A couple of minor comments: 97.3(a)(9)/ Beacon/. An amateur station transmitting communications for the purposes of observation of propagation and reception or other related experimental activities.
ALE as is normally used, is actually operated as a selective calling and linking interface. Rather than "beaconing" (transmitting without being interested in responses) specifically for propagation purposes, it is primarily doing a "de CALLSIGN, here I am if you want to talk to me". The much vaunted propagation aspect is actually a secondary characteristic: While it's designed to speed up links, it does so by effectively sorting the bands in order of probability of success. This is good both because it reduces congestion on frequencies that wouldn't have succeeded for a link between this particular pair of stations. If that's beaconing, so is the user who leaves his keyer sending CQ. As far as the "decode and understand" of a QRL response, an ALE or other automatic (as opposed to unattended ;-) station does not need to understand the response, since the presence of *any* response is sufficient to tell the automatic station that the channel is in use. Basically, the existing occupant merely has to transmit *anything* within x seconds of the QRL? and the busy detector should notice it. It shouldn't be too difficult to add a user-configured option to the common ALE software implementations that does QRL? in 5 wpm CW, then waits 10 seconds before otherwise transmitting. That way we could see if it's useful in practice rather than continuously discussing it in theory. (on the pro side, it fits the expectation of other hams; on the con side, it jams the frequency about as effectively as a short sounding does, but without actually getting the job done) There's a good chance that the ALE software could gain 99% of the advantage available by simply listening an additional 5 seconds to the channel before transmitting. Basically, just add a longer listen window to the state machine in front of all "initial transmit on this frequency" cases, except cases where the frequency is known by the software to have been in use for valid ALE traffic within the past minute or so (in which case any interrupted QSOs chose to set up on a busy frequency, so they are the interlopers, not the ALE traffic)
