The reason for using a frequency close to the beacons is to insure you don't step on the beacon, but still are able to operate with efficient spectrum use. We can surely all agree that we have very limited spectrum for the number of users, particularly during certain times of heavy use. If we kept far away from this one set of beacons, we would be giving up 6 or more KHz of space on each of those bands that have the IARU beacons: 20, 17, 15, 12, and 10 meters. I would view this as very poor amateur practice.
Even though I often disagree with Bonnie's ideas and the way she presents them, this is one time that she is clearly correct. When you put your SSB dial frequency on a given frequency you are actually NOT transmitting on that frequency with the typical digital mode. The dial frequency is the frequency at which your carrier frequency would be if you had a carrier. Of course, being that it is SSB, there is no significant carrier unless your equipment is malfunctioning. Even if you were on 14.100 USB, and you started transmitting with a 500 Hz wide mode and centered it on 1000 Hz, you are still going to be 750 Hz ABOVE the 14.1000 CW beacon frequency. This seems to be a very difficult thing for many hams to understand based on the comments we have been seeing lately. They somehow think that they are actually transmitting on their dial frequency. They most assuredly are not when they are transmitting with a tone or series of tones away from that frequency. Are you even sure you understand this? For example, have you really been on 14109.5? I might suggest that you were not on that frequency at all but were well above this frequency. It is rather difficult to connect with someone when they are perhaps 1500 Hz off from where they say they are. Lets suppose you decided to move to 14099 with a tone spread of 500 Hz and centered on 1000 Hz. Do you honestly think you would be clear of the beacon frequency because your dial was not on 14100? In truth wouldn't you be zero beat with the beacon and QRMing both sides for 250 Hz? ALE seems mostly an annunciator to let others know you are calling them or a group. Basically it is an adjustable SELCAL like we used to use for autostart RTTY in the very old days. I don't see this as ever being all that useful since we have had DCS on rigs for many years now and it is rarely used on VHF and higher bands. In terms of communication, the ALE operators are mostly going to talk or send messages via ALE after they connect. What I see much more valuable is the fact that this gives us a new ARQ mode for messaging. And it may interest others in coming up with adaptive technologies to allow us to transmit higher speed, yet error free data. KV9U John Bradley wrote: >The math is all fine and dandy , but WHY pick a frequency close to the >beacons? That's where all the logic fails! >There is a large chunk of relatively little used frequencies on both sides >of the beacon frequency. For argument's sake >why not make the guard frequency +/- 3 khz? why not clump the ALE >frequencies closer together since they reflect (usually) >the state of the art , or at least "modern" equipment since computer control >is required? > >The only redeeming virtue is that ALE operators spend much of their time >arguing and discussing ALE on email rather than on the air. >For the past few days I have been sitting on 14109.5, testing (playing with) >Patrick's new 141A mode. Basically have been monitoring >from about 1300Z to 0000Z, since I have also been working on a consulting >project on another computer in the office. > >The only things I've heard are other folks playing with the same mode, no >soundings etc etc from the ALE folks. This is a good thing, since they are >so determined to potentially QRM the beacon frequency, the incidence may be >fairly low. :) > >John >VE5MU > >
