Re: LF: AW: DF2JP JT9-1 137.445 kHz - clock timing!

["Markus Vester" <markusvester@aol.com>]

The clock error was indeed the culprit!

 

I took the non-decoding 10:26 file and used a hex editor to create slightly time-shifted versions by inserting blocks of 16384 zeroes (about 0.68 seconds) after the wav header. The files with 0.68 and 1.36 s extra delay were instantly decoded, and the relative time shift is shown correctly. The other files which were outside this narrow window do get sync points but detected frequency and DT are wrong, and nothing is dcoded.

 

http://df6nm.bplaced.net/wsjt/jt9-2_121104/121104_1026_abcd.png

 

Bottom line: I think you have to get the clock to better than about half a second, which is much tighter than WSPR. This may be difficult if extra audio pre/preprocessing is employed.

 

Best 73,

Markus (DF6NM)

From: Markus Vester

Sent: Sunday, November 04, 2012 2:22 PM

To: rsgb_lf_group@blacksheep.org

Subject: Re: LF: AW: DF2JP JT9-1 137.445 kHz

Thanks a lot Joe, that was fun! Thanks also to Ko for the nice SWL (or LWL?) report.

 

This is what I got here...

 

1238  10  -19   0.2 1950.92  0.00   DF2JP JO31JG         
1242  10  -18   0.1 1950.92  0.00   DF2JP JO31JG         
1246  10  -19  -0.1 1951.03  0.00
1250  10  -18   0.2 1951.00  0.00   DF6NM DF2JP R-14     
1254  10  -17   0.2 1950.92  0.00   TNX MARKUS 73        
1258  10  -17   0.1 1950.92  0.00   DF2JP JO31JG         
1302  10  -18   0.4 1951.00  0.00   DF2JP JO31JG         

When I first called I had just replaced the TX coil and it was not yet in resonance, with current about 1.8 instead of the later 3.8 A, which explains the -21 dB. No idea why it was -10 at 12:52.

 

Before the decodes became successful, I had restarted the NTP clock setting software. It measured the clock offset as -0.9 seconds, and corrected it to (nominally) zero. Could this really have made the difference?

 

Best 73,

Markus (DF6NM)

From: Joe

Sent: Sunday, November 04, 2012 2:03 PM

To: rsgb_lf_group@blacksheep.org

Subject: AW: LF: AW: DF2JP JT9-1 137.445 kHz

Hi Marcus,

 

 Well, no problem to catch you, but look at the difference -21dB to -10dB

1240 10 -21 0.2 1423.00 0.00 DF2JP DF6NM -16

1244 10 -14 0.3 1423.00 0.00 DF2JP DF6NM -16

1248 10 -14 0.0 1423.00 0.00 DF2JP DF6NM -16

1252 10 -10 0.1 1423.26 0.00 DF2JP DF6NM RRR

1256 10 -14 0.2 1423.00 0.00 GD JOE NOW FB

 

So now watching F1, back in 2hours.

 

73 Joe

 

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Von: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org] Im Auftrag von Markus Vester
Gesendet: Sonntag, 4. November 2012 13:34
An: rsgb_lf_group@blacksheep.org
Betreff: Re: LF: AW: DF2JP JT9-1 137.445 kHz

 

Joe,

 

consistent decodes since 11:58... if only I knew why!

 

1158  10  -18  -0.1 1950.92  0.00   DF2JP JO31JG         
1200   2  -27   0.0 1941.01  0.00
1202  10  -20   0.2 1951.00  0.00   DF2JP JO31JG         
1204   2  -27  -0.4 1940.35  0.00
1206  10  -18   0.0 1950.84  0.00   DF2JP JO31JG         

1214  10  -18  -0.1 1950.84  0.00   DF2JP JO31JG         
1218  10  -16   0.3 1951.00  0.00   DF2JP JO31JG         
1222  10  -17   0.2 1950.92  0.00   DF2JP JO31JG         
1226  10  -18   0.1 1950.92  0.00   DF2JP JO31JG  

1230  10  -16   0.0 1950.92  0.00   DF2JP JO31JG

 

One successful wav from 12:22 also uploaded to

http://df6nm.bplaced.net/wsjt/jt9-2_121104/

 

Will try to call you for another QSO.

 

73, Markus

 

From: Markus Vester

Sent: Sunday, November 04, 2012 12:31 PM

To: rsgb_lf_group@blacksheep.org

Subject: Re: LF: AW: DF2JP JT9-1 137.445 kHz

 

Switched the LF grabber back to the rooftop TX Marconi, which improved SNR by about 5 dB. Got a single decode at 11:18 but otherwise all empty lines :-(

 

1118 10 -18 -0.4 1951.07 0.00 DF2JP JO31JG

1120 2 -27 0.3 1924.55 0.00

1122 10 -16 -0.4 1951.10 0.00

 

73, Markus

 

PS The rain has stopped, and we're getting patchy sunshine.

 

From: Markus Vester

Sent: Sunday, November 04, 2012 11:39 AM

To: rsgb_lf_group@blacksheep.org

Subject: Re: LF: AW: DF2JP JT9-1 137.445 kHz

 

Joe,

 

it's raining here also now - what a "dog's weather" ;-)

 

My main antenna is currently still resonated on MF but I'm receiving you well on the auxiliary low-mounted "summer antenna" in the garden. Half-seriously thought that lower SNR might help to decode, but apparently not so:

 

1020 1 -28 -0.4 1927.09 0.00

1022 10 -20 -0.4 1951.03 0.00

1024 0 -31 -0.3 1951.76 0.00

1026 10 -21 -0.1 1951.65 0.00

1028 0 -30 -0.1 1923.24 0.00

1030 10 -20 -0.4 1951.81 0.00

 

Using WSJT-X v0.2 r2713, wav file from 10:26 uploaded to

http://df6nm.bplaced.net/wsjt/jt9-2_121104/121104_1026.wav

 

Best 73,

Markus

 

From: Joe

Sent: Sunday, November 04, 2012 10:43 AM

To: rsgb_lf_group@blacksheep.org

Subject: AW: LF: AW: DF2JP JT9-1 137.445 kHz

 

Good morning Markus, LF

 

Nice to hear that You had such a nice weather, when I was out with the dog, it was raining cats here?hi.hi

 

I´ve just started my daylight session on 136.000 + 1445Hz in JT9-2.

Reports are much appreciated.

 

Running 80 watts in to an Inverted-L (13m x 46m)

 

73 Joe

 

 

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Von: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org] Im Auftrag von Markus Vester
Gesendet: Samstag, 3. November 2012 18:05
An: rsgb_lf_group@blacksheep.org
Betreff: Re: LF: AW: DF2JP JT9-1 137.445 kHz

 

Hey Joe,

 

this afternoon the PC in the shack faithfully reported your WSPRm, while I was enjoying the autumn sunshine in the garden with our cat ;-)

 

When your JT9-1 came up again I attempted again for a while to decode it, but all I got between 16:37 and 16:43 were a few sync points on the right frequency (using r2813 at 135.5 kHz USB). 

 

Irgendwo is' da noch der Wurm drin...   

 

Best 73,

Markus (DF6NM)

 

From: Joe

Sent: Saturday, November 03, 2012 4:12 PM

To: rsgb_lf_group@blacksheep.org

Subject: LF: AW: DF2JP JT9-1 137.445 kHz

 

Hi Marcus, LF

 

I´m currently txing JT9-1 on 136.000 Dial + 1445 kHz.

Have to go out with the dog but leave the becon running.

 

73 Joe

DF2JP

 

 

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Von: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org] Im Auftrag von Markus Vester
Gesendet: Samstag, 3. November 2012 10:57
An: rsgb_lf_group@blacksheep.org
Betreff: LF: DF2JP JT9-1 137.445 kHz

 

9:51 decoded nicely,

9:53, 9:55 not decoded

 

73, Markus (DF6NM)

 

0950 1 -27 0.0 1958.60 0.00

0951 5 -24 -0.2 1944.96 0.00 DF2JP JO31JG

0952 2 -26 0.1 1959.61 0.00

0953 10 -21 -0.2 1944.69 0.00

0954 3 -26 -0.1 1958.60 0.00

0955 10 -20 -0.2 1945.38 0.00