[WriteLog] SO2R with RITTY and MMTTY

[George Johnson]

Jim,
Yes, I think adjustment of audio levels significantly influences the
performance of sound card decoders.  I use RITTY but am experimenting
with MMTTY and other sound card systems.  I still prefer RITTY under
most contest and DX conditions.

I have used both the headphone audio output from my Icom radio(s) as
well as the fixed level output from the rear accessory connection.  I
could not get sufficient output from the fixed level into the line-in
ports of a couple PC audio boards.  I am presently using a simple audio
amp to boost the level by about a factor of 7 to go into the sound card
line-in port.  But there was adequate audio from a Y-connection on my
headphone line.  I have also used the sound card mic port but I get some
apparent distortion with some sound cards.

I set up the levels using the DOS configuration and graphic display in
RITTY.  I then use that group of settings for the ritty.ini file
employed with WL contesting.  It seems to work fine...  I end up with
two versions of an *.ini file;  one for contesting and one for general
use.

FWIW I just built up the sound card interface described in March QST.
The author, AA4PB, did an excellent circuit design job with line
filtering and isolation.  I will also use the "bazooka" shielding
technique for the lines between the computer and interface.  I am
missing some audio jacks so I have not tested it electrically yet.  This
circuit will be used in our Field Day operations.  It was designed for
Icom accessory socket interface but can easily be adapted to any radio.

73 and GL,
George .. W1ZT

----- Original Message -----
From: "Jim Smith" <jimsmith@shaw.ca>
To: <writelog@contesting.com>
Sent: Tuesday, April 02, 2002 2:19 AM
Subject: Re: [WriteLog] SO2R with RITTY and MMTTY


> Thanks for the comments.  What I think I would like to be able to
change
> during a contest is the audio level into RITTY as I don't think it is
> working as well on weak signals as it can.
>
> I guess my question is, "Will changing the audio level into RITTY
affect
> weak signal performance?"
>
> Eventually I'm going to have all the audio I/O running through a small
> patch bay with individual level controls on all the lines that need
it.
>  However, that's down the road a bit.
>
> Mike wrote:
>
> >Hello Jim,
> >
> >RITTY works great with WL.  When using RITTY with WL, you can still
select
> >the filters from the RITTY window along with switching between
reverse
> >receiver and/or transmit and change the flywheel capability.
> >
> >Not sure what other parameters you would want to adjust in a contest.
You
> >should set-up several paramters prior to using RITTY with WL.  For
example,
> >the filter size, center freq., shift, etc.
> >
> > 73,
> > Mike, K4GMH
> >
> >At 02:07 AM 3/28/02 -0800, Jim Smith wrote:
> >
> >>I also use RITTY with WL.  Sometimes it seems to work well on weaker
> >>signals and sometimes it doesn't.  (No multipath or polar flutter.)
I
> >>have this feeling that if the audio level isn't right RITTY doesn't
work
> >>as well as it can.  I have tried running it by itself in a DOS box
and,
> >>with audio levels adjusted appropriately using the settings
available in
> >>RITTY it was great.  Under WL the ability to set RITTY parameters
> >>doesn't seem to be there and the performance is far from great.
i.e. if
> >>the relatively weak signal were cw instead of RTTY it would be solid
> >>copy as opposed to mostly garbage.
> >>
> >>Do you RITTY users get good weak signal performance from RITTY when
used
> >>with WL?
> >>
> >>Am I missing something?
> >>
> >>73 de Jim Smith    VE7FO
> >>
> >>
> >>John Cashen wrote:
> >>
> >>>During my shortened BARTG effort(I even missed XR0X, although I did
> >>>hear his pileup) I took a little time to compare RITTY with MMTTY.
> >>>
> >>
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