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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