From: Rik Strobbe <rik.strobbe@kuleuven.be>
To: "rsgb_lf_group@blacksheep.org" <rsgb_lf_group@blacksheep.org>,
        "rsgb_lf_group@yahoogroups.co.uk" <rsgb_lf_group@yahoogroups.co.uk>
Thread-Topic: [rsgb_lf_group] Re: LF: JT9-2 and JT9-5 mode application
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Date: Sat, 10 Nov 2018 19:26:12 +0000
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Subject: Re: [rsgb_lf_group] Re: LF: JT9-2 and JT9-5 mode application
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Hi Paul, all,

"I don't know if it is possible to run
two instances of SlowJT9 with different settings?"

Your question triggered an idea: it should be possible (and even not very difficult) to decode JT9(-1), JT9-2 and JT9-5 simultaneously in SlowJT9!
Assume a 10 minute periode (from 12h00 - 12h10). In these 10 minutes there are 10 JT9(-1) TX periods, 5 JT9-2 TX periods and 2 JT9-5 TX periods.
There will always be at least 10 seconds difference between the end of any 2 transmissions. That should be sufficient to finish the decoding of one transmission before the next decoding starts.
That way there no "embarras du choix"  :-)

73, Rik  ON7YD - OR7T

________________________________________
Van: owner-rsgb_lf_group@blacksheep.org <owner-rsgb_lf_group@blacksheep.org> namens N1BUG <paul@n1bug.com>
Verzonden: zaterdag 10 november 2018 19:26
Aan: rsgb_lf_group@blacksheep.org; rsgb_lf_group@yahoogroups.co.uk
Onderwerp: Re: [rsgb_lf_group] Re: LF: JT9-2 and JT9-5 mode application

Hello Rik,

It has been a long time since I read the official WSPR-15 protocol
specification but your description sounds correct. I do remember it
is 0.8 Hz bandwidth.

Today I finally had time to install SlowJT9. It seems all the test
activity so far is on MF JT9-2 so I will monitor that starting
tonight. I have some work left to get my station back to QSO capable
but when I do I will try to make some MF QSOs with it, including TA
if there is interest.

My main interest is JT9-5 on LF but I have to find someone
interested in trying to test that. If anyone wants to transmit JT9-5
on LF I will switch to that. I don't know if it is possible to run
two instances of SlowJT9 with different settings?

73,
Paul N1BUG


On 11/10/18 9:36 AM, Rik Strobbe wrote:
> ​​Hello Paul,
>
>
> I cannot find the WSPR15 specs right away, but I assume that is
> is just a "stretched" version of WSPR(2).
>
> In that case it would be 4-FSK at 0.195 Bd and a tone spacing of
> 0.195 Hz (0.8 Hz bandwidth).
>
> JT9-15 would be 9-FSK at 0.116 Bd and a tone spacing of 0.116 Hz
> (1 Hz bandwidth).
>
> Due to the smaller tone spacing I would assume that JT9-15 will
> be more vulnerable to frequency instabilities than WSPR15.
>
> With the JT9 specs, JT9-10 would have 0.174 Hz tone spacing,
> close to  the 0.195 Hz of WSPR15.
>
> But before implementing this it would be interesting to do some
> TA tests ising JT9-2 (where the S/N should be close to WSPR) and
> JT9-5 (4 dB better than WSPR ?)
>
>
> 73, Rik  ON7YD
>
>
>
> ________________________________ Van:
> rsgb_lf_group@yahoogroups.co.uk <rsgb_lf_group@yahoogroups.co.uk>
> namens N1BUG paul@n1bug.com [rsgb_lf_group]
> <rsgb_lf_group@yahoogroups.co.uk> Verzonden: donderdag 8 november
> 2018 23:42 Aan: rsgb_lf_group@blacksheep.org;
> rsgb_lf_group@yahoogroups.co.uk Onderwerp: Re: [rsgb_lf_group]
> Re: LF: JT9-2 and JT9-5 mode application
>
>
>
> Hi Rik,
>
> I do not know the symbol lengths for JT9 slow and I do not know
> how it compares to WSPR about frequency stability requirements.
>
> From my experiment last winter I can say that on LF WSPR15 often
> gets across the pond when WSPR2 cannot. Clearly for WSPR mode,
> 15 minutes is no problem. Of course, maybe it's different for
> JT9. It was very interesting to see the success of WSPR15. That
> was what got me started thinking about slow versions of JT9
> again.
>
> I would be more concerned about stability of my equipment. The
> homebrew stuff is probably OK but the rather expensive
> transceiver used to drive the TX converters has a terrible TCXO.
> I never had much incentive to work on trying to fix it, but if
> JT9 slow becomes popular and if it needs better stability this
> will give me all the incentive needed! :)
>
> Yes of course JT9-86400 for Stefan! ;-)
>
> 73, Paul N1BUG
>
> On 11/8/18 5:12 PM, Rik Strobbe wrote:
>> Hi Paul,
>>
>> Adding even slower modes in the application is not difficult.
>> But the slower we go the more stringent the frequency
>> stability requirements are. For groundwave this is limited by
>> the TX and RX stability, but for skywave propagation the mood
>> changes of miss ionosphere could be nefast. 136 kHz might be
>> better suited for JT-10 ot JT-30 than 472kHz. Stefan might be
>> interested in JT-86400 (one message a day) for ULF ;-)
>>
>> About JT9 coding: for this I am using another exe file of the
>> WSJT-X suite. It seems to work fine, both for free and
>> structured messages.
>>
>> 73, Rik ON7YD - OR7T
>>
>>
>> ________________________________________ Van:
>> rsgb_lf_group@yahoogroups.co.uk
>> <rsgb_lf_group@yahoogroups.co.uk> namens N1BUG paul@n1bug.com
>> [rsgb_lf_group] <rsgb_lf_group@yahoogroups.co.uk> Verzonden:
>> donderdag 8 november 2018 22:57 Aan:
>> rsgb_lf_group@blacksheep.org; rsgb_lf_group@yahoogroups.co.uk
>> Onderwerp: [rsgb_lf_group] Re: LF: JT9-2 and JT9-5 mode
>> application
>>
>> Hello Rik,
>>
>> I am very interested in this! Thank you very much for your
>> work! Tomorrow I will download the program.
>>
>> I think we badly need these slow modes for the average LF
>> operators (which is most of us at least on this side of the
>> pond).
>>
>> If the beta tests are successful, would it be possible to add
>> JT9-10 and perhaps even JT9-30? For trans-Atlantic QSOs I
>> think these could be very helpful.
>>
>> How did you transmit JT9-2 signals for the QSOs? I can do that
>> with my U3S but it can only send free text messages limited to
>> 13 characters. It cannot send the packed messages normally
>> used for QSOs.
>>
>> 73, Paul N1BUG