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#11
August 26th 05, 11:26 PM
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Michael Coslo wrote: wrote: snip There's a fundamental divide appearing in radio modes nowadays. Modes like Morse Code and the analog voice modes are real time, "direct experience" modes. A human listens to the demodulated signal directly, in real time. The "digital" modes are fundamentally different in that there is decoding beyond the demodulation process. A machine does the decoding - the human does not 'listen' to the signal at all in most cases. Which is great for people such as myself! Agreed! One more tool in the toolbox. Look at PSK31 - you see a particular pattern on the waterfall, click on it, and the decoded text appears. If there is interference, the text is garbled, and there's not very much you can do about it. And what you can do is a matter of equipment adjustment, not skill in listening. Thank goodness for that! If listening skill was the main criteria, I wouldn't be much of a Ham! Well hearing skills maybe..... Actually, Mike, your *listening* skills are probably excellent. Because of this difference, it makes sense to allow certain modes - like Morse Code - a place free of interference from "machine modes", just like the trails where motor vehicles are not allowed. I'm certainly all for keeping those accursed robot stations in their own section of the bands (actually, I am not in favor of their existance - I think they violate the spirit if not the law). Repeaters, satellites and beacons are robots of a sort. Should we ban those too? How is a robot station that wipes out sometimes dozens of QSO's any different from certain Amateurs who have been known to broadcast "bulletins right over top of ongoing QSOs? Several important measures: 1) Does the bulletin station operate on a published schedule of times and frequencies? 2) Does the bulletin station transmit only information of clear and special interest to radio amateurs? (IOW, not general news and such?) 3) Is the bulletin station using an approved method of control? Voice modes like SSB and AM are protected from modes like PSK31 and RTTY. The spectrum allowed to those modes in the US HF ham bands amounts to more than half the total spectrum available! If such protection is good enough for SSB and AM, why not Morse Code? I have to smile at the concept of SSB and AM being protected from my wimpy little PSK31 signal. But they are! You can legally transmit PSK31 anywhere on the HF ham bands where voice modes are *not* allowed. Why does SSB need protection from PSK31 but not Morse Code? This sort of thing has some odd ramifiactions. Imagine if you wanted to use a combined text/voice mode. Such a mode might use SSB *with carrier* for the voice part, with the carrier phase-shifted to send the text. Such a mode is not allowed on amateur HF. One can even imagine a mode consisting of SSB on one sideband, SSTV-type images (digitally encoded) on the other, and text on the phase-shifted carrier. Something neat to try out, huh? Except it's not allowed on the amateur HF bands either. Butfull-carrier double-sideband AM voice is allowed. In both cases the prohibition is not due to the bandwidth used but because of the content (voice/image vs. text) I understand your analogy, but I don't think it quite hits the fundamental divide point. Certainly RTTY and SSTV and ATV and HELL mode have been around for quite a while. Sure - but they've been of limited use until recently because of the difficulty of implementation. With the drastic reduction in the cost of a computer, the increased computing power, and the wide selection of easy-to-use freeware, the game is very different than even 10 years ago. Of course none of this prevents someone from having "happy fingers".... 73 de Jim, N2EY |
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