusion and frustration not to mention unintentional QRM
> created by this occurrence. Another trap to watch for.
>
> Probably in my case, even a better reason not to use SPLIT. In other
> words, it isn't idiot proof and I've been accused as being as dumb as a box
> of rocks.
>
> 73
>
> Bob, K4TAX
>
>
> On 7/4/2017 1:25 PM, Tom-KQ5S wrote:
>
>> No argument but some folks, particularly those new to WSJTX, read the
>> WSJTX
>> user manual and follow it. Also split mode is "encouraged" on the WSJT
>> group.
>>
>> Split Operation: Significant advantages result from using Split mode
>> (separate VFOs for Rx and Tx) if your radio supports it. If it does not,
>> WSJT-X can emulate such behavior. Either method will result in a cleaner
>> transmitted signal, by keeping the Tx audio always in the range 1500 to
>> 2000 Hz so that audio harmonics cannot pass through the Tx sideband
>> filter.
>> Select Rig to use the radio’s Split mode, or Fake It to have WSJT-X adjust
>> the VFO frequency as needed, when T/R switching occurs. Choose None if you
>> do not wish to use split operation.
>>
>>
>>
>>
>> 73,
>> Tom - KQ5S
>>
>> O
>>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

Regards,
Brian
VE3IBW

Richard Lamont

Re: K3S Shift Setting for WSJTX

In reply to this post by KQ5S-Tom

On 04/07/17 19:38, Bob McGraw K4TAX wrote:

> One anomaly which I've just observed with my K3S. I did set the
> software as suggested for SPLIT mode for WSJT-X / JT-65. The radio
> followed as expected. I made a few contacts successfully with this
> configuration. When I closed WSJT-X I noted it left the radio in SPLIT
> mode. I can just see all of the confusion and frustration not to
> mention unintentional QRM created by this occurrence. Another trap to
> watch for.
>
> Probably in my case, even a better reason not to use SPLIT. In other
> words, it isn't idiot proof and I've been accused as being as dumb as a
> box of rocks.

I use a macro to unset all the WSJT-X-specific settings on my rig when I
switch to another mode. Among other things it unsplits and turns AGC
back on.

73,
Richard G4DYA
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Jim Brown-10

Re: K3S Shift Setting for WSJTX

In reply to this post by Richard Lamont

Richard,

Not nonsense at all. WSJT-X is VERY robust in the ability to reject
this sort of QRM. The screen grab below is a great example. I continue
to be amazed by the decoding in WSJT-X. About 10 days ago, W0OGH
accidentally got out of sync with JA7QVI, calling on his TX cycle, and
on the same frequency. As this screen grab clearly shows, W0OGH was 9 dB
stronger on the 0053Z cycle and 12 dB stronger on the 0055Z cycle, yet
both signals were decoded without error!

During a wonderful 6M opening this past Friday evening west coast time,
I had a LOT of JT65/JT9 passes with more than 20 clean decodes on each
pass. I regularly see decodes in the -20 to -28 range, even with very
strong signals capturing the AGC. It's only necessary to keep peak
signal levels to the A/D below digital clip.

73, Jim K9YC

= = = = = = = = = =

0053 -23 0.3 2788 @ K1JT W7AH DM42

0053 -14 0.1 817 # JA7QVI W0OGH DM52

0053 -24 0.0 1274 # CQ DX JF3DRI PM74

0053 -14 0.2 1590 # N4GBK N6ML CM97

0053 -23 0.6 817 # CQ DX JA7QVI QM08

------------------------------------- 6m

0055 -7 0.1 817 # JA7QVI W0OGH DM52

0055 -22 -0.0 1274 # CQ DX JF3DRI PM74

0055 -16 0.2 1588 # N4GBK N6ML R-07

0055 -19 0.6 816 # N6WS JA7QVI R-06

On 7/4/2017 1:47 PM, Richard Lamont wrote:

> On 04/07/17 18:37, Jim Brown wrote:
>
>> The split mode in WSJT-X is simply a crutch for those who don't know (or
>> don't care) how to set audio levels so that distortion is not produced
>> in the audio chain.
> Sorry, but that's nonsense.
>
> With a strong signal, just 1% distortion will produce audio harmonics
> that are only 40-ish dB down on the fundamental. That's plenty to cause
> QRM. With these modes it's possible to have work a station that's 60 dB
> down on another just a few Hz away. WSJT-X, being based on 16-bit
> digital audio, has an inherently high dynamic range.
>
> The split mode exists (a) to enable people to work over a wider range of
> frequencies than a single SSB channel, and (b) to ensure that the Tx
> audio frequency is always at least 1500 Hz, ensuring that *low-level*
> harmonics get filtered out. Even with a clean TX and audio levels set
> just so, it's well worth having that extra filtering in place.
>
> 73,
> Richard G4DYA
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

Richard Lamont

Re: K3S Shift Setting for WSJTX

On 04/07/17 22:56, Jim Brown wrote:

> Richard,
>
> Not nonsense at all. WSJT-X is VERY robust in the ability to reject
> this sort of QRM. The screen grab below is a great example. I continue
> to be amazed by the decoding in WSJT-X. About 10 days ago, W0OGH
> accidentally got out of sync with JA7QVI, calling on his TX cycle, and
> on the same frequency. As this screen grab clearly shows, W0OGH was 9 dB
> stronger on the 0053Z cycle and 12 dB stronger on the 0055Z cycle, yet
> both signals were decoded without error!
>
> During a wonderful 6M opening this past Friday evening west coast time,
> I had a LOT of JT65/JT9 passes with more than 20 clean decodes on each
> pass. I regularly see decodes in the -20 to -28 range, even with very
> strong signals capturing the AGC. It's only necessary to keep peak
> signal levels to the A/D below digital clip.

That's receive levels. I was talking about Tx distortion.

While it's certainly the case that WSJT-X's two-pass decoder can
*sometimes* decode weak signals underneath overlapping strong ones, this
isn't always the case and it can never be a magic cure all. That would
have Claude and Harry spinning in their graves. Any kind of spurious
crud will raise the noise floor, which is always a bad thing.

Also, harmonics really clutter the waterfall. A JT65 signal on, say 700
Hz, will appear between 700-878 Hz. The second and third harmonics will
appear between 1400-1756 and 2100-2634 Hz. Just one distorted JT65
signal easily mess up over a kHz of bandwidth in total. With a busy band
this can turn the display into an incomprehensible mush.

Also, audio harmonics of JT65 signals can spread into the part of the
band used by JT9, which does not have a two-pass decoder.

The WSJT-X developers are a *very* clever team of 25 people, led by a
Nobel-prize winning professor of physics at Princeton, who have
considered all this stuff over many years with a forensic, mathematical
rigour of the kind that most of us can only guess at. If they say that
it's a good idea to keep TX audio above 1500 Hz, I think I'll trust
their word over yours.

73,
Richard G4DYA

73,
Richard G4DYA

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Christopher Hoover

Re: K3S Shift Setting for WSJTX

I use fake it mode for split on my K3S, data mode, 4.00 on bandwidth, 1.5
for shift. Works great.

The rig control for WSJT-X split is not reliable for me. I build from
tip of tree from the repo with either hamlib-3.1 or hamlib git, so it is
certainly possible I am seeing a regression that is not in older, stable
releases. (I looked at the code that handles split mode to try to fix it
... shivers.)

73 de AI6KG

On Tue, Jul 4, 2017 at 3:43 PM, Richard Lamont <[hidden email]> wrote:

> On 04/07/17 22:56, Jim Brown wrote:
> > Richard,
> >
> > Not nonsense at all. WSJT-X is VERY robust in the ability to reject
> > this sort of QRM. The screen grab below is a great example. I continue
> > to be amazed by the decoding in WSJT-X. About 10 days ago, W0OGH
> > accidentally got out of sync with JA7QVI, calling on his TX cycle, and
> > on the same frequency. As this screen grab clearly shows, W0OGH was 9 dB
> > stronger on the 0053Z cycle and 12 dB stronger on the 0055Z cycle, yet
> > both signals were decoded without error!
> >
> > During a wonderful 6M opening this past Friday evening west coast time,
> > I had a LOT of JT65/JT9 passes with more than 20 clean decodes on each
> > pass. I regularly see decodes in the -20 to -28 range, even with very
> > strong signals capturing the AGC. It's only necessary to keep peak
> > signal levels to the A/D below digital clip.
>
> That's receive levels. I was talking about Tx distortion.
>
> While it's certainly the case that WSJT-X's two-pass decoder can
> *sometimes* decode weak signals underneath overlapping strong ones, this
> isn't always the case and it can never be a magic cure all. That would
> have Claude and Harry spinning in their graves. Any kind of spurious
> crud will raise the noise floor, which is always a bad thing.
>
> Also, harmonics really clutter the waterfall. A JT65 signal on, say 700
> Hz, will appear between 700-878 Hz. The second and third harmonics will
> appear between 1400-1756 and 2100-2634 Hz. Just one distorted JT65
> signal easily mess up over a kHz of bandwidth in total. With a busy band
> this can turn the display into an incomprehensible mush.
>
> Also, audio harmonics of JT65 signals can spread into the part of the
> band used by JT9, which does not have a two-pass decoder.
>
> The WSJT-X developers are a *very* clever team of 25 people, led by a
> Nobel-prize winning professor of physics at Princeton, who have
> considered all this stuff over many years with a forensic, mathematical
> rigour of the kind that most of us can only guess at. If they say that
> it's a good idea to keep TX audio above 1500 Hz, I think I'll trust
> their word over yours.
>
> 73,
> Richard G4DYA
>
>
> 73,
> Richard G4DYA
>
>
>
>
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Jim Brown-10

Re: K3S Shift Setting for WSJTX

In reply to this post by Richard Lamont

On 7/4/2017 3:43 PM, Richard Lamont wrote:
> That's receive levels. I was talking about Tx distortion.

The distortion I measured was for TX mode -- sound interface to radio.

Richard -- I'm a Fellow of the Audio Engineering Society, BSEE, retired,
worked in both audio and broadcasting. I'm VERY aware of distortion
products and the mechanisms that produce them. I also TAUGHT this stuff.
Your concerns are overblown.

FWIW, I am FAR more concerned with distortions produced in ham gear at RF.

73, Jim K9YC

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Nate Bargmann

Re: K3S Shift Setting for WSJTX

In reply to this post by Christopher Hoover

* On 2017 04 Jul 19:03 -0500, Christopher Hoover wrote:
> I use fake it mode for split on my K3S, data mode, 4.00 on bandwidth, 1.5
> for shift. Works great.
>
> The rig control for WSJT-X split is not reliable for me. I build from
> tip of tree from the repo with either hamlib-3.1 or hamlib git, so it is
> certainly possible I am seeing a regression that is not in older, stable
> releases. (I looked at the code that handles split mode to try to fix it
> ... shivers.)

I built WSJT-X 1.7 six months ago from the distribution tarball on this
Devuan Jessie box and WSJT-X has been rock solid reliable in split mode
and my K3 with DATA A mode. Just worked a few more stations this
evening on 15 and 17m.

73, Nate, N0NB

--

"The optimist proclaims that we live in the best of all
possible worlds. The pessimist fears this is true."

Ham radio, Linux, bikes, and more: http://www.n0nb.us
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Bob McGraw - K4TAX

Re: K3S Shift Setting for WSJTX

In reply to this post by Jim Brown-10

I fully agree with Jim, K9YC on the point of distortion. In fact there
are two signal paths in which distortion will affect ones results.
Certainly audio distortion on the TX side will affect the quality of
ones transmitted signal and distortion on the receive will affect ones
decode quality.

In my Windows 10 environment I find the Speaker level {USB Audio CODEC}
best at about 50% or - 10 dB. Also in this pane, be sure to disable
all enhancements. This allows the PWR fader for WSJT-X to operate
about 50% or mid range of its travel. The Line gain on the K3S runs
about 25 for 4 bars solid on the ALC and the 5th bar flickering in Data
A mode. Adjust actual RF power output via the PWR control on the radio.

On the receive end of WSJT-X, I find the Recording device level to be
optimized for the USB CODEC at 0 dB with the K3S line out level at the
normal / default of 010. Excessive USB CODAC gain at this point can
over drive the audio stage causing distortion and one will sacrifice
decode quality. The WSJT-X digital gain runs about the 3rd to 4th bar
from the bottom and the level indicator nominally at about 25 dB to 35
dB depending on band noise and signals.

Should you find any of your controls at an extreme position, I would be
concerned that something is not correct up or down stream in the audo paths.

73

Bob, K4TAX

On 7/4/2017 7:33 PM, Jim Brown wrote:

> On 7/4/2017 3:43 PM, Richard Lamont wrote:
>> That's receive levels. I was talking about Tx distortion.
>
> The distortion I measured was for TX mode -- sound interface to radio.
>
> Richard -- I'm a Fellow of the Audio Engineering Society, BSEE,
> retired, worked in both audio and broadcasting. I'm VERY aware of
> distortion products and the mechanisms that produce them. I also
> TAUGHT this stuff. Your concerns are overblown.
>
> FWIW, I am FAR more concerned with distortions produced in ham gear at
> RF.
>
> 73, Jim K9YC
>
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Richard Lamont

Re: K3S Shift Setting for WSJTX

In reply to this post by KQ5S-Tom

On 05/07/17 01:33, Jim Brown wrote:

> Richard -- I'm a Fellow of the Audio Engineering Society, BSEE, retired,
> worked in both audio and broadcasting. I'm VERY aware of distortion
> products and the mechanisms that produce them. I also TAUGHT this stuff.
> Your concerns are overblown.

Thank you for your rigorous, quantified mathematical proof.

Clearly the JT65 transmitted harmonics I've seen, as received on my K3S,
which blotted out the weak JT9 station I was trying to work at around
-27, must have been a figment of my imagination.

73,
Richard G4DYA
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