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#11
August 26th 05, 05:54 PM
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K4YZ wrote: an_old_friend wrote: wrote: Dan/W4NTI wrote: wrote in message ups.com... Dan/W4NTI wrote: cut Tell you what Jim, listen during a RTTY contest weekend. Like when the NAQP CW is on this winter season. That's a different story. It is just an example of what it will be like with massive digital action. Just watch and see. All the more reason to have a reasonable Morse Code only subband. Say 7000 to 7050. why? why is it that Morse Code supporter are always insisting that Morse Code needs props in order to survive? Nope. It needs reasonable bandwidth in order to avoid interference. All modes need reasonable bandwidth in order to avoid interference. OOK signals to not mix well with digital and modes such as PSK31 But not because of bandwidth. are plenty of spaces left in a natural state and protected for those "hobbyists". Why not for Morse Code? They are not left just for theose hobbists. Many hunderd acres ar ein this area and never hiked to preserve the tree and lifefroms like deer and wolves and Mtn lions "those" "hobbyist" "lifeforms" Sure they are left for "hobbyists", although in your example "naturalists" is the appropriate term. There are wilderness areas/preserves where human access is strictly limited in an attempt to maintain the "wild" nature of the place. The radio analogy to such preserves is the quiet zone (both geographic and spectrum) around some radio astronomy observatories. But that's not what I'm talking about. There are parks, recreational areas, seashores, lakes, and other areas reserved from "development" and access in various ways. The rules for their use are aimed at letting "hobbyists" have the best possible experience (as in "fun") from the area - even though the rules limit the use of the area by some. For example, there are plenty of such places where motor vehicles are simply not allowed. In many cases the only way to reach such places is to walk in and walk out. The presence of motor vehicles would change the place, and the experience, so much that they are simply not allowed. There's a nature trail near my home that just opened last fall. Used to be an interurban right-of-way. It's a favorite for walkers, runners, bicyclists and rollerbladers. No motor vehicles of any type are allowed, even though the surface is paved. At the other end of that spectrum is the Appalachian Trail, stretching from Stone Mountain in Georgia to Mount Katahdin (sp?) in Maine. No motor vehicles or even wheeled vehicles allowed on most of it. Does walking need "props" in order to survive? the question is why is Morse Code entitled to a such a preserve all to itself? Why not? The ONLY mode that OOK is compatable with is Single Side Band. In some ways yes, but in most ways no. Even those two modes are incompatible in many ways. That's why they have separate subbands. Consider the fact that most "data" modes are not allowed in the voice/image subbands. Is that a "prop" so that SSB and AM will survive? Imagine a stretch of band where there are Morse Code signals every 1 kHz. Is there anyplace in such a band where an SSB voice signal can operate without causing interference to at least one Morse Code signal? And why if it is Such an EFECTIVE mode does it need the protection? "EFFECTIVE" 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. 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. 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. 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? 73 de Jim, N2EY |
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