Hello Alan,
Thank you much for your reply. To tell the truth, I did not subscribe to this group in those beginning days ( posted only om ROSMODEM ) It is so sad, that because of the noise, anti ROS biases, agenda's intelligent exchanges are just about impossible, pro and con. ( IMHO ) Every tine I think to understand why ROS is illegal a couple of days later, I am getting confused. -Bandwidth. -The real properties of FHSS -Is WSJT FHSS?" Why , why not. -Why is WSJT65C legal ( just a rhetorical question ) -Is wide band Oliv1a FHSS Why, why not. -Being in public domain. -Specs published. -FCC and others able to monitor content. -ROS transmitted signals not the same from one transmission to another for same message -ROS transmitting while idling -Oversold by am young(?) software engineer not being familiar with US rules. Just to name a few. It is of course because of my limited intelligence, that is clear 73 Rein W6SZ > worse than a narrower mode is flawed. Otherwise we'd all be using RTTY. > FEC increases bandwidth for the same data rate, but the trade off > surfaces over sustained measurement in real (difficult) HF conditions. > Skip's work did show there was not a big win for ROS, so we arrived at > the right spot. But many were banning just because it was wider than > their favorite mode! > > - Lack of consideration that multiple SS signals could occupy the same > spectrum, effectively decreasing the total required bandwidth. There is > a point of diminishing returns, and ROS may not fare well. But if I > could stack a dozen or more data signals simultaneously in a single SSB > width slot, would that be a bad thing? Or what if a AF type SS (AFSS?) > mode could live on a non-interference basis, should it be banned just > because it was technically SS? No testing was done that I'm aware of > that would have allowed real world throughput to be measured with > multiple signals on the same channel. This is one of the big wins of DSSS! > > - Assumption that the current FCC reg is the end all. It was accurate > for state of the art when added. But no one foresaw that DSP's would > allow an audio based SS implementation inside a SSB bandwidth. The FCC > reg was written to address the then current DSSS modems which used > spreading factors of 100x with direct IF injection, etc. And are totally > inappropriate for HF usage. Put another way, most professional RF > engineers would consider any audio based scheme to not be DSSS as it's > just not how it's done. Pretty much all real world DSSS systems use IF > level modulation to the point that it's one of the main identifying > characteristics. > > - Very inappropriate involvement of the FCC. This is absolutely not the > way to approach a new mode, the answer is nearly always "check the regs". > > One thing we can probably all agree on is that ROS is pretty much dead > for consideration in the US. The waters are too muddied at this point. > > I'm more concerned about impact to the next innovation. > > And the fact that all the noise & behavior set aside, the author did > implement something new that should have been evaluated on it's merits > before declared illegal via trial by yahoogroup. (Before he hastened > it's demise due to his own unprofessional behavior). > > Personally, this episode just cements my believe that the US will be > trapped using legacy modes & arcane restrictions for the most part until > some form of bandwidth based bandplan approach is implemented like much > of the civilized world. > > Lest we crow about some of the more recent innovations, we have to > factor in that rtty still rules the airwaves from a number of users and > usage perspective. > > And it's about as inefficient a mode we could come up with when impact > to the spectrum is factored in. (medium power, wide sidebands, single > user per channel, etc). Call me when there is a weekend with as many PSK > signals on the air as one of the (too frequent) RTTY contests. > > I'm not opposed to RTTY, exactly the opposite. But it's the RTTY centric > regs that hamper our development. Even things like P3 & winmor are > having to go the long way around to maximize performance while not > running afoul of the arcane RTTY based regs. (Much less use of tech like > the FS-1052 modems, etc) > > Have fun, > > Alan > km4ba >
