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Question About Using AM mode on HF
- Thread starter Sonwatcher
- Start date
"Hams are supposed to measure this? They can't even look up the rules properly."
I can certainly see where that measurement may not be all that 'exact', but it's certainly measurable by anyone with a half way decent receiver. As for "can't even look up the rules properly", if you'd change that to "don't bother looking up the rules properly", I'd be willing to agree with you. Sort of a difference there, wouldn't you say?
Signal bandwidths for particular modes is also fairly easy to find. The way in which they are stated may have changed, but the 'widths' haven't. Wouldn't figure I'd have missed something as significant as that, really don't think I did. Or if they have changed, please show me/tell me where. Can't find them in the current edition of Part 97? Have you tried taking a step or two back from the current edition? If it hasn't been specifically stated as changed, I have to think that thy haven't been. That's how the rest of it works.
- 'Doc
I can certainly see where that measurement may not be all that 'exact', but it's certainly measurable by anyone with a half way decent receiver. As for "can't even look up the rules properly", if you'd change that to "don't bother looking up the rules properly", I'd be willing to agree with you. Sort of a difference there, wouldn't you say?
Signal bandwidths for particular modes is also fairly easy to find. The way in which they are stated may have changed, but the 'widths' haven't. Wouldn't figure I'd have missed something as significant as that, really don't think I did. Or if they have changed, please show me/tell me where. Can't find them in the current edition of Part 97? Have you tried taking a step or two back from the current edition? If it hasn't been specifically stated as changed, I have to think that thy haven't been. That's how the rest of it works.
- 'Doc
OK Doc. Please post a link to a current Part 97 CFR rule which specifies mode bandwidth using numbers or even remotely suggesting a measurement technique to prove compliance.
Teh thanks.
Some ill-informed people at the ARRL and FCC have repeatedly tried to push explicit bandwidth regulations down amateurs' throats -- but, so far, thank God, they have failed. Amateur radio is an experimental service and people have the absolute right to experiment with wider-bandwidth audio and wider-bandwidth modes.
Contrary to the first-grader-type understanding ("nobody needs more than 3 kHz!!! Narrower is always the way to go!!") of some amateurs (even some influential ones), wider bandwidth can actually increase effectiveness, and some wider modes can actually increase spectral efficiency. "Poisson, Shannon, and the Radio Amateur" was published in Proceedings of the IRE in 1957, for God's sake. It scientifically debunks the "narrower is always better" claims that have plagued amateur radio since the 30s. People should read it.
There should NEVER be any bandwidth limitations in amateur radio. It is an EXPERIMENTAL service. It is NOT a "channelized communications system" where everyone must sound like a telephone so that channels don't overlap. The day it turns into that is the day it dies.
Contrary to the first-grader-type understanding ("nobody needs more than 3 kHz!!! Narrower is always the way to go!!") of some amateurs (even some influential ones), wider bandwidth can actually increase effectiveness, and some wider modes can actually increase spectral efficiency. "Poisson, Shannon, and the Radio Amateur" was published in Proceedings of the IRE in 1957, for God's sake. It scientifically debunks the "narrower is always better" claims that have plagued amateur radio since the 30s. People should read it.
There should NEVER be any bandwidth limitations in amateur radio. It is an EXPERIMENTAL service. It is NOT a "channelized communications system" where everyone must sound like a telephone so that channels don't overlap. The day it turns into that is the day it dies.
And because a license is issued it is a privilege and NOT a right to experiment. Wider audio bandwidth simply adds to the QRM on the bands especially from the really higher power stations and again especially from those who adopt a " the hell with them. I am all that matters and my ego needs to be stroked" attitude which really seems to come out a lot on contest weekends. Wider audio bandwidth can sound better but amateur radio is a communications service and not a broadcast or entertainment service and as such really wide bandwidth is not necessary nor conducive to good operating practices. Many stations have proven that with some audio tailoring it is indeed possibile to have great sounding audio while maintaining a 3 KHz bandwidth. Believe me I know what wide audio bandwidth sounds like. I spent 22 years as a commercial broadcast engineer at both AM and FM stations but there is no way I would ever want to see 8 and 10 KHz wide audio on the HF bands. If anyone wants that kind of bandwidth then they should hit the VHF or UHF bands and put them to use in an effort to preserve them before we lose them.
No, it's an experimental service -- not a collection of "comm channels."
The good-quality AM guys and eSSB guys are 100% right. The "keep it narrow" guys are wrong and believe in myths -- like "narrow is more intelligible." It isn't. I have, by the way, been a broadcast engineer since 1976 and an amateur experimenter since 1972.
But, if you think 3 Khz audio is more intelligible that 5 kHz audio, I have no right to stop you from experimenting with it if you like -- just as neither you, nor any FCC commissioner, nor any legislator has any right to prevent me from experimenting with DSB, wider audio, PDM, companding, quadrature modulation, or any other technique -- on HF or VHF.
We have had the ability to experiment with all these things with utter freedom since the beginning of amateur radio, and there is no reason to take that ability away: none. Only a control freak mentality would try to legislate otherwise.
Sadly, I see that control freak mentality in amateur radio daily. I can hear them now:
"The Guys Who Know have all decided we must use narrow SSB now. The Big Guys at the League have determined that all you need is 3 kHz, so I believe them. Who are YOU to question that? If you want to run anything outside those parameters, you are doing something WRONG!"
What a limited mentality. Such people should have no power. They are not experimenters. They are followers. They decide nothing for themselves, but they vigorously defend the ideas they read in an official book somewhere and that are "generally accepted."
Experimental and educational amateur radio at its best is like open source software. Anyone can modify it and do it differently. Putting bandwidth (and, for that matter, mode) controls on amateur radio is like making it proprietary software -- you can only press the button and talk, since the "rules" prevent you from changing the button's functions, or adding a thousand new buttons. You get the picture.
For just two tiny examples of how the prevailing attitudes are questionable on the subject of amateur radio audio:
Look at the prevalence of distorted, heavily processed, clipped audio on the amateur bands. It is often argued that such audio "gets through" better in high noise conditions compared to clean, lightly processed audio. But even if that's true, you are punishing 90% of your listeners -- who could hear you fine and with much better fidelity, and a much better overall experience of your voice and personality, with clean audio -- just to make sure that a tiny percentage of folks on the extreme edge of your coverage range can understand you. (Reminds me of the broadcast loudness wars -- misinformed people making the decisions, and ruining it for everyone.)
And, if "bandwidth conservation" is so important, why use voice communications at all? Digital modes like CW can get the message through in 1/100th of the bandwidth, so aren't you being an outrageous frequency hog to use radiotelephone?
Well, no, not really. Voice allows the personality, the inflections, the emotional subtleties to come through that are entirely lost in text communication. So the extra bandwidth of voice _is_ justified to the more sensitive people who appreciate such things. *And the same is true -- in spades -- of wider bandwidth, higher-fidelity voice.* eSSB or good quality AM, with at least 5 kHz of audio and some decent low end response, allows -- in the subjective impression (and such impressions are all we have) of many operators -- at least ten times the personality and emotions and subtleties to come through than narrow, pinched SSB. It's worth it.
Listen to some excellent eSSB:
http://liberty.3950.net/K2WS-K4UU-NU9N-WB9DNZ-etc 3630 kHz LSB 20121229 840pm et 7500 Hz bw.mp3
Now it may be that some people can't tell the difference. They have "tin ears" or age-related hearing loss. But their perceptions needn't rule everyone. Just like blind men have no right to paint over the Sistine Chapel's ceiling because the gawking crowds are causing them problems.
I agree with some of what you say but not all of it. One of the big issues with, as you said over processed and clipped audio, is that most people truly do not know what good sound really is. A large percentage seem to think that the 11m mentality of loud-and-proud is the way to go. The louder they are and the sharper the freq. response they have then the better they will punch through.It sounds like crap most of the time and is very annoying to listen too especially for extended periods of time. On that part we agree. Then again most of those are of the "I am all that matters" crowd. You know the ones. They HAVE to make that contact regardless of how much power they use or who they step on to get it. that mentality will NEVER change regardless of anything else. It is not technical based but rather ego based. As for it being an experimental service,I agree. What I meant above when I said I disagree is that having an amateur license that enables one to experiment is a privilege and not a right. I guess I worded it wrong the first time. As for bandwidth limits. I still think there has to be a limit somewhere. The last thing i would want is to see a proliferation of wideband FM signals cropping up on HF. One of the driving forces behind the movements seems to be to allow for the deletion of sub-bands. We have had no such regulations here in Canada for years and it had never lead to a problem except when some US ham gets pissed that we are using SSB on 14.100 and starts screaming that we are out of band. :laugh: We have bandwidth limitations but for 99.9% of what goes on on the amateur bands it is sufficient. For those very few that want to experiment with non-standard modes or emissions they can get a special license to experiment with those modes.
Thanks for the civilized response. I do get a bit passionate about this issue.
Let people decide their own limits. Most people are decent and won't step on existing QSOs, no matter what the mode. (And indecent people can always find a way to hurt others, no matter what the rules.) The wider-bandwidth guys generally never fire up their 7.5 kHz audio in the general band during crowded conditions. But on 75 during the day, or in the advanced or extra sections where there's plenty of room -- sure, why not?
160 meters has no sub-bands for different modes or bandwidths, and, with vanishingly small exceptions, everyone cooperates very well.
I got into amateur radio through SWLing in the late 1960s. The distorted, narrow signals that were touted as "state of the art" back then would never have attracted me. What interested me were the discussions of the mostly young, free-thinking, hi-fi AM guys on 3885 and 3870 and thereabouts, who were building stations that sounded better than WGY and using advanced techniques like synchronous detection and the like to get fidelity and effectiveness simultaneously. Some of these were K3ZRF, W3DUQ, WA1EKV, WA1HLR, and hundreds of others. Many an engineering career was started because of the inspiration of this group. Quite a few of these guys are still on the air -- and manufacturers like Flex are now catering to the desires of hi-fi operators, which shows, in a sense, that they've been vindicated. These operators were able to capture the magic of radio -- and they met the challenge of really presenting their personalities and their ideas via good-fidelity radio in a way that could _never_ have been done over a telephone, while most ham stations were lucky to achieve telephone quality at best.
The day some retarded federal bureaucrat tells me that my friends and I can't run good broadcast-type audio on the amateur bands is the day I quit the service forever.
Let people decide their own limits. Most people are decent and won't step on existing QSOs, no matter what the mode. (And indecent people can always find a way to hurt others, no matter what the rules.) The wider-bandwidth guys generally never fire up their 7.5 kHz audio in the general band during crowded conditions. But on 75 during the day, or in the advanced or extra sections where there's plenty of room -- sure, why not?
160 meters has no sub-bands for different modes or bandwidths, and, with vanishingly small exceptions, everyone cooperates very well.
I got into amateur radio through SWLing in the late 1960s. The distorted, narrow signals that were touted as "state of the art" back then would never have attracted me. What interested me were the discussions of the mostly young, free-thinking, hi-fi AM guys on 3885 and 3870 and thereabouts, who were building stations that sounded better than WGY and using advanced techniques like synchronous detection and the like to get fidelity and effectiveness simultaneously. Some of these were K3ZRF, W3DUQ, WA1EKV, WA1HLR, and hundreds of others. Many an engineering career was started because of the inspiration of this group. Quite a few of these guys are still on the air -- and manufacturers like Flex are now catering to the desires of hi-fi operators, which shows, in a sense, that they've been vindicated. These operators were able to capture the magic of radio -- and they met the challenge of really presenting their personalities and their ideas via good-fidelity radio in a way that could _never_ have been done over a telephone, while most ham stations were lucky to achieve telephone quality at best.
The day some retarded federal bureaucrat tells me that my friends and I can't run good broadcast-type audio on the amateur bands is the day I quit the service forever.
If you limit that 'broadcast quality audio' on AM to the recognized signal bandwidth for AM mode then enjoy the fire out of it. If that 'broadcast quality audio' on AM means exceeding the recognized signal bandwidth for AM then I'll have to bid you goodbye, sorry to see you go. There are reasons for those signal bandwidth, good ones, especially as crowded as the bands get. The purpose of amateur radio is not experimentation and never has been. You are certainly allowed to experiment within bounds, but there are bounds. Get used to it. If you cause interference then you have no 'rights' to do whatever you want, that's in the rules too. Contrary to popular belief, anarchism isn't good and doesn't work.
- 'Doc
- 'Doc
What I want is what I've always had. Not anarchy. Freedom. You apparently want to take that away.
And that, sir, is the problem.
Every effort impose specific modulation bandwidth limits on amateur radio -- and there have been several dockets, starting in 1977 -- has failed so far. Every time, sir -- _every_ time -- the Commission's reason for rejecting the petitions has been to preserve amateur radio as an experimental service.
Of course, in these days of growing Stalinist-style government, perhaps people like you will eventually get your way. But you'll still be morally and technically wrong.
73!
some one needs to take his meds{Cry_river} or read part 97
Spurious emission. An emission, on frequencies outside
the necessary bandwidth of a transmission, the level of
which may be reduced without affecting the information being
transmitted.the necessary bandwidth of a transmission, the level of
which may be reduced without affecting the information being
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