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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. AA6YQ

    AA6YQ XML Subscriber QRZ Page

    Automatic stations now use Pactor 3 to convey messages at 2700 bps. Yes, you could develop a 2800 hertz wide mode that works with most HF transceivers and delivers 75 bps -- but no network of automatic stations that provide message delivery would switch to a mode that slow, especially given their investment in Pactor 3 modems.

    The question is, with the 300 baud symbol rate limit intact but no bandwidth limit except that imposed by typical HF transceivers, can you design a mode that delivers significantly better throughput than 2700 bps? The answer is clearly "no". If it were technically and economically practical, WinLink would be using it.

    Even though there's now no regulatory bandwidth limit, for automatic stations, the 300 baud symbol rate limit combined with the electrical characteristics of most HF transceiver passbands yields a de facto 2200 hertz bandwidth limit.

    By removing the 300 baud symbol rate limit, the ARRL petition if adopted will eliminate this practical 2200 hertz bandwidth limit for automatic stations. Automatic stations would instead be limited by the proposed new 2800 hertz regulatory maximum. Automatic stations without busy frequency detectors would thus generate more interference than they do today.
  2. AA6YQ

    AA6YQ XML Subscriber QRZ Page

    That's also been my experience with attended stationd. However, it's not possible to contact an automatic station (lacking a busy frequency detector) that QRM's you. There is no message you can send it that will cause it to QSY or QRX.

    It's been a problem for years. No speculation is required to forecast that if automatic stations without busy frequency detectors can use wider signals than they use today, they will cause more interference than they do today.

    You continue to respond as if I were opposing elimination of the 300 baud symbol rate or the use of wider digital modes. I'm not. I only oppose taking those actions without simultaneously ensuring that automatic stations will not generate more interference than they already do today.

    The ostrich strategy never works...
  3. K2NCC

    K2NCC Ham Member QRZ Page

    Barely, if at all. I work everywhere I can and only occasionally do I suffer QRM from them. P4 boasts 5500bps or greater, and still fits in 2.4k.

    Even with QRM, it's 99% simple to just move. I get a lot more interference from narrow modes than I do wide.
  4. K2NCC

    K2NCC Ham Member QRZ Page

    I don't think you oppose elimination of the baud rate. I was speaking to people in general who do. I do however think "....more interference than they already do today" is more an impression than a fact. In my experience, interference of wide modes are almost non-existent. I use a lot of stations around the world, hours every day at my own, and no mode has caused me enough problems to ever want further regulation. I don't think we should be making rules around a possible problem that really isn't a problem today.

    Anyway, I'm off my soap-box for a while. I'll continue to follow the threads, but time to get back to playing radio... 73
    Last edited: Dec 20, 2013
  5. AA6YQ

    AA6YQ XML Subscriber QRZ Page

    Interference from automatic stations without busy frequency detectors has been a serious problem for years. Allowing the bandwidth of signals to increase from 2200 hertz to 2800 hertz can only make things worse.
  6. W4PG

    W4PG Super Moderator Lifetime Member 279 Volunteer Moderator Platinum Subscriber Life Member QRZ Page

    This is exactly like claiming that interference to the Maritime Mobile Net has been around for years. Seriously?? This is the best you can do??

    Gawd, this gave me a huge chuckle because your resistance to the change represents even less than the problem with 14.300. I mean REALLY!!!
  7. AA6YQ

    AA6YQ XML Subscriber QRZ Page

    Objecting to interference from automatic stations lacking busy frequency detectors is not "resistance to change" -- it's a refusal to accept shoddy engineering and operating practice that violates a fundamental precept of amateur radio: never transmit on a frequency without first verifying that it is clear.

    Interference from automatic digital stations has nothing whatsoever in common with "the problem with 14.300".
  8. N5CEY

    N5CEY Ham Member QRZ Page

    It seems to me that most of the resistance to this proposal is based on unintentional (sometimes intentional) qrm caused by "automatic" stations that do not "listen" before transmitting. This is already against the rules, so why are we not raising he** about the lack of enforcement of existing rules instead of crying that the new bandwidth will cause more? Well, the horse is out of the barn so we'd better put a bigger lock on it????? The damn horse is already gone.
  9. AA6YQ

    AA6YQ XML Subscriber QRZ Page

    Two reasons:

    1. The ARRL petition, if adopted will make things worse than they are now. It will enable automatic stations without busy frequency detectors to use even wider signals than they do today, causing even more interference.

    2. Eliminating the 300 baud HF symbol rate limit presents an opportunity to reduce the interference from automatic stations: automatic stations could be limited to 2200 hertz modes unless they incorporate automatic busy frequency detectors, which would entitle them to use 2800 hertz mode. This would incentivize automatic stations to incorporate busy frequency detectors, thereby reducing the interference they cause. The ARRL proposal would eliminate the symbol rate limit without the "busy frequency detector to gain access to wider modes" requirement -- foregoing this opportunity to get the horse back in the barn, and making it more difficult to do so in the future.
  10. N1EN

    N1EN Premium Subscriber QRZ Page

    Wouldn't complaining about such behavior when observed to the FCC or your friendly OO be a better way to address this, rather than campaigning against a proposed rulemaking that is only orthogonally related to the issue?
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