[WriteLog] Sound Card Demodulation questions

[Ron Lodewyck]

Dave, et al,

I found your comments very interesting primarily because they also reflect
our experience at NN6NN located in central California.  This was our first
RTTY effort from W6XK's station and Chet's first exposure to RTTY ever.  We
used the latest version of Writelog on a 300Mhz PII HP notebook and used the
notebook sound card for demodulating.  We used FSK with the TS870 so we were
able to use the standard FSK position on the transceiver.  Most signals
lined up in the center of the passband with filter width usually set to the
minimum of 250 Hz, but we did have to play with the RIT a lot (even with the
AFC option box selected when running).  We used only one radio.  The antenna
is a Force 12 C4 at 70 feet on 10, 15 and 20M.

We managed 1093 Q's after dups removed and found Writelog to work very well
in general.  It also copied domestic stations, including pretty weak
stations, nearly perfectly once they were tuned in correctly.  However, on
the polar routes it would not copy many, maybe as high as 50%, of the
European signals even if they were quite strong - say S8 or S9.  We tried
retuning, varying the filter width, and moving the beam to a skewed path
(which turned out to be the best compromise), with little success.  We did
not experience this problem when  copying JA's, but we did have the same
problem on backscatter.

Writelog has an option "View Wideband decode" under the RTTY window File
menu.  We tried it without any noticeable improvement in copy, but others
have reported that it is helpful.

I doubt that there is much more a software TU can do, but we sure did miss a
bunch of Q's and especially Multipliers due to our inability to copy the
fluttery signals.

BTW, thanks for all the Q's -- 10, 15, 20 and 80M!  Hope to see you in the
next contest.

73,
Ron N6EE
aka NN6NN

----- Original Message -----
From: "Dave Hachadorian" <k6ll@juno.com>

> I saw K5ZD's comment that "If he could hear the signal, the sound
> card would print it." That was not quite my experience here. The
> print was generally quite good (1171 QSO's!), but there were times,
> especially on the Europeans, where it would just not print. Some
> of these signals were quite loud, but you could hear the flutter
> on them. It's a 3 hop polar path to EU from here. The soundcard
> also had a little trouble with backscatter stations from California.



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