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).
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)?
73 de Tom, W3IWI (private replies to w3iwi @ amsat.org)
