If there were documentation on ROS then there would the possibility of investigating the problem further and maybe adding improvements. Part of the problem is that even if there is a large degree of spreading compared to the data rate, the channel is still quite narrow and a large portion of it subject to the same disturbances or interference. This is similar to what happens with the various commercial broadcast digital systems. The wider ones are much more robust, especially in regard to multipath, even though the data payload was increased in proportion.
KH6TY wrote: > > Simon HB9DRV wrote: There's a lot more to Olivia than being > multi-tone MFSK. >> >> >> >> > I am aware of that, Simon. > > However, Olivia is currently the most popular digital mode other than > PSK31 and RTTY, and the question was if ROS 16 baud was worth using > twice the bandwidth of Olivia. We hoped that it would be, because on > UHF, space is not at a premium as it is on HF, but ROS 16 baud, (the > spread spectrum variation) at 2250 Hz width, was not even as good as > SSB phone under the fast Doppler flutter conditions. So, as a choice > of modes currently available, either MFSK16 (my personal preference on > HF, but impractical on UHF due to the necessity to tune so accurately > and have little or no drift) or Olivia, is a far better choice than > ROS, and performs better. > > We would like nothing better if there were a mode that outperformed > Olivia at equivalent typing speed, and could copy further into the > noise than Olivia can, and is more tolerant to mis-tuning or drift > than MFSK16, but so far ROS is not the one. As things stand, CW > (decoded by ear) is currently the "last mode standing", but it seems > it must be possible to come up a mode that can beat CW under the > typical conditions found on UHF. > > 73 - Skip KH6TY > > >> >> >
