On Tuesday 24 January 2006 12:37, KV9U wrote: > > -- the semi-automatic stations will be able to operate anyplace on the > bands that their BW permits. I personally oppose this and want all > stations that operate in any kind of automatic status to stay in a > subband unless they have adequate busy channel detect.
Because of the hidden transmitter effect, adequate busy channel detection will probably not be sufficient to alleviate problems. Scenario --- A semi-automatic robot in St. Louis monitors 14200khz. On Sunday morning a large number of hams in 6-land are in qso - hearing distance from St. Louis. Because of its busy detection system, the robot in St. Louis will not answer queries being made from end user clients around the east coast. This is what we used to call a "killer trunk" in the telecomm business. The channel continually looks idle and originating call after originating call gets hung up on the channel. By the time the 6-land qso's end, the channel will be so loaded with call requests from the east coast that it is doubtful that they can all be cleared. Many of these originating stations won't be able to hear each other and they will just keep on initiating call after call, interfering with each other at the robot site thus keeping the robot from establishing contact with anyone. Since blocked calls are not cleared from this system, clearing the backlog could take a very, very long time thus denying the frequency from users for an extended period. This is the reason that any kind of automatic operation needs to stay in a sub-band, regardless of busy detection ability, until traffic controls associated with efficient trunking can be implemented as well. These controls would include: 1. one frequency per hub station (no killer trunks) 2. clearing of blocked calls (a short "channel busy" response to calling stations, i.e. no killer trunks) 3. frequency sharing between hubs (good busy detection will advance this capability) 4. Queued operation for store and forward systems rather then immediate response operation. (separate data and control channels would help this) Badly designed systems should not be rewarded with access to ever more spectrum for use in horizontal spreading of ever more inefficient access channels. Restriction to limited sub-bands *force* good system design and efficient use of spectrum. We can artificially impose those sub-band limits or wait until the system hits an un-imposed limit. Such un-imposed limit being band edges or ModeWar/PowerWar limits set by competition with others. Neither of these un-imposed limits promote good spectrum efficiency for amateur radio. > > -- wider BW modes (> 500 Hz) are not going to be able to operate where > they do now. They would be forced to move up. Examples are above > 14.100, 7.100, 21.150, etc. So many of us who typically work within the > first 100 KHz of a given band are going to have to move whether we like > it or not. No one likes to give up priveleges, but this proposal is > going to cause it, should it go into effect. > > -- although the voice and wider digital frequencies are the same > subband, from what ARRL has said, there will still be a bandplan that > will likely keep the digital modes away from the analog voice modes. A > lot depends upon how well things work out. With the current spot digital > and analog image frequencies, along with analog voice, there does not > seem to be much of a problem. But there are only a few operators. > A voluntary bandplan with no enforcement mechanism will not keep digital away from analog unless the demand for spectrum by each (i.e. digital/analog) allows it to happen. If the demand for spectrum by each is so low that such a scenario will be played out then what is the driver for implementing some new paradigm of regulation at this point in the space-time continuum? If digital has enough room and analog has enough room then what will be accomplished by the regulation change? If they don't have enough room, then the regulation change won't help since it doesn't widen the amateur bands. In fact, it exacerbates it by throwing digital and analog of similar bandwidths together. If you've stayed with me so far or have jumped to the end, the bottom line of all this is that neither of the proposals on the table at the FCC have given any where near enough time and effort to analyze where we are today and what the proposals will cause to happen. They both just offer up platitudes and boundless wellsprings of optimism that say "OUR PLAN IS BETTER!!!" with exactly no rational explanation of why they are better or will result in better things for amateur radio let alone the digital modes. Since the ARRL plan will absolutely *force* variable bandwidth transmission methods into the wide bandwidth area, thus forcing them to compete with phone and other digital protocols only capable of wideband operation, the plan will actually *hurt* experimentation with spectrum efficient, bandwidth adaptable modes in the future. Yet the ARRL didn't even see fit to address this in their plan. Is that because they weren't bright enough to even recognize the issue, was it because they didn't spend enough time investigating the issues fully, or was it because they just plain didn't care about spectrum efficiency and had other objectives? tim ab0wr Need a Digital mode QSO? Connect to Telnet://cluster.dynalias.org Other areas of interest: The MixW Reflector : http://groups.yahoo.com/group/themixwgroup/ DigiPol: http://groups.yahoo.com/group/Digipol (band plan policy discussion) Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/digitalradio/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
