Alan Barrow wrote: > My view is that debates about digi-modes are tempest in a teapot. The broader issues are around impact of contesting, allowing for continuing to advance the state of the art, etc.
I think you hit the nail on the head. The broader issues encompass contesting, advancing the state of the art, contesting, etc. HOWEVER, it is not necessary to spread all over the bands just to "advance the state of the art" - specifically in this case, high-speed messaging on HF. Within the bandwidth of a phone signal, all sorts of experimentation is already available with minimal disruption to other communications. "If" a new mode shows enough promise to really advance the state of the art, "AND" will benefit other users of the bands, then it is appropriate to suggest the benefits to everyone for taking away space from other users and using the new mode instead.
The most recent example is the ROS "mode", which is very wide for the benefit it brings, in addition to being illegal on HF in this country because it unfortunately happens to use spread spectrum technology. The idea of spread spectrum is that many stations can share the same space (if the spreading is wide enough) because the probability of a collision of two signals is small. ROS fails technically because it is just unable to spread wide enough, limited by the IF bandwidth of most existing receivers (non-SDR types). So, the best the ROS author is able to do now is accommodate two ROS signals simultaneously, but in twice or more bandwidth than several more narrow signals (like Olivia), and with poorer performance besides. Because it was so wide, it could not find any place to operate except on one frequency in the automatic subbands without disturbing communications of existing, more narrow, modes. Still, experimentation was possible and continues. Whether or not ROS is better than even PSK31 or Olivia is still to be determined, but experimentation and improvement is still being done. If, after considering the bandwidth of the mode and all other users, the overall benefit of switching to ROS is there, I am sure a consensus will emerge to do that. As another example, PSK31 is very narrow and spectrum efficient at about a 50 Hz bandwidth, but fails totally over the polar path. MFSK16, eight times as wide, pr RTTY. does not fail, and neither does Olivia, so there is justification for using the wider mode in order to achieve something that is otherwise unachievable. Experimentation on a small scale first, then followed by deployment, "if" justified by consensus, is the way it needs to be done, and not the other way around as suggested by HFlink.
73 - Skip KH6TY
