Date: Sun, 18 Dec 2016 20:23:55 -0330 (NST)
From: jcraig@mun.ca
To: rsgb_lf_group@blacksheep.org
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Message-ID: <Pine.LNX.4.64.1612182011120.16449@plato.ucs.mun.ca>
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Subject: Re: LF: EBNAUT beacon on LF
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Hi Markus,

Thank-you for the reply.  Tonight there was tinkering with the pilot dds=20
and software with gratifying results.  The amplitude will be reduced for=20
our next trial.  It seemed rather strange that the SL FO required a=20
clearly audible signal.

The sample rate was  Calib12000=3D11999.76580086

The accuracy of the pilot will be checked tonight on your high res=20
grabber.  Thanks again for this service.

73
Joe

On Sun, 18 Dec 2016, Markus Vester wrote:

> Hi Joe,
>
>
> thanks again for the files - unfortunately no luck so far. The attached s=
pectrum shows a very strong pilot signal at an offset which drifted slightl=
y from 0.0990 to 0.0897 Hz during the night. But no decode from the 0610 fi=
le - perhaps 13 characters was asking a bit too much at the current state o=
f affairs.
>
>
> The problem with the strong pilot is that it apparently aliases back into=
 the EbNaut channel. Last time we saw a few spurious peaks and a relatively=
 low dB value for "carrier-derived" Eb/N0. I do not know exactly how much t=
he aliasing affects the decodability. It also appears that despite the gree=
n status indicator, the frequency offset detector did not really remove the=
 receiver offset anyway. So I would suggest to give up on that for the time=
 being. After reducing the pilot by about 40 dB it will still be visible in=
 the 0.4 mHz FFT bandwidth, enough to serve as an a posteriori frequency ma=
rker when processing the files.
>
>
> I did see mconfig.ini in your directory http://www.ucs.mun.ca/~jcraig/ebn=
aut but somehow couldn't download it. Could you just tell us the samplerate=
?
>
>
> All the best,
> Markus (DF6NM)
>
>
>
> -----Urspr=C3=BCngliche Mitteilung-----
> Von: jcraig <jcraig@mun.ca>
> An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
> Verschickt: So, 18 Dez 2016 9:31 pm
> Betreff: Re: LF: EBNAUT beacon on LF
>
>
> Hi Markus,
>
> The files are uploaded after an infuriating battle with the pc!
> A screen grab sl05.jpg is there too.
> Strangely, the pilot amplitude had to be increased to get
> the green OK rather than yellow warning in the Frq offset
> detetor. The ini file was also uploaded. rsNTP was running
> during the process.
>
> Good luck and have fun!
>
> Joe
>
> On Sun, 18 Dec 2016, Markus Vester wrote:
>
>> Hi Joe,
>>
>> that's great news - yes we are surely keen to look for our signals in yo=
ur recordings.
>>
>> Dom's and my 29 minute transmissions started on the hour, so the best fi=
les would be the ones centered near hh:15. Ric's transmission was somewhat =
shorter. From your list, I'd probably select the ones ending in xx:10, whic=
h are
>>
>> 12172210.txt,
>> 12172310.txt,
>> 12180010.txt,
>> 12180110.txt,
>> 12180210.txt,
>> 12180310.txt,
>> 12180410.txt,
>> 12180510.txt,
>> 12180610.txt.
>>
>> Did you still employ the DDS pilot injection to guide us to the right fr=
equency? Last time the pilot was more than 50 dB above the noise, which may=
 have reduced carrier-EbN0 readout and affected decoding. For future sessio=
ns, I'd recommend to reduce the pilot level by about 20 dB.
>>
>> We'd also need to know the result from your samplerate calibration (1200=
x.xx Hz). This was displayed during the calibration - if you hadn't noted i=
t at the time you can still read it from the audio correction table or from=
 mconfig.ini.
>>
>> Was the PC clock steered by NTP or some other means?
>>
>> Best 73,
>>
>> Markus
>>
>>
>>
>> -----Urspr=C3=BCngliche Mitteilung-----
>> Von: jcraig <jcraig@mun.ca>
>> An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
>> Verschickt: So, 18 Dez 2016 2:26 pm
>> Betreff: Re: LF: EBNAUT beacon on LF
>>
>>
>> Hi Domenico and Markus,
>>
>> Here is a list of EbNaut files. I can upload a few of them
>> if you would like. Let's hope SR and FO were properly engaged!
>> There is a compiled ebnaut on this unix box that I should be using too.
>>
>> 73
>> Joe VO1NA
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