It is my understanding that all users CAN NOT share the frequency "at the same time". Most high-speed connections are dedicated, I know pactor is. I am not sure about ALE, but from a cursory view, I believe it is also. Packet is the only protocol I know that is designed to share a frequency, but it is also a lot slower because of this. This is what I meant by a party line analogy. You have sequential use, not concurrent use of a given frequency.
This makes the analogy more like 10, 20, or 30 people sharing a PC or phone. Using the example of 60 minutes versus 10 minutes, each person has to wait 10 minutes multiplied by the number of people ahead of them. Plus you need a way to assign people in the sequence. Are you going to be willing to wait 10 minutes for your IM to be sent, even if it is sent quickly when you gain access? The original argument was that higher speeds allow faster sending thereby clearing the frequency quicker. However, this only works if people are willing to wait until their turn comes around. If they need or just simply want immediate access, as IM implies, they will use another frequency. This immediately reduces the spectrum efficiency of the wider modes. In many cases and even perhaps most, more narrow modes would work better to give instant access to more people in the same bandwidth as a wider mode. In other words, they can SHARE the same BANDWIDTH. My main point is that sharing spectrum is a complicated equation with many variables. A simple argument doesn't always take into account all the variables necessary to make an informed decision or it contains several assumptions that may or may not be valid. One of these assumptions implicit in the original argument is that people are willing to wait until the frequency clears to use it. That wait time may be seconds or even minutes (10 minutes in the example). It also implies that there is a method of queuing requests for the frequency or of collision avoidance. Neither of these assumptions were discussed or proven. Jim WA0LYK --- In [email protected], "John Champa" <[EMAIL PROTECTED]> wrote: > > Jim, > > The old telephone party line is a poor analogy. Think more along the lines > of IM when it comes to high-speed data users all sharing the same frequency > at the same time. > > 73, John - K8OCL > > > >From: "jgorman01" <[EMAIL PROTECTED]> > >Reply-To: [email protected] > >To: [email protected] > >Subject: [digitalradio] 3kHz or 500Hz Re: Updates on effect of FCC R&O > >Date: Sun, 22 Oct 2006 13:29:05 -0000 > > > >A couple of comments. The FCC must consider more than just how fast > >data can be sent. It must also consider how to maximize the numbers > >of users that can access a finite spectrum without waiting. > > > >Your point assumes there is queuing system of some sort for that 3 kHz > >of spectrum and that people will stand in line to use the frequency. > >In amateur radio there is no queuing system, you can only monitor a > >frequency until the qso finishes. There is no "grab a number" system > >to determine who uses it next. And, since qso's are generally random > >length, you may have to wait one minute or 30 minutes. The > >traditional way of bypassing this is to move to a clear frequency. > > > >It seems obvious to me that the FCC has decided that much more > >bandwidth for phone users is needed versus bandwidth for CW/RTTY/data > >(i.e., narrow bandwidth) users and that the narrow bandwidth segment > >should be shrunk. In doing so, they needed to decide how to "best" > >use the smaller spectrum, and that part of the determination was how > >to minimize the wait time for spectrum for the most users. > > > >I'm old enough to remember 2, 4, and even 8 party telephone lines. Do > >you know how much time was wasted in checking the line to see if it > >was not being used? There were lots of times it was quicker to drive > >to a neighbors or to town rather than wait for the line to clear. > >Frustration to the max! Telephone companies have dealt with > >maximizing the use on shared facilities for over a hundred years. > >They have sophisticated analysis tools that into account all kinds of > >variables. However, cusomter wait times is still the one variable > >that drives everything else. > > > >I'll bet I'm not the only ham who would chose wait time for an open > >frequency as being more important than length of qso. Perhaps the FCC > >is "encouraging" hams to develop a method of queuing for frequencies > >and qso times thereby maximizing spectrum use. I suspect a system > >like this would go a long way to letting the FCC expand bandwidths. > > > >Jim > >WA0LYK > > > >--- In [email protected], "expeditionradio" > ><expeditionradio@> wrote: > > > > > > There's another way to look at spectrum use. It is better to use a > > > 3kHz bandwith for 10 minutes than to use a 500Hz bandwidth for 1 hour > > > to pass the same traffic. On HF, with short propagation openings, it > > > is better to be able to quickly send the message. Approximately 3kHz > > > is the defacto worldwide bandwidth standard for HF communication > > > transceivers. > > > > > > This R&O isn't an issue of FCC making rules for "encouragement" to > > > produce narrower bandwidth signals. It is the result of someone at FCC > > > that is out of touch with reality. > > > > > > The Bigger Issue: The freedom to use existing digital worldwide > > > standards for HF communications is important for Amateur Radio. > > > > > > It is very much like the freedom to use existing analog bandwidth > > > standards such as SSB and AM voice. Should FCC take take that freedom > > > away also, under the guise of "encouraging innovation"? Should hams be > > > forced to develop 500Hz bandwidth voice modes? > > > > > > Or, should a wide range of communications methods be "encouraged" in > > > USA like it is in the rest of the civilized world? > > > > > > Bonnie KQ6XA > > > > > > > > > > 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/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/digitalradio/join (Yahoo! ID required) <*> To change settings via email: mailto:[EMAIL PROTECTED] mailto:[EMAIL PROTECTED] <*> 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/
