Dave Bernstein wrote: >>>> AA6YQ comments below > > --- In digitalradio@yahoogroups.com, "Jose A. Amador" <[EMAIL PROTECTED]> > wrote: > >> snip< > > There are physical mechanisms in radio propagation that creates > hidden stations. So do losses, distance, natural obstacles, and > finite propagation paths. I even had thought it was a well known and > accepted fact by knowledgeable people. But seems it isn't, at least, > yet. > >>>> If you check this reflector's archives, you'll find messages >>>> from Steve K4CJX, a member of the Winlink team, claiming that there is no >>>> hidden transmitter effect.
Well, with all due respect, I stand on my own words. If Steve Waterman said so, I don't know, and don't know why and on which context. Nevertheless, I am not the only one convinced of the fact that nobody hears everybody, always. If it wasn't true, as one different example, cell phones could not exist. >>>> Yes, hidden stations are absolutely a fact of life on HF. Why >>>> then would anyone deploy an unattended station that relies on a remote >>>> initiator to ensure a clear frequency when this scheme clearly fails >>>> in a hidden station scenario? If the other user on the channel would be in the same mode, carrier detection on the PTC itself would stop the answer of the PMBO. What you are demanding is that they use multimode activity detectors. That is something else. I repeat again, it did not happen on packet, and did not happen with APLINK or Winlink Classic. >>>> Your argument seems to be "because there can be hidden >>>> stations, its okay for unattended stations to QRM them". No, I did not. Don't put your words in my mouth. >> snip< > > Radio has been proved not to be an ethernet backbone on which > everybody hears everybody all around the world. > >>>> Agreed. And so deploying unattended stations whose considerate >>>> operation requires that everybody hear everybody is irresponsible. I believe a bit of knowledge of history is in order. Winlink 2K evolved from previous technology, which, as far as I know was never disputed, because everybody accepted that certain frequencies were used and their carrier detectors only detected the same mode. The road to hell is certainly paved with good intentions. Rick Muething attempted to do it better and please more people. But his work has only opened the grounds for some other people to start even more attacks. It is really sad. <SNIP> >>>> Railroad tracks are an indisputably obvious marker, and their >>>> right-of-way is owned by the railroad; if you camp on railroad tracks >>>> and are struck by a train, its your own fault. So far we agree. >>>> There are no such >>>> obvious markers on frequencies in which unattended operation is >>>> permitted, the frequencies available for unattended operation vary >>>> from region to region, and these frequencies are not exclusively >>>> allocated to unattended operation. No unattended station can QRM a >>>> pre-existing QSO on the grounds that it "owns the right-of-way". There is a window opening in 2009, with new ham bands limits. It seems that there is more harmonizing work to be done by IARU. <SNIP> >>>> There is no secret sauce in the SCAMP busy frequency detector; >>>> Rick KN6KB prototyped it quickly, and was surprised by how well it >>>> worked. Rick has proved to be really brilliant. Is then such a source or algorithm already in the public domain ? If it is so, why isn't it already known and widely available? Can you elaborate on this? Can you provide a link to it? >>>> Furthermore, Rick is a member of the WinLink Development team; >>>> he could extend the existing WinLink PMBO implementation to include the >>>> SCAMP busy frequency detector, were the WinLink organization >>>> interested in reducing QRM. Worst case, the cost would be an >>>> additional soundcard for each PMBO. You are here again demanding them to please you. I believe it is clearly off-topic on this list. <SNIP> > What all of this should be is about getting someone capable enough to > come forward with a working solution available to all. So far, all > the previous preaching has proven unable to achieve so. > >>>> There has been not one report of failure by any developer >>>> attempting to build a busy frequency detector for use in unattended >>>> stations. Why? Because it works perfectly well, or because nobody has achieved it entirely? >>>> The one well-reported attempt to build a busy frequency >>>> detector succeeded beyond expections, but inexplicably has not been >>>> deployed. Well, we are reaching a point where people will be afraid of publishing their findings, because their ideas can be used in more ways than what they foresaw, and with opposite ends. It is really sad... > Haven't we had enough of it already? > >>>> I will stop debunking fallacious arguments when they cease to >>>> be made -- or when someone demonstrates that they aren't fallacious. So we arrive to a new definition of fallacious: whatever does not fit your own mental scheme. Certainly, we can see all you are attempting to do is exhausting those who disagree with you...but that by itself still does not solve the problem you have been heralding. We need something more than mere words about multimode activity detectors. Can't we also agree on this? 73, Jose, CO2JA __________________________________________ Participe en Universidad 2008. 11 al 15 de febrero del 2008. Palacio de las Convenciones, Ciudad de la Habana, Cuba http://www.universidad2008.cu
