--- In FT817@y..., Michael Dirska <md@m...> wrote:
Hello Tom,
At Dayton I got an INRAD 500 Hz CW filter to tighten up the
passband
for PSK31 use. Here I am using the Menu #26 DIG=PSK31-U mode, so
the
filter is enabled with #38 FILTER=CW.
What I see happen is that when the filter is enabled with NAR, the
frequency jumps 30 Hz higher. I have checked and there is no
on/off
frequency shift in CW or sideband (with #38 set to SSB).
I ran into this problem also at the weekend - when I first used
PSK31 (coolest digital mode ever.. ;-)
Since these filters are passive devices, and since no offset is
seen
in SSB or CW, this seems to me to be a bug. With PSK31 bandwidths
being so narrow, it is a pretty serious flaw. Has anyone else seen
this problem? Or, by chance, is there a chance that this apparent
bug
is in fact an "unadvertised feature" (following the proud
tradition
of Windoze software)?
You're right.. The shift comes from the software. But if you set
"26 DIG MODE" to "USER U", the mysterious shift disappears. The
only thing with this is, that the passband shifts from
1000Hz to 1500Hz.. But I believe you can program that also in
this "user mode".
Hope this helps.
73 de Michael, DL1BFF
