"RTTY signal is not centered in the pass band. Both rigs
are using a
filter width of 350 Hz - the PROII set with DSP and the 706
using an
FL-232."
If I understand correctly what you are saying, you are using
HIGH TONES and a filter width in the PRO of 350 Hz. You do
not say what the I.F. SHIFT is. I have not been able to set
a pass band width lower than about 750 Hz, keeping the
signal within the pass band with the PRO using high tones.
For that reason, I use LOW TONES. How do you do that?
Duane Budd
w5ben@arrl.net
Johnson City, TN
-----Original Message-----
From: rtty-admin@contesting.com
[mailto:rtty-admin@contesting.com]On
Behalf Of WA9ALS - John
Sent: Friday, February 15, 2002 5:39 PM
To: Writelog@contesting.com; rtty@contesting.com
Subject: [RTTY] MMTTY x 2
Last night I thought I had MMTTY going in 2 instances using
the
computer's integrated sound and a Soundblaster card.
However, the audio
on one rig appeared to be out of the passband. I've
experimented some
more now with MMTTYx2. To show this graphically, I've made
the
following screenshots:
http://wa9als.mystarband.net/rig1.gif
http://wa9als.mystarband.net/rig2.gif
Sorry for the large screenshots, but I have 2 monitors and I
wanted all
the settings to be readdable. BPF is not set in one
instance of MMTTY,
but that's not the problem.
If you look at the first one above, rig1, you see the PROII
transmitting
and the 706 receiving on the same frequency. However, you
see that the
RTTY signal is not centered in the passband. Both rigs are
using a
filter width of 350 Hz - the PROII set with DSP and the 706
using an
FL-232.
Conversely, the second shot above, rig2, shows the 706
transmitting, and
the received signal in the PROII's spectrum (on the left) is
more like
it should be.
Several have suggested that MMTTY was not set for 2125 and
170, but
that's not the problem. Neither is it a problem with the
settings on
the 706. By mixing and matching this afternoon, I've
determined that
the problem only is apparent if the audio is passing through
the
computer's INTEGRATED SOUND system. (I have integrated
sound for one
"soundcard" and a Soundblaster Live Value card as the
other.)
If I put the PROII's audio through the INTEGRATED SOUND
instead of the
Soundblaster, I have the same problem. Thus it's something
about the
integrated sound system that's throwing the audio out of
where MMTTY is
looking. WHAT WOULD DO THAT?? I can't find any settings of
the
integrated sound that have any apparent pertinence or
effect. I could
get another Soundblaster card, but it seems like the
integrated sound
should work OK (AC'97 codec). Any ideas about this weird
freq shift
only seen when using the integrated sound?
THANKS!
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