[600MRG] LF: SlowJT9 update (v0.9.10): tuning issue solved

Wed Nov 21 11:14:06 EST 2018

It doesn't seem to be my day ;-)

1. Fed the soundcard input with a 600Hz sine tone while SlowJT9 is running in JT9-1 mode,

should read

1. Fed the soundcard input with a 600Hz sine tone while SlowJT9 is running in JT9-2 mode,

73, Rik

________________________________
Van: rsgb_lf_group at yahoogroups.co.uk <rsgb_lf_group at yahoogroups.co.uk> namens Rik Strobbe rik.strobbe at kuleuven.be [rsgb_lf_group] <rsgb_lf_group at yahoogroups.co.uk>
Verzonden: woensdag 21 november 2018 16:30
Aan: rsgb_lf_group at blacksheep.org; 600MRG at mailman.qth.net; rsgb_lf_group at yahoogroups.co.uk
Onderwerp: [rsgb_lf_group] Re: LF: SlowJT9 update (v0.9.10): tuning issue solved

Oops, the first sentence should read:

unfortunately I have no working WSJT-X version ...

73, Rik

________________________________
Van: rsgb_lf_group at yahoogroups.co.uk <rsgb_lf_group at yahoogroups.co.uk> namens Rik Strobbe rik.strobbe at kuleuven.be [rsgb_lf_group] <rsgb_lf_group at yahoogroups.co.uk>
Verzonden: woensdag 21 november 2018 16:12
Aan: rsgb_lf_group at blacksheep.org; 600MRG at mailman.qth.net; rsgb_lf_group
Onderwerp: [rsgb_lf_group] Re: LF: SlowJT9 update (v0.9.10): tuning issue solved

Hello Paul,

unfortunately I have now working WSJT-W version that supports the JT9 submodes.
So I had to rely on the parameters given in appendix B of the WSJT-X 1.0 users guide (http://physics.princeton.edu/pulsar/K1JT/WSJT-X_Users_Guide.pdf).
[cid:cd94d96b-dfff-49cf-8001-3972e5a6a3b5]

Further I had to assume that for all submodes the transmissions start a 1 seconds after the minute, as it is for JT9(-1).

The check version 0.9.10 I did 2 things:
-
1. Fed the soundcard input with a 600Hz sine tone while SlowJT9 is running in JT9-1 mode, with audio saving on (that way the audio files used to feed the JT9 decoder are saved on disk).
In this audio file I could see a nice sine at 1333Hz, as expected (with the original parameters the conversion rate between JT9-2 and JT9-1 is 15360/912 = 2.222, so 600Hz becomes 2.222*600 = 1333Hz). This is at least a strong indication that the JT9-2 to JT9(-1) conversion is done correctly.
For those interested in the details: due the the odd conversion rate, each 2.222 JT9-2 samples now have to be averaged to 1 JT9-1 sample, I will explain in a separate mail how I did this.

2. Recorded the JT9-2 signal generated by SlowJT-9, added (a lot of) noise to it and then played it back tp SlowJT9. I did this for the both JT9-2 version. For both versions I had a sloid copy down to -30dB. But as said earlier: it was just a short test. Good enough to constate that the decoding of the original JT9-2 is more or less as good as the earlier version, but certainly not good enough to confirm the (theoretical) S/N gain of about 0.5dB.

About the frequencies: the maximum frequency that the JT9 decoder will handle is 5000Hz. This means that for JT9-2 the maximum frequency is 5000/2.2222 = 2250 Hz (but SlowJT9 has a general upper limit of 1400Hz to keep out of the WSPT band).
For JT9-5 the maximum frequency is 5000*6912/40960 = 843 Hz and for JT9-10 it is 5000*6912/82944 = 416Hz!

An important remark: I just noticed that the baurdrate conversion is SlowJT9 is OK, but not the entire timing. As a JT9-2 transmission now also starts at 1 second, after conversion to JT9(-1) it will start at 0.45 seconds (1/2.2222), thus an error of 0.55 seconds. The JT9 decoder should be able to handle this without too moch loss. But for JT9-5 and JT9-10 the error will become larger!. I will correct this in the next version of SlowJT9.

73, Rik  ON7YD - OR7T

________________________________________
Van: owner-rsgb_lf_group at blacksheep.org <owner-rsgb_lf_group at blacksheep.org> namens N1BUG <paul at n1bug.com>
Verzonden: woensdag 21 november 2018 13:47
Aan: rsgb_lf_group at blacksheep.org; 600MRG at mailman.qth.net; rsgb_lf_group
Onderwerp: Re: LF: SlowJT9 update (v0.9.10): tuning issue solved

Hello Rik, all,

Yesterday I could do some tests with my QRP Labs U3S transmitting,
SlowJT9 receiving. I used a lot of attenuation between U3S and TX
antenna. Then there is another 30 or 40 dB lost between the TX
antenna and RX antenna. The result was that in JT9-1 I had a signal
which was most of the time -27, occasionally -26 or -28.

I then switched to JT9-2. I confirm SlowJT9 will decode these
transmissions using the old baud rate. SNR was now mostly -29, so I
am not sure this is reporting correctly. SNR should have remained
the same when changing modes.

I then switched to JT9-5. I confirm SlowJT9 will decode this OK. SNR
was now mostly -30, again does not seem logical to me.

More tests are needed to see if I always get the same SNR results on
the different modes! There was not enough time to run enough cycles
of each mode to eliminate random chance.

I tried JT9-10 but I could not get any decode. I assume for this
mode the audio frequency must be under 500 Hz? I tried 470 Hz but
nothing. The signal was clearly visible on the waterfall but did not
decode.

Later, K3MF upgraded to the new version and made some JT9-2
transmissions on 2200m. His signal was strong as usual, but I could
not decode him at all. I could confirm that his transmission was
occupying the correct amount of time for the slower baud rate, but
it could be decoded.

That is all for now. I will continue my SNR tests between the submodes.

73,
Paul N1BUG

__._,_.___
________________________________
Posted by: Rik Strobbe <rik.strobbe at kuleuven.be>
________________________________
Reply via web post<https://uk.groups.yahoo.com/neo/groups/rsgb_lf_group/conversations/messages/8199;_ylc=X3oDMTJxcWM1ZWxlBF9TAzk3NDkwNTA1BGdycElkAzg1MDgwODk1BGdycHNwSWQDMTY5MDA2MzEwOARtc2dJZAM4MTk5BHNlYwNmdHIEc2xrA3JwbHkEc3RpbWUDMTU0MjgxNDIzMw--?act=reply&messageNum=8199>        •       Reply to sender <mailto:rik.strobbe at kuleuven.be?subject=Re%3A%20LF%3A%20SlowJT9%20update%20%28v0%2E9%2E10%29%3A%20tuning%20issue%20solved>      •       Reply to group <mailto:rsgb_lf_group at yahoogroups.co.uk?subject=Re%3A%20LF%3A%20SlowJT9%20update%20%28v0%2E9%2E10%29%3A%20tuning%20issue%20solved>       •       Start a new topic<https://uk.groups.yahoo.com/neo/groups/rsgb_lf_group/conversations/newtopic;_ylc=X3oDMTJmNjFuN3E0BF9TAzk3NDkwNTA1BGdycElkAzg1MDgwODk1BGdycHNwSWQDMTY5MDA2MzEwOARzZWMDZnRyBHNsawNudHBjBHN0aW1lAzE1NDI4MTQyMzM->        •       Messages in this topic<https://uk.groups.yahoo.com/neo/groups/rsgb_lf_group/conversations/topics/8187;_ylc=X3oDMTM1MDN2NG9zBF9TAzk3NDkwNTA1BGdycElkAzg1MDgwODk1BGdycHNwSWQDMTY5MDA2MzEwOARtc2dJZAM4MTk5BHNlYwNmdHIEc2xrA3Z0cGMEc3RpbWUDMTU0MjgxNDIzMwR0cGNJZAM4MTg3> (7)
Visit Your Group<https://uk.groups.yahoo.com/neo/groups/rsgb_lf_group/info;_ylc=X3oDMTJmcmo4ZnJsBF9TAzk3NDkwNTA1BGdycElkAzg1MDgwODk1BGdycHNwSWQDMTY5MDA2MzEwOARzZWMDdnRsBHNsawN2Z2hwBHN0aW1lAzE1NDI4MTQyMzM->

  *   New Members<https://uk.groups.yahoo.com/neo/groups/rsgb_lf_group/members/all;_ylc=X3oDMTJnaTdoa2QwBF9TAzk3NDkwNTA1BGdycElkAzg1MDgwODk1BGdycHNwSWQDMTY5MDA2MzEwOARzZWMDdnRsBHNsawN2bWJycwRzdGltZQMxNTQyODE0MjMz> 1

[Yahoo! Groups]<https://uk.groups.yahoo.com/neo;_ylc=X3oDMTJlNmV1azJ2BF9TAzk3NDkwNTAzBGdycElkAzg1MDgwODk1BGdycHNwSWQDMTY5MDA2MzEwOARzZWMDZnRyBHNsawNnZnAEc3RpbWUDMTU0MjgxNDIzMw-->
• Privacy<https://info.yahoo.com/privacy/uk/yahoo/groups/details.html> • Unsubscribe<mailto:rsgb_lf_group-unsubscribe at yahoogroups.co.uk?subject=Unsubscribe> • Terms of Use<https://info.yahoo.com/legal/uk/yahoo/utos/en-gb/details.html>

SPONSORED LINKS
document.write('<https://eu.y.atwola.com/?adlink|1065.1|2590140|0|16|AdId=-3;BnId=0;itime=814233835;kvmn=y100000;kvssp=brxd;kvpgcolo=bf1;kvadtc%5Fdvmktname=unknown;kvadtc%5Fdvosplt=unknown;kvadtc%5Fdvbrand=unknown;kvadtc%5Fdvtype=unknown;kvadtc%5Fdvmodel=unknown;kvrepo%5Fdvosplt=unknown;kvadtc%5Fdvosversion=UNKNOWN;kvadtc%5Fcrbrand=wifi%5Fus;kvadtc%5Fcrmcc=UNKNOWN;kvadtc%5Fcrmnc=UNKNOWN;kvadtc%5Fcrcountry=us;kvadtc%5Fcontype=wifi;gdpr=0;adclntid=1004;spaceid=1690063108;>');
document.write('<https://eu.y.atwola.com/?adlink|1065.1|2590140|0|16|AdId=-3;BnId=0;itime=814233836;kvmn=y100000;kvssp=brxd;kvpgcolo=bf1;kvadtc%5Fdvmktname=unknown;kvadtc%5Fdvosplt=unknown;kvadtc%5Fdvbrand=unknown;kvadtc%5Fdvtype=unknown;kvadtc%5Fdvmodel=unknown;kvrepo%5Fdvosplt=unknown;kvadtc%5Fdvosversion=UNKNOWN;kvadtc%5Fcrbrand=wifi%5Fus;kvadtc%5Fcrmcc=UNKNOWN;kvadtc%5Fcrmnc=UNKNOWN;kvadtc%5Fcrcountry=us;kvadtc%5Fcontype=wifi;gdpr=0;adclntid=1004;spaceid=1690063108;>');
document.write('<https://eu.y.atwola.com/?adlink|1065.1|2590140|0|16|AdId=-3;BnId=0;itime=814233837;kvmn=y100000;kvssp=brxd;kvpgcolo=bf1;kvadtc%5Fdvmktname=unknown;kvadtc%5Fdvosplt=unknown;kvadtc%5Fdvbrand=unknown;kvadtc%5Fdvtype=unknown;kvadtc%5Fdvmodel=unknown;kvrepo%5Fdvosplt=unknown;kvadtc%5Fdvosversion=UNKNOWN;kvadtc%5Fcrbrand=wifi%5Fus;kvadtc%5Fcrmcc=UNKNOWN;kvadtc%5Fcrmnc=UNKNOWN;kvadtc%5Fcrcountry=us;kvadtc%5Fcontype=wifi;gdpr=0;adclntid=1004;spaceid=1690063108;>');
.

__,_._,___
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/600mrg/attachments/20181121/6975ef89/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: pastedImage.png
Type: image/png
Size: 41797 bytes
Desc: pastedImage.png
URL: <http://mailman.qth.net/pipermail/600mrg/attachments/20181121/6975ef89/attachment.png>