[Moon] EA9LZ 6cm

André F1PYR andre_f1pyr at yahoo.fr
Tue Oct 10 17:34:26 CEST 2017


Thanks Charlie , I forgot to precise , I use a Digibox 2 between TS2000 and PC
73 Andre

      De : G3WDG via Moon <moon at moonbounce.info>
 À : John Lambo <pa7jb at ziggo.nl> 
Cc : moon at moonbounce.info
 Envoyé le : Mardi 10 octobre 2017 16h59
 Objet : Re: [Moon] EA9LZ 6cm
   
Hi John

There are really no special tricks to using QRA64 compared to say JT4, or
JT65.

You don't have to use the CAT rig frequency control capability initially,
but just request your sked partner to do full Doppler control, whereby all
the Doppler compensation is taken care of my your partner and you just TX
and RX on one frequency. They will offset their TX and RX frequencies for
your grid.

Otherwise it is quite straightforward, and the basics are explained here:

http://www.physics.princeton.edu/pulsar/K1JT/wsjtx-doc/wsjtx-main-1.7.1-devel.html#_qra64

Further tips are given in the link at the end of this section.

It is a good idea to play with some recorded files off-air, that can be
downloaded from Joe's site, as described in the User Guide. I can provide
more examples if needed, including some interesting files from last
night's 6cm activity  that contain more than one signal.

73

Charlie


 > Hello all lunatics.
> Maybe  a idea Charlie or someone else that you can put somethings on
> Youtube or a other cannel??
> How you have the setting or tricks to use QRA64 beter??
> I am what we say here in PA0 a ( digibeet )
> So i am not that good with computers ;-)
> As some know i did have problems here that i did not work EA9LZ on any
> band.
> But the next expidition will also use QRA64 on 6 and 3cm.
> For me it is not so easy to work with it.
> In CW you only need  key ;-)
> Again i like to say a big thank you to Zdenek that he was active on so
> many bands and this all with only one person !!!!!
>
>
> 73  John  PA7JB
>
>
> Op 10-10-2017 om 12:46 schreef G3WDG via Moon:
>> Hi John
>>
>> There are a number of factors that could have been at play here.
>>
>> VK7MO and I did an extensive comparison of QRA64 and JT4F some time ago,
>> and published the results in Dubus 3/17.  These involved the use of both
>> simulation and lots of on-air testing (on 3cm).  The conclusions showed
>> a
>> clear advantage for QRA64, for libration spreading values of up to about
>> 200Hz. Yesterday on 6cm we were well below this spreading.
>>
>> One of the things we learnt from the study was the need to look at large
>> numbers of test files (thousands) to reduce effects of statistical
>> variations - small sample sizes can easily give misleading results.
>>
>> The performance of QRA64 is also dependent to some extent on the
>> settings
>> used.  There is a link in the User Guide at the end of Section 8.4 that
>> describes some of these factors.  The linked document also describes how
>> to set up the waterfall to be more like WSJT10's, which makes seeing the
>> tones somewhat easier than with the default waterfall settings in
>> WSJT-X,
>> but this of course does not affect decoding performance.
>>
>> A common reason for failure to decode is when you are tuned so that the
>> lowest (leftmost) tone of the QRA64 signal falls outside the range of
>> Ftol
>> you have selected. Choosing a low value for Ftol, while this can
>> sometimes
>> help decode very weak signals, does increase the requirement for tuning
>> precision.  You commented on the logger that you could hear the tones
>> audibly.  In this case QRA64 in our experience has no trouble whatsoever
>> in decoding.
>>
>> When comparing the performance of QRA64 and JT4 when no prior knowledge
>> of
>> callsigns is available, QRA64 has an even larger advantage.  Hence it
>> really comes into its own for random operation.  With JT4 running with
>> correlation decoding (Deep Search) and a small sample size the
>> difference
>> may not be so apparent.
>>
>> By 'above the line' on WSJT10, are you referring to the difference
>> between
>> a single line decode and a decode obtained by averaging?  QRA64 does not
>> have an averaging capability, at present.
>>
>> When the JT4 decoder needs to use correlation to obtain a decode, the
>> decoded text includes a quality factor.  Smaller numbers mean that the
>> decoder had less confidence that the decode was a correct one, and if
>> you
>> see a ? in the decode then it is normal practice to wait for another
>> decode to see if it is the same, after which you can be more confident
>> that the decode was a correct one.  With QRA64 it is our 100% experience
>> that you can rely on a decode being correct.
>>
>> 73
>>
>> Charlie
>>
>>
>>
>>> Hi Zdenek, well done! Great to finally get to you on 6cm last night for
>>> a
>>> second band.
>>> Only sorry I screwed up the day for 13cm as we would have made it 3
>>> bands.
>>>
>>> Your decision to switch to JT4F  was inspirational!
>>>
>>> I was running both WSJT10 (RX) and WSJT-X (RX and TX) in parallel
>>> during
>>> the JT4F QSO and at no time did I either of the softwares fail to
>>> decode
>>> you, whereas with QRA64D I got just 2 decodes in the hour or so of
>>> trying!
>>> That said you did seem stronger when you were running JT4F. Maybe our
>>> minor
>>> tracking errors just got "in synch" for the JT4F QSO.
>>>
>>> Having slept on it, I wondered if it might have been the deep search in
>>> JT4G, but all the decodes were "above the line" on the WSJT10 screen. I
>>> don't know enough about Joe's excellent software to know if that really
>>> means it was a pure decode without deep search? Maybe one of our
>>> digimode
>>> experts may be able to tell me or have a view on their experiences
>>> comparing the two modes at really low levels? I was expecting QRA64 to
>>> be
>>> much better.
>>>
>>> 73 John
>>>
>>>
>>> On 10 October 2017 at 08:34, Zdenek SAMEK-OK1DFC via Moon <
>>> moon at moonbounce.info> wrote:
>>>
>>>> Hi EME gang, "game is over" , last evening I have loged 20 QSOs. Looks
>>>> that
>>>> everybody who was interesting have EA9, has EA9. Now will wrap up all
>>>> the
>>>> stuff and tomorrow morning I have ferry back to Spain. Then only drive
>>>> 3000
>>>> km and looking forward to see my sweet home.  Thanks to all of you for
>>>> QSOs,
>>>> many very nice emails and looking forward to meet you again via Moon.
>>>> 73!
>>>>
>>>> --
>>>> Zdenek - OK1DFC
>>>> www.ok1dfc.com
>>>> QRV EME 144 MHz - 10 GHz
>>>> WAC 432 - 1296 - 2320 MHz
>>>> WAZ #9 - WAS 432 #29
>>>> DXCC 432 - 1296 MHz
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