[Lowfer] Help with WOLF parameters

[Richard Goodman]

John,

   Thanks for the infomation on the WOLF receive parameters. I would also be
greatly interested in trying for a weaker signal. This mode has really
captured my interest. Within 3 minutes I was able to reliably capture your
signal running at a power of 1 watt. I was also watching you on ARGO ... if
that "XNS PW 1 WATT" phrase had been sent via QRSS30 it would have taken
over 45 minutes. I am curious in reference to what a QRSS signal would look
like from your transmitter running the same power level as a corresponding
WOLF transmission. Has anyone ran an experiment like that to your knowledge?

73
Dick, WA3USG


-----Original Message-----
From: lowfer-bounces at mailman.qth.net
[mailto:lowfer-bounces at mailman.qth.net]On Behalf Of John Andrews
Sent: Monday, March 12, 2007 8:13 AM
To: Discussion of the Lowfer (US, European, & UK) and MedFer bands
Subject: Re: [Lowfer] Help with WOLF parameters


Dick,

Nice to see that you contributed to the 70 million that the movie took
in over the weekend. Looks like it may make back its effects budget.

t: correct, time in seconds.

f: Yes, offset in Hz from the BFO pitch, 800 Hz in this case. If you see
this value slowly shift while the program is "locked-on", then you may
have receiver frequency drift. Or the guy sending may be drifting...not
the case with either Jay or myself!

pm: This will give you an idea of the strength of the signal. I believe
it works on the data in the "reference channel," which is the
predetermined 480 bit message interleaved with the message being sent.
The number will never decrease, but will grow as copy is accumulated.
The things to watch for are the rate of increase, and the amount per
line. Steady growth is a good thing. Increases of 4000 or more per step
actually indicates overload, and you could back off on the RF gain.

jm: These are bit-timing values that indicate the framing of the decoded
signal. This runs from 0 to 959. The number itself is meaningless, but
you can learn a lot from watching the overall output. Several lines of
the same value may indicate that you have locked onto a signal. If you
are getting correct text copy, but the "jm" value is slowly changing,
you probably have an error in specifying your sound card's sampling
rate. Note: you can't tweak the actual sampling rate of the sound card;
you can only report the actual value to WOLF so it will compensate for
it. The copy of my signal from last night shows stable "jm" values, so
your card may be close to the default 8000 Hz value. Some are...some
aren't, and price may not be the determining factor.

q: These are two signal to noise readings. The first one is for the
reference channel, the second one for the data channel. Higher numbers
(more positive) represent better signal to noise ratios. If you see "q"
values of -3 or greater, expect to start seeing clear copy.

Based on the copy you sent from last night, you don't have much tweaking
to do. You could learn more by playing with a weak signal -- my 500
watts is pretty strong at your qth. Maybe Jay or I could provide a
weaker signal some night. He copied me down to 5 milliwatts yesterday
afternoon, but couldn't quite make it with 500 microwatts. We'll let you
know.

John A.

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