Why (and How) You Should Urge the FCC to Reject the ARRL’s Symbol Rate Petition

Discussion in 'Working Different Modes' started by AA6YQ, Dec 7, 2013.

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  1. K2NCC

    K2NCC Ham Member QRZ Page

    all this complaining about possible QRM, which will exist even if the rules don't, still overlooks the trade-off of data rate for bandwidth.

    please do not ask to reduce our currently unlimited bandwidth for digital modes.

    at the very least, digital should be allowed the same as voice or any other mode.

    there's plenty of room on the HF bands for all of us. don't limit our future abilities!
  2. AA6YQ

    AA6YQ XML Subscriber QRZ Page

    The ARRL petition if adopted will specify a maximum bandwidth of 2800 hertz for digital modes on HF bands. For automatic stations, this is a significant increase from the 2200 hertz "practical limit" established by the combination of the 300 baud HF symbol rate limit and the characteristics of most HF transceiver passbands.

    I don't object to allowing digital modes to use 2800 hertz signals, but I strongly object to allowing a current problem to become worse -- which the ARRL petition in its current form would do by allowing automatic stations without busy frequency detectors to use even wider signals than they do now, causing even more interference.

    Eliminating the 300 baud HF symbol rate limit provides an opportunity to reduce the interference caused by automatic stations: require them to incorporate a busy frequency detector if they want to use a mode wider than 2200 hertz. Approving the ARRL petition would make it much harder to employ this incentive later (it'd be a "take-away" rather than an inducement) -- another reason why this petition should be rejected.


    Dave, AA6YQ
  3. K2NCC

    K2NCC Ham Member QRZ Page

    I've made my FCC comment, and read many. I can't help but think:

    1. Some people are agreeing to the proposal just because they're ARRL supporters. [like voting for an NRA lobby gun Bill you haven't studied]
    2. Folks that don't use digital modes are making comments of which they have little experience. [to me, loss of bandwidth feels as bad as losing one of our bands]
    3. Those that complain about digital QRM actually have no chronic issues with such interference. [you probably "suffer" more during a contest]
    4. There are hams eager for more than 300 baud and think 2.8k will be more than enough for what we currently do. [someday we may have, i.e., the tech for HD video on HF!]
    5. Or they just hate digital and think Pactor should be at the bottom of the ocean. [although at 2.4k, takes less room than your SSB signal]

    I've mentioned before, as this subject now has many threads, if we cut ourselves off to less than 3k for digital modes, we're going to regret it later. There are modes in the .gov, .mil and business world now that we might someday get our hands on. Many are very large, 5k, some even 10k wide. Which is still smaller than some AM bandwidths.

    There are literally 100s, if not 1000s of digital modes on HF. I have one book on my shelf with 300 described in it.

    Don't sweat the occasional QRM possibilities. We've been working around each other for decades, we can handle this. It's not as if everyone is going to go out and buy a $2000 modem for one mode.
  4. AA6YQ

    AA6YQ XML Subscriber QRZ Page

    You should try making digital mode QSOs between 10,140 and 10,150 sometime. I've lost QSOs to QRM from automatic Pactor stations there, as well as on 40m; I have an SCS PTC-IIe that can decode Pactor, so I'm not guessing.

    There is no contest QRM on 30m or the other WARC bands.

    A fundamental principle of amateur radio is that one should never transmit on a frequency that is in use. Automatic stations without busy frequency detectors violate this principle. The ARRL petition, if adopted, will allow them to do so with wider signals than they do today, increasing the interference rate. That's why the FCC should reject this petition.


    Dave, AA6YQ
  5. N1EN

    N1EN Premium Subscriber QRZ Page

    They're already allowed to to run wide automatic signals today. The only thing that changes is that they can send at a higher baud.

    Non-automated wide signals are technically allowed (in the US) all the way down to the bottom of the bands on HF. The proposal doesn't change that either.

    Now, I have been stepped on my Pactor and Winmor signals before. But I've also been stepped on by inconsiderate CW, SSB, RTTY, PSK, etc. operators (or perhaps operators who couldn't hear me despite them being S9+ to me). I'd see that as a different kind of problem, and not necessarily one that's aggravated by the proposal.
  6. AA6YQ

    AA6YQ XML Subscriber QRZ Page

    The 300 baud symbol rate in combination with the properties of most HF transceiver passbands limits automatic stations to a bandwidth of 2200 hertz; Pactor 3 is the widest mode in frequent use by automatic stations; its bandwidth is 2200 hertz. The ARRL petition, if adopted, would enable automatic stations to use 2800 hertz modes. Thus the QRM from automatic stations without busy frequency detectors will increase if the ARRL petition is adopted.


    Dave, AA6YQ
  7. K2NCC

    K2NCC Ham Member QRZ Page

    I spend a lot of time on 30. I just left 30M before reading yours, and had the same happen to me there just minutes ago.

    I can appreciate your angst, but I gotta say, "So?". Sometimes one doesn't make the log, or requires me to repeat or move.

    Yup. Wide modes might be more of a concern if 30M was your only band. Heck 50Hz can be a nuisance on that slice of RF. But is the occasional QRM worth reducing the ENTIRE (US) amateur community's abilities and potential?

    But Dave, who really knows? That's a prediction at best. We are NOT going to suddenly see our bands fill up with a swarm p4 dragon signals across the bands just because they can. Too expensive for one thing. I think most digital mode users will stick to narrow modes. They're inclined to squeeze out as much as they can in as little space as possible. (sample on my zed bio)

    Sometimes wide modes don't have a detection scheme enabled, or just can't hear you, but it's no worse than any other QRM. Spin the dial. Send them an email. Learn the mode and talk back.

    I would not say that's the reason, but we do agree on the preferred demise of RM-11708.

    I like a lot of things in this Proceeding, but for the flaw of limiting bandwidth. I like the rate increase. I'm NOT a fan of sub-bands, so wide digi being able to go into CW or Phone is fine with me. ANY mode should be allowed ANY spot on the band, IMNSHO. We can co-ordinate amongst ourselves fine enough that we don't need the feds telling us where to park.

    If it moves forward, everyone under FCC will be limited to 2.8k digi on HF. Probably for the rest of our lives.
  8. AA6YQ

    AA6YQ XML Subscriber QRZ Page

    Having one's QSO wiped out by an automatic station that starts up without first checking to see that its frequency is clear, and won't respond to any form of QRX signal is simply unacceptable! It's a violation of fundamental amateur radio principle and practice. Five years ago, defenders of automatic operation would characterize this as an existential tradeoff between allowing and not allowing automatic operation. Today, DSP algorithms that use a soundcard to detect CW, PSK, RTTY, and Pactor activity on a frequency are freely available; there's simply no excuse for not incorporating them in automatic stations, but the owners of many automatic stations refuse to do so -- as your recent experience on 30m demonstrates.

    I'm not arguing against wide modes. I'm arguing against allowing automatic stations without busy frequency detectors to use wider modes than they can use today -- which is what will happen if the ARRL petition is approved.

    Limiting automatic stations without busy frequency detectors to 2200 hertz or less would not "reduce the ENTIRE (US) amateur community's abilities and potential". Neither would requiring automatic stations using bandwidths greater than 2200 hertz to incorporate busy frequency detectors.

    Eliminating the 300 baud symbol rate restriction will enable the development of fast, wide modes for message passing that do not require multiple sub-carriers (OFDM) and sophisticated encoding schemes, as Pactor 3 was forced to do to maximize transfer rate. A fast laptop with a soundcard will be all that's necessary; that will be quite a bit less expensive that what's required now, not more expensive. If the operators of automatic stations weren't intent on fully exploiting the ability to employ 2800 hertz modes, they wouldn't be ardently campaigning for adoption of the ARRL petition's.

    That's not correct. If I'm QRM'd by an attended station, its operator will generally respond to my QRL and politely QSY. An automatic station will not do that. QRM from an automatic station is far worse than from an attended station.

    Since automatic operation was made legal, thousands of such emails have been sent by digital mode operators whose QSOs have been broken up by automatic stations; they've had no effect.

    There is no command you can send an automatic station that will cause it to QSY or QRX -- even if you have the correct modem available (which I do).
  9. K2NCC

    K2NCC Ham Member QRZ Page

    I can't argue with you there. I've always disagreed with any station that was unmanned, legal or not. If your station can QRM (assuming our ears would hear it) being on auto, it shouldn't be on auto.

    As far as cross-mode QRM, I really believe it's unlikely to be any worse. Either way, it should be up to us to figure out where we want to build our sandboxes. We and perhaps the ARRL can co-ordinate without making it a law to do so. We have enough of that already. The FCC allowing ANY mode to pull up anchor and move around is a good thing. LESS likely to be QRM methinks.

    I can't speak for what's available to auto-stations and refusals. I would have to ask them. Every time I've contacted a chronically QRM'ing station (in a NICE way!), they've always moved or simply couldn't hear what I did.

    It's speculation as to if it'll be a problem. If I were in charge, I'd resolve that issue by requiring auto-stations to be manned and in control. even beacons. Like the rest of us have to.

    However, that "than they can use today" is the catch... technology is advancing fast. A decade or two from now, I predict we'll be wishing we had ordered a bigger slice of pie.

    99% of what I do is 2k or less, so I'm not going to suffer a loss of QSOs if this is granted. But we still shouldn't limit our possibilities. This will be a hard bell to un-ring later.

    Then that's where our opinions differ most. Approval of this into regs would limit HF digital to 2.8k. As the FCC already said, and now becoming one of my favorite quotes;
    "We also believe that imposing a maximum bandwidth limitation on data emissions would result in a loss of flexibility to develop and improve technologies as licensees’ operating interests change,new technologies are incorporated, and frequency bands are reallocated." [DA 08-1082]

    I personally like, from the same document, "Our rules do not specifically limit the permissible bandwidth for RTTY and data emissions in the amateur HF bands."

    Why would we ever give that up? You guys that want this to pass with the 2.8k limit have no vision! 8)

    I am all for that! There's a lot addressed in this RM, certain to continue being forum-fodder.

    Did the ARRL send out any questionnaires to members of what they thought about it before submitting?

    In that case, I would just change freqs, perhaps send a email, or use it as a good excuse to hang out w/the XYL for a while. :)
  10. N1EN

    N1EN Premium Subscriber QRZ Page

    This statement makes absolutely no sense.

    I'll bet you anything that I can transmit a 2.8kHz wide 75bps signal on any legal frequency you name.
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