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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-G-B-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:
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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