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Re: WOLF: 135975 Hz, 10 b/s again

To: <[email protected]>
Subject: Re: WOLF: 135975 Hz, 10 b/s again
From: "Markus Vester" <[email protected]>
Date: Sat, 28 Jan 2012 08:45:00 +0100
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The little Wolf signal was on air from 23:05 to 07:15 this morning, with ERP down by a dB or so because of snowfall. The phase monitor showed a continuous steady frequency without a single glitch.
 
Thanks again to all who have kept an eye open for me. At least we know if we didn't succeed tonight, it was really due to suboptimal propagation and/or insufficient ERP from my side.
 
Best 73, and have a nice weekend
 
Markus (DF6NM)

Sent: Saturday, January 28, 2012 12:01 AM
Subject: Re: WOLF: 135975 Hz, 10 b/s again

Hi Andy, LF,
 
actually there is no carrier line in the WOLF spectrum, it's BPSK with a pseudorandom spreading code. In a spectrogram it resembles a 10 Hz wide noise band, which will be pretty much undetectable at any DX range. Actually a kind of spread spectrum mode, not unlike the GPS modulation (pssst ;-).
 
I think I have proven (and resolved) my soundcard phase-glitch problem. The attached trace shows a local audio test, with a WOLF signal generated on 1475 Hz. It is doubled in SpecLab's AM demodulator to regenereate a carrier at twice the frequency, which is phase compared to an hardware generated Rb-derived reference carrier. I have employed SpecLab's RDF mode to display phase as colour (retarding R-B-G-R). The first half shows the result from WOLF-Gui running on my "Grabber Notebook", which has a number of programs running. Besides the gradual phase roll due too a very minor frequency offset, there are jumps every few minutes. This is a bit nasty, as Wolf will still decode such a signal when it is strong, but not be able to go to its full sensitivity by using long coherent integration. The right half after 21:40 shows the practically perfect output from the Atom Netbook, the one which I have also used during several VLF transmissions. 
 
So, maybe it's worth another try. Will put the "good" WOLF signal on air a few minutes after 23 UT, QRG 135975 Hz, 10 b/s.
 
Best 73,
Markus (DF6NM) 
 
Sent: Friday, January 27, 2012 7:54 PM
Subject: Re: WOLF: 135975 Hz, 10 b/s

My report is the same... no decodes... I wish as an after thought that I had ran SpecLab also, to look for the carrier...
maybe next time
 
73:
 
Andy - KU4XR - EM75xr - Friendsville, TN. USA
Coordinates: N: 35º 43' 54" - W: 84º 3' 16"
http://lwca.org/grabbers/ku4xr/
http://www.myspace.com/beaconxr
http://ku4xr.webs.com
http://lwca.org/community/YaBB.pl

From: "[email protected]" <[email protected]>
To: [email protected]
Sent: Friday, January 27, 2012 8:41 AM
Subject: Re: WOLF: 135975 Hz, 10 b/s

Markus
 
No joy here either.
 
Jay W1VD  WD2XNS  WE2XGR/2
----- Original Message -----
Sent: Friday, January 27, 2012 7:50 AM
Subject: Re: WOLF: 135975 Hz, 10 b/s

Many thanks Andy, John and Dex for looking out for my WOLF signal. The TX was running without interruption from 23 to 7 UT, PEP about 0.5 W ERP. 
 
One thing I still don't trust is the continuity of the soundcard output. I guess the glitches which occasionally appear in QRSS dashes might corrupt the long-term phase-coherence which is required for deep WOLF decoding. Will have to look into that before the next attempt.
 
Best 73,
Markus (DF6NM)
 
 
Sent: Friday, January 27, 2012 12:53 PM
Subject: Re: WOLF: 135975 Hz, 10 b/s

Markus,

No luck. Not a quiet night, and TA prop does not seem to have recovered.

John, W1TAG

On 1/26/2012 10:02 PM, John Andrews wrote:
> Markus,
>
> Nothing seen as of 0300, other than the usual infinite number of monkeys
> typing away. Will let it run overnight.
>
> John, W1TAG
>
> On 1/26/2012 5:39 PM, Markus Vester wrote:
>> WOLF ... good idea!
>> My TX antenna has been pushed up again tonight, and I intend to howl for
>> a couple of hours, starting 23:00 UT at 10 b/s speed.
>> As CFH is still sitting smack in the middle of the band, I'll move close
>> to the lower edge, squeezing into a narrow HGA-sidebands gap on *135975
>> Hz* (that is unless you may have other suggestions).
>> Best 73,
>> Markus (DF6NM)
>>
>> *From:* John Andrews <mailto:[email protected]>
>> *Sent:* Wednesday, January 25, 2012 3:30 AM
>> *To:* [email protected] <mailto:[email protected]>
>> *Subject:* Re: LF: WOLF DATA MODE S/N FIG ?
>>
>> Graham,
>>
>> There is no single s/n figure or specified BW in which to measure it.
>> WOLF works by building copy up over a period of time, and assuming good
>> frequency/phase stability, a half hour or more is practical.
>>
>> The data rate is fairly fast, 10 b/s, with a 960 bit message, so that a
>> complete frame of data is sent in 96 seconds. You get three quick
>> reports in the first 96 seconds, and then decodes every 96 seconds
>> after. Each message is 15 characters, with no rules about callsign
>> format.
>>
>> Tests done some years ago show it roughly equivalent to QRSS60 in terms
>> of signal level. It does give some clues as to whether a signal has been
>> locked-in, and has the possibility of partial copy, unlike some "all or
>> nothing" modes. Fifteen characters in a half-hour is of course much
>> faster than QRSS60 would permit. 2-way QSO's are fairly easy with some
>> advance agreement on what to do with the 15 characters.
>>
>> The downsides are the need for a linear transmitter system (as this is
>> PSK), receiver/transmitter stability and frequency accuracy. It works at
>> 600 meters, but is fairly useless at 160 meters and up.
>>
>> The newest version is by DL4YHF, and may be found at:
>> http://www.qsl.net/d/dl4yhf//wolf/ .
>>
>> Note that this version has 5 b/s and 20 b/s variations. Testing has
>> shown that the program tends to provide copy in the same amount of time,
>> so there's no overriding advantage to either.
>>
>> John, W1TAG
>>
>> On 1/24/2012 7:27 PM, Graham wrote:
>> > WOLF DATA MODE S/N FIG ?
>> > Long time since I used wolf , anyone have the
>> > expected decode min s/n level ?
>> > and now what s/n was ref to , as changes
>> > may of taken place over time
>> > Tnx -G.
>> >
>> >
>> >
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>>
>>
>>
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>
>
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