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 >> >>. >> >> >> >> >>
