Hi Markus,
Thank-you for the reply. Tonight there was tinkering with the pilot dds
and software with gratifying results. The amplitude will be reduced for
our next trial. It seemed rather strange that the SL FO required a
clearly audible signal.
The sample rate was Calib12000=11999.76580086
The accuracy of the pilot will be checked tonight on your high res
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
spectrum shows a very strong pilot signal at an offset which drifted slightly
from 0.0990 to 0.0897 Hz during the night. But no decode from the 0610 file -
perhaps 13 characters was asking a bit too much at the current state of 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 the aliasing affects
the decodability. It also appears that despite the green 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
marker when processing the files.
I did see mconfig.ini in your directory http://www.ucs.mun.ca/~jcraig/ebnaut
but somehow couldn't download it. Could you just tell us the samplerate?
All the best,
Markus (DF6NM)
-----Ursprüngliche Mitteilung-----
Von: jcraig <[email protected]>
An: rsgb_lf_group <[email protected]>
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 your
recordings.
Dom's and my 29 minute transmissions started on the hour, so the best files
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, which 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
frequency? Last time the pilot was more than 50 dB above the noise, which may
have reduced carrier-EbN0 readout and affected decoding. For future sessions,
I'd recommend to reduce the pilot level by about 20 dB.
We'd also need to know the result from your samplerate calibration (1200x.xx
Hz). This was displayed during the calibration - if you hadn't noted it 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
-----Ursprüngliche Mitteilung-----
Von: jcraig <[email protected]>
An: rsgb_lf_group <[email protected]>
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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