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#1
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Why don't voice radio communications use FM?
Perhaps this is a naive question, but: Why don't voice radio
communications for aviation use FM radio instead of AM radio? I realize there's substantial inertia in the installed base of AM equipment, but surely one could allocate some new frequencies to FM and use them in parallel for some years to ease the transition. The reason I ask is that improper and misunderstood radio communication is a leading cause of accidents, and so it seems that anything that can make that communication clearer would greatly improve safety. I can barely understand what I hear on the radio. It is true that the communication is very standardized, making it easier to guess what is being said, but the results are pretty unpleasant if one guesses wrong. On a related note, it has occurred to me that one could develop voice-recognition systems that understand the speech of a pilot and then repronounce what he says in an extremely standard synthetic voice. This could also improve understanding, especially for non-Anglophone pilots who speak with heavy accents. The same systems could clean up the speech so that it is absolutely standard, with no missing or added words. Of course, the issue here is that the system would be stuck if it cannot recognize what is being said, or if a completely non-standard utterance is made by the pilot. A natural extension of this would be systems that recognize standard phrases in one language and translate them to another, but that would be even more dangerous if the system ever failed. Still another idea is special training systems that listen to a pilot's speech and transcribe it, and point out any problems with understandability. Again, this would be most useful for non-Anglophone pilots, but it would work for anyone. If a machine can understand a pilot's speech clearly, then a human being should certainly be able to understand it that much more easily. -- Transpose mxsmanic and gmail to reach me by e-mail. |
#2
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Why don't voice radio communications use FM?
"Mxsmanic" wrote in message news Perhaps this is a naive question, but: Why don't voice radio communications for aviation use FM radio instead of AM radio? Wouldn't that reduce the available frequencies? |
#3
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Why don't voice radio communications use FM?
Yeah, Steve, it would. But I think we might be able to swap (on a long term
swap basis) the VHF com band for stuff up between 600 and 900 MHz. that have very limited usage. Not only could we get way more bandwidth, but the antenna size is cut by a factor of 6 or so. Jim "Steven P. McNicoll" wrote in message nk.net... "Mxsmanic" wrote in message news Perhaps this is a naive question, but: Why don't voice radio communications for aviation use FM radio instead of AM radio? Wouldn't that reduce the available frequencies? |
#4
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Why don't voice radio communications use FM?
Steven P. McNicoll writes:
Wouldn't that reduce the available frequencies? For a given audio bandwidth, FM tends to require somewhat more radio bandwidth, as I recall, but the audio bandwidth of aviation radio is already so limited that I don't think this would be an issue. The gain in clarity would outweigh any loss of audio fidelity, assuming that the same channel widths were used. If frequencies were reallocated (instead of allocating new ones), that would be different. That would also obsolete older equipment much more quickly, which might not be acceptable. But there must be some space somewhere that could be added to the frequencies, or perhaps some band so rarely used that it could be reassigned. -- Transpose mxsmanic and gmail to reach me by e-mail. |
#5
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Why don't voice radio communications use FM?
You recall incorrectly.
Jim "Mxsmanic" wrote in message ... Steven P. McNicoll writes: Wouldn't that reduce the available frequencies? For a given audio bandwidth, FM tends to require somewhat more radio bandwidth, as I recall, |
#6
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Why don't voice radio communications use FM?
RST Engineering writes:
You recall incorrectly. Perhaps. Theoretically it should require exactly the same bandwidth, but I seem to recall reading that typical implementations used more bandwidth. In any case, you don't need much for voice communication. The advantage of FM would be the reduction of noise. Digital over FM would be still better. -- Transpose mxsmanic and gmail to reach me by e-mail. |
#7
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Why don't voice radio communications use FM?
Mxsmanic wrote:
The reason I ask is that improper and misunderstood radio communication is a leading cause of accidents, A leading cause of accidents? Where did you get this statistic? but the results are pretty unpleasant if one guesses wrong. Guess? If a pilot or controller is not able to comprehend the other side's transmission, there is no guess. "Say again?" is the phrase of choice and it is used all over the frequencies. -- Peter |
#8
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Why don't voice radio communications use FM?
Peter R. writes:
A leading cause of accidents? Where did you get this statistic? From the NTSB and several books on the subject. Guess? If a pilot or controller is not able to comprehend the other side's transmission, there is no guess. "Say again?" is the phrase of choice and it is used all over the frequencies. It's routine in linguistics to unconsciously guess. A person listening to familiar sounds in a familiar context will "fill in the blanks" for any sounds that cannot be unambiguously distinguished, and he will do this without thinking. If he guesses wrong, trouble can result, and accidents have happened in aviation for this reason (the most famous probably being the one at Tenerife). -- Transpose mxsmanic and gmail to reach me by e-mail. |
#9
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Why don't voice radio communications use FM?
Mxsmanic wrote:
From the NTSB and several books on the subject. Have a name of one of these books that claims that aviation communication is the leading cause of aviation accidents? It's routine in linguistics to unconsciously guess. A person listening to familiar sounds in a familiar context will "fill in the blanks" for any sounds that cannot be unambiguously distinguished, and he will do this without thinking. You imply that this is a very common occurrence. Sorry, but I am unable to accept your premise without some evidence to back up this claim. If he guesses wrong, trouble can result, and accidents have happened in aviation for this reason (the most famous probably being the one at Tenerife). My understanding of the accident at Tenerife is that it had more to do with a fateful heterodyne and a captain who was asserting his own way, rather than misunderstood communications. -- Peter |
#10
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Why don't voice radio communications use FM?
Peter R. writes:
My understanding of the accident at Tenerife is that it had more to do with a fateful heterodyne and a captain who was asserting his own way, rather than misunderstood communications. Some of the words on the cockpit recording are impossible to understand even today. That's pretty strong evidence that misunderstood communications had an important role in this accident. In fact, there are several instances of misunderstood radio communication involved. -- Transpose mxsmanic and gmail to reach me by e-mail. |
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