Date: Wed, 11 Nov 2015 21:43:14 -0330 (NST)
From: jcraig@mun.ca
To: rsgb_lf_group@blacksheep.org
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Subject: Re: LF: VO1NA frequency
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:-)

73 Alan!
Joe

On Wed, 11 Nov 2015, Alan Melia wrote:

> Hi Joe plaese be sending the cats bank account numbre and sort cod e so w=
e=20
> may pay his inheritance  :-))
>
> Alan
> G3NYK
>
> ----- Original Message ----- From: <jcraig@mun.ca>
> To: <rsgb_lf_group@blacksheep.org>
> Sent: Wednesday, November 11, 2015 11:35 PM
> Subject: Re: LF: VO1NA frequency
>
>
> Hi Markus (and thank-you to Chris, Urlich, Iban and Graham for
> reports/relays)
>
> Your critiques of my signals are very thorough and masterful.  I am
> most grateful.  There is a concensus amongst you, Domenico and Stefan
> that I've gone off frequency again, at times more than 1 mHz!
> Hopefully this will be corrected soon. I'll post your nice plots
> on the web if you don't mind.
>
> In the mean time, I ran Paul's ebbaut.c on the MUN unix box and
> an old Model B raspi. It compiled flawlessly.  I had to put in
> arguments for -S and -r which I chose at random, my callsign and
> pussycat's name and was rewarded with a long list of 0's and 1's.
>
> So if I send a long carrier with a phase inversion every time a 1
> is encountered, it will be a valid ebnaut transmission? What is
> the duration of the elements and what arguments should I pass to
> ebnaut.c?  Also, would a transformer + DPDT relay work?  A ring
> mixer might not take kindly to a 12V squarewave.
>
> Please excuse my naivety!  Also, XYL is wondering why you want the
> other details of the cat.  She was my ground crew today while I was
> atop the tower so I must be diplomatic!
>
> MNI TNX
> Joe VO1NA
>
> On Wed, 11 Nov 2015, Markus Vester wrote:
>
>> Joe,
>> =C2
>> more of the same from last night, this time with=C2 frequency and level=
=20
>> plots. Again we see some frequency variation of similar size as yesterda=
y.=20
>> It is not clear how much of that is due to propagation,=C2 I only think =
that=20
>> the=C2 rise=C2 near the end is due to Doppler=C2 from the=C2 descent of =
the=20
>> ionosphere at sunrise.=C2 Russian=C2 Loran lines on 137475 and 137482.5 =
seemed=20
>> to have less overnight variation (~ 0.1 mHz), but then of course the=20
>> intra-European path from Slonim is very different from yours.=C2
>> =C2
>> Regarding EbNaut carrier analysis:=C2 for some reason (lack of coffee?),=
 I=20
>> only saw Domenico's earlier mail after I had=C2 sent mine, so please exc=
use=20
>> me for basically having described=C2 the same procedure again.=C2 Anyway=
 it's=20
>> good that we=C2 both=C2 arrived at the same conclusion:=C2 If Joe starte=
d=20
>> sending=C2 EbNaut PSK with his=C2 oscillator as=C2 it is now, we would v=
ery=20
>> likely be able to decode it here.=C2
>> =C2
>> Joe so all you need now is a diode ring-mixer for PSK modulation and Pau=
l's=20
>> ebnaut-tx program.=C2 Symbol=C2 timing=C2 will=C2 be derived from=C2 the=
 PC clock,=C2=20
>> so with NTP=C2 available there's no need to involve GPS at all. If Paul=
=20
>> brought his LF receiver back to life, he could probably copy you even=C2=
 if=20
>> you reduced=C2 TX power to 0.1 Deccas.
>> =C2
>> How many cats do you have? We want to know=C2 names, colours, sex and ag=
e for=20
>> all of them ;-)
>> =C2
>> All the best,
>> Markus (DF6NM)
>> =C2
>> =C2
>> PS. SpecLab question: Wolf is there a way to extract peak frequencies fr=
om=20
>> past spectrogram lines (semi-)automatically, without having to manually=
=C2=20
>> move=C2 and read the mouse cursor over each point, e.g. something like a=
=20
>> peak_f(f1,f2, time) interpreter function?
>>=20
>> =C2
>> -----Urspr=C3=BCngliche Mitteilung-----
>> Von: Markus Vester &lt;markusvester@aol.com&gt;
>> An: rsgb_lf_group &lt;rsgb_lf_group@blacksheep.org&gt;
>> Verschickt: Mi, 11 Nov 2015 1:24 am
>> Betreff: LF: VO1NA frequency
>> =C2       Hi Joe,
>> =C2
>> the attached plot shows the  frequency=C2 stability of=C2 your=C2 opds t=
race=20
>> received last  night=C2 http://df6nm.bplaced.net/LF/opds32_151110_0736.p=
ng=C2 .=20
>> Each data point is the interpolated peak of a  single 438 uHz FFT (i.e. =
38=20
>> minute window). The average frequency seems to be  0.7 mHz below=C2 nomi=
nal,=20
>> and there are small temporal variations=C2 up  to=C2 0.5 mHz in either=
=20
>> direction.=C2 Though some of that=C2 is  probably=C2 attributable=C2 to =
noise and=20
>> propagation, I believe that there  is also a bit of inherent instability=
=20
>> in=C2 the frequency  source.=C2 Actually a few parts per billion=C2 is q=
uite good=20
>> for a free  running=C2 OCXO (assuming the "D" stands for "double oven" a=
nd=20
>> not "discipled"), and that the calibration was done over a 10  MHz=C2 HF=
=20
>> link.
>> =C2
>> Is this good enough for EbNaut? During the  experiments with IZ7SLZ we=
=20
>> found that for full sensitivity the phase variation  over the EbNaut=C2=
=20
>> sequence duration should not be much more than 90=C2=B0. Thus  for a hal=
f-hour=20
>> message the frequency should be ideally constant and known to  about 0.1=
4=20
>> mHz. If there is more variation=C2 we=C2 often=C2 can still  get=C2 deco=
des, but we=20
>> will have to find the best frequency offset by trial  and error, which c=
an=20
>> be cumbersome if the signal is weak.
>> =C2
>> I also fed opds data files from your Sat/Sun  transmissions to the EbNau=
t=C2=20
>> decoder. The idea was to see if=C2 your Opera  transmissions would actua=
lly=20
>> produce=C2 the all-asterisk=C2 decode which is  expected for a non-PSK-k=
eyed=20
>> straight carrier, and to observe the symbol phase  evolution over the 38=
=20
>> minute duration.=C2 Starting midnight UT, one decode was attempted every=
 30=20
>> minutes,  using a setting for 464 raw symbols (4 characters)=C2 and 5 se=
conds=20
>> per  symbol. A=C2 frequency offset of -0.6 mHz was=C2 selected=C2 to obt=
ain  flat=20
>> phase during the first decodes, and=C2 that offset=C2 was=C2 kept for  a=
ll later=20
>> attempts. Despite the Opera gaps  which=C2 degrade or drop half of the=
=20
>> available symbols,=C2 12 out of 13  decode attempts=C2 produced the  cor=
rect=C2=20
>> "****" message,=C2 e.g. http://df6nm.bplaced.net/LF/r0317.png . However =
at=20
>> times the frequency drift was quite visible=C2 on the=C2 phase plot,=C2 =
e.g. in=20
>> http://df6nm.bplaced.net/LF/s0317.png=C2 (flat  phase around 3:17) versu=
s=20
>> http://df6nm.bplaced.net/LF/s0347.png=C2 (upward  phase slope around 3:4=
7).=C2
>> =C2
>> Scaling down to VLF, deviations from the same  oscillator will be 16x=20
>> smaller (~30 uHz at 8.3 kHz). This will be probably good  enough even fo=
r=C2=20
>> narrow FFT bins, corresponding to several hours coherent  carrier=20
>> integration or slow EbNaut decodes.
>> =C2
>> All the best,
>> Markus (DF6NM)
>>=20
>>
>>  From: jcraig@mun.ca
>> Sent: Saturday, November 07, 2015 3:45 PM
>> To: rsgb_lf_group@blacksheep.org
>> Subject: Re: LF: VO1NA opds-32
>>=20
>>=20
>>=20
>>=20
>> LF Group,
>>=20
>> Again, thanks to SV8RV DF2JP PA7EY and DF6NM for  the reports.
>>=20
>> In my last post I reported the drift was constrained to  within 1 Hz.
>> This should be 1 mHz.=C2 Thanks Markus for your assurances  that this
>> should be adequate for EbNaut which I hope to use to send send our
>> cat's name on LF.=C2 The little curls appear often on the QRSS traces  o=
n
>> your high res spectra.=C2 Doppler variations were removed from the 10  M=
Hz
>> WWV signals with harmonic regression when the DOCXO was calibrated
>> so  this effect is seen on LF but not as strongly.
>>=20
>> After=C2 reading about  EbNaut on Paul Nicholson's pages it seems I have
>> much catching up  ahead.=C2 Fasinating stuff!
>>=20
>> Can the EbNaut phase inversions be done  without an absolute time
>> reference?=C2 I'm cheap and lazy so hoping GPS  will not be needed.
>>=20
>> The Opera will be doing an encore tonight and if the  wind stays low
>> a tower climbing expedition is planned for the  afternoon.
>>=20
>> 73
>> Joe VO1NA
>>=20
>>=20
>> On Sat, 7 Nov 2015, Markus Vester  wrote:
>>=20
>> &gt; Hi Joe, LF,
>> &gt;
>> &gt; during the last couple of nights,  opds detected all of your=20
>> transmissions between about 22=C2 and 7:30  UT.
>> &gt;
>> &gt; Attached is a zoomed 40 mHz section from my opds-32  spectrogram,=
=20
>> showing your central coherent carrier which contains half of the=20
>> transmitted average power. It seems to be about 0.5 mHz below 137477 Hz=
=20
>> (possibly due to a calibration error in my receiver). The 2.7 mHz spaced=
=20
>> sidelines during the early part (bottom) were caused by 6-minute-periodi=
c=20
>> interruptions from my own MF WSPR transmissions. However the little curl=
s=20
>> near  the carrier can presumably be attributed to Doppler-shifted multip=
ath=20
>> components. The carrier was still weakly visible for another hour after =
the=20
>> last  detection.
>> &gt;
>> &gt; Comparing the looks of the carrier to earlier IZ7SLZ  transmissions=
,=20
>> the stability of the signal and the path seems quite sufficient  for=20
>> half-hour EbNaut PSK transmissions. Unfortunately I missed the opportuni=
ty=20
>> to save the raw data and analyze phase evolution using the EbNaut decode=
r=20
>> itself  - will try that next time.
>> &gt;
>> &gt; All the best,
>> &gt; Markus  (DF6NM)
>> &gt;
>> &gt;
>> &gt;
>> &gt;
>> &gt; From: jcraig@mun.ca
>> &gt; Sent: Saturday, November  07, 2015 12:03 AM
>> &gt; To: rsgb_lf_group@blacksheep.org
>> &gt;  Subject: Re: LF: last night opera opds detection in  km07ks
>> &gt;
>> &gt;
>> &gt; LF Group,
>> &gt;
>> &gt;
>> &gt; I am grateful  to Joe DF2JP for his captures QRSS and Opera
>> &gt; Dionysious SV8RV for his OP  decodes to Domenico IZ7SLZ
>> &gt; for his OPDS decodes, and thanks to DF6NM for  opds!
>> &gt;
>> &gt; I do not know if my DOCXO is stable enough for  EbNaut.
>> &gt; It was set a couple of years ago and has not drifted more  than
>> &gt; 1 Hz since then.=C2 It seems the phase decoherence has  stopped
>> &gt; haunting me.
>> &gt;
>> &gt; I am hoping to replace the halyard  for the other 100m wire soon.
>> &gt;
>> &gt; OP32 again tonight as send this  email.
>> &gt;
>> &gt; 73
>> &gt; Joe
>> &gt;
>> &gt;
>>=20
>>=20
>>=20
>
>
>
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