Hello Rick, I try to use "channelized" freqs for Olivia only on 20 meters and when the band is Olivia-crowded....otherwise I tune to the freq of a station calling and leave it at that. Often where Olivia goes so do the other digi modes, freq-wise. Be it packet, rtty, mfsk, DominoEx, Throb or the like I either pick a clear frequency to call or tune to a calling station. If band segments other than part of 20 meters ever have significant Olivia-only activity I might change my habits; but even now there is no real "Olivia exclusive" portion of 20. Can see the intent of spacing stations so as to not qrm others yet allow for maximum stations-per-band slice, but until Olivia becomes the only mode used in a certain spectrum (never happen) this seems impractical.
Like you, I try to center my AF frequency at about 1500 Hz as that is the center of my filter's passband unless I intentionally offset it.. 73 Bill N9DSJ --- In [email protected], KV9U <[EMAIL PROTECTED]> wrote: > > I know Bonnie frequently takes a contrarian view of things, but do most > of you move your audio tones with Olivia so the bottom is at a > particular poin, much less, 516 Hz? > > Multipsk typically centers modes on 1000 Hz. I have to tweak it to > center on 1500 Hz since that is what is required by my ICOM 756 Pro 2 > for optimum filtering. If I do not do this, then I can not use the many > DSP filters to close down the bandpass which is centered on 1500. > > Also, if I use the dual PBT (and I frequently do), I would not be able > to eliminate interference above below 1500 Hz if I could only use the > upper filter. > > This is true for any digital mode operating with SSB or SSB-D, that I > want to be able to properly filter. > > 73, > > Rick, KV9U > > > expeditionradio wrote: > > >> > >>There are a few digital modes that it is much more common to use and > >>report USB dial frequency, rather than centre frequency, such as: > >> > >>Olivia (various flavors) > >>ALE (125bd 8FSK ATM and DTM/DBM ARQ) > >>MIL-STD 188-110 and derivatives (RFSM2400, etc) > >>CCIR 493 (100bd FSK) > >> > >>The above modes tend to be operated in "channelised" configuration, > >>always USB Upper Sideband. > >> > >>Olivia uses an ad hoc voluntary channel method, because it can decode > >>far below the signal/noise level which can easily be tuned manually by > >>an operator. Also, this helps operators to switch back and forth > >>through any of the Olivia flavors, keeping the lowest MFSK tone at > >>about 516Hz... whether using bandwidths 125Hz, 250Hz, 500Hz, 1kHz, or > >>2kHz. > >>See this image for the various flavors of Olivia: > >>http://hflink.com/olivia/olivia_flavors.jpg > >> > >>And this website for more Olivia info: > >>http://www.hflink.com/olivia/ > >> > >> ALE and Selcall uses a standardised channel listing based upon USB > >>dial frequency, and 188-110 stuff is usually associated with the same > >>ALE channels. > >> > >>73---Bonnie BA7/KQ6XA > >> > >>. > >> > >> > >> > >> > >> >
