Dave, That is a good input regarding AM, with voice modulation the amplitude rolls off quickly. Besides, no one of us surely would propose to legislate it away. In terms of bandwidth, I think the wider bandwidths are more efficient than 3 kHz bandwidth in that maybe 10 kHz bandwidth could accommodate, for example, 10 users with bursted traffic on a timeshare basis. Maybe some day all the digital users could be accommodated on one "channel" and alleviate the possible interference to voice modes. I am thinking of data, not voice. Digital voice is spectrum intensive. Still not HSMM but a thought for the future. Howie, K9KM -----Original Message----- From: Sumner, Dave, K1ZZ [mailto:dsumner@arrl.org] Sent: Thursday, May 26, 2005 1:52 PM To: arrl-odv Subject: [arrl-odv:12432] Re: Approaching BOD meeting Speaking only for myself, I can support maintaining AM as-is as a legacy mode because the full 9 kHz bandwidth is only occupied on peaks and because the amplitude at the edges is down quite a bit from the carrier level. A 9-kHz- wide digital signal is an entirely different animal. If you don't believe it, look for some broadcast DRM signals. The German transmitter on 3995 is over S9 at my location from before my sunset until European sunrise. It renders the entire upper 10 kHz of the band unusable by amateurs in the northeastern US -- it's quite a contrast to 40 meters, where we can slip in between the AM broadcast signals pretty well except when they're playing music. It may be that 3 kHz is a bit too restrictive -- I think the jury is still out on that -- but I don't think a single station should be allowed to use 2% of an entire band, which is what 9 or 10 kHz would represent. Dave K1ZZ -----Original Message----- From: Huntington Howard-CADV02 [mailto:Howard.Huntington@motorola.com] Sent: Tuesday, May 24, 2005 2:54 PM To: arrl-odv Subject: RE: [arrl-odv:12415] Re: Approaching BOD meeting Bob, Jim, and All, Our HSMM WG also have some issue with the maximum digital bandwidth within the proposal as it would stifle future development. One or two years ago they were looking for some bandwidths that would seem entirely impractical below 28 MHz. Last year I suggested to them to consider to target 10 or 20 kHz in a fixed band segment, in effect, a channel. They too have difficulty to understand why we support 9 kHz for DSB AM and at the same time, in their view, propose to stifle new development with similar bandwidth. Of course, none of us want complexity and inflexibility in the regulations. The premise of Novice Refarming supports digital allocations to some extent. If the proposal supports the beginning of new development today and some new technology gains wide acceptance, how long do we wait for further expansion? Part of the problem with wider bandwidth is we do not have a system waiting to go on the air or even a defined purpose to make us of the spectrum. One high speed digital channel at, for example, 3650 to 3660 kHz would provide for dial up speed at HF. It could coincide with 3 kHz maximum users of today's known modes. Compared to what we do at HF now, it will be blazing fast. A second channel at 7100 to 7110 would allow coverage with propagation variations. The 10 kHz bandwidth would be much more efficient than 3 kHz and would allow for OFDM with FEC. The opportunity is for better spectrum efficiency which the FCC wants. Imagine if today's Winlink users could be accommodated in 10 kHz using collision avoidance and short burst transmissions. That would reduce the apprehension of "unattended interference to SSB". Among the HSMM group, Walt DuBose, K5YFW, of the West Gulf Division is knowledgeable on this subject and has experience with various digital modes. This is not HSMM however it is close enough that we should consider the HSMM input. Howie, K9KM -----Original Message----- From: Sumner, Dave, K1ZZ [mailto:dsumner@arrl.org] Sent: Monday, May 23, 2005 8:16 PM To: arrl-odv Subject: [arrl-odv:12415] Re: Approaching BOD meeting I'm curious about the identity and credentials of your mystery member, Bob. He makes some good points but I'm uncomfortable with anonymity. Dave -----Original Message----- From: Vallio, Bob (Dir, Pacific) Sent: Tue 5/24/2005 2:08 AM To: arrl-odv Cc: Subject: Fwd: Approaching BOD meeting Comments from a member re signal bandwidth proposal: I have a few concerns about issues likely to come before the ARRL board that I'd like to present here. I was gratified to see many of my suggestions incorporated in the description of the revised proposal for regulation by bandwidth instead of by mode. However, the proposal described on the ARRL website still contains serious internal inconsistencies that detract from it's credibility. These inconsistencies also preclude some likely future technical developments. Unless and until these inconsistencies are satisfactorily resolved, the proposal should not be adopted. In July 2002, the ARRL Board of Directors directed that (Minute 64): "At the next practical opportunity the ARRL shall petition the FCC to revise Part 97 to regulate subbands by signal bandwidth instead of by mode." My concerns are that making a special dispensation for AM/ISB mode is inconsistent with this direction and not including wider bandwidth segments below the 10 meter band will preclude future technical developments. Petitioning the FCC with this inconsistency detracts from the credibility of the proposal. An approach that is consistent with the proposal would be to assign spectrum in additional HF bands for signals of 9 KHz or less bandwidth. However this is not the best approach to take in this case. The current proposal has no bandwidths greater than 3 KHz allocated below 10 meters. Given that one of the goals of this proposal is to preempt possible requests for future FCC action, it is inconsistent to preempt the future development of wider bandwidth modulation schemes, presumably digital. The advantages of wider bandwidth on HF include, for comparable modulation constellations, faster data rates. Given the apparent intent of the ARRL to provide the capability for emergency bridging of discontinuities in the Internet via WinLink2000 and the like, precluding the use of wider bandwidth signals is inconsistent. It is also inconsistent with the goals set in 97.1 of the commissions rules. In a similar context, HF modulation constellations of wider bandwidth can be more robust during periods of poor propagation than a narrower signal for the same effective data rate. While the modulation schemes are still to be developed, greater immunity to noise, multipath and interfering signals can be obtained at the cost of greater bandwidth. Presumably an adaptive scheme will be able to trade data rate for noise immunity over a continuum, depending on conditions. However this option will not be available if no accommodation for wider bandwidth signals is made in the HF bands, as is the case in the current proposal. In order to provide for these potential developments and also to provide for existing AM/DSB activity in a manner that is consistent with the remainder of the proposal, it is imperative that there be allocations for wider bandwidth signals on the HF bands below 10 meters. It seems wise to make these allocations as general as possible. I would suggest that 20 KHz of spectrum be allocated in the 160m, 80m, 40m and 20m bands for signals whose transmitted bandwidth shall not exceed 20 KHz. In other words, the widest allowed signal will just fill the subband. It seems prudent to select these subbands so that they include the frequencies currently used for AM/DSB "by gentlemens agreement". This will allow for three simultaneous AM/DSB QSOs (assuming that AM/DSB requires 6 KHz of bandwidth) and allow the future development of wider bandwidth digital HF signals. In summary, the revised proposal for regulation by bandwidth instead of by mode is internally inconsistent, inconsistent with the boards direction for its creation and less supportive of the goals in 97.1 of the FCC rules than it might be. These issues must be satisfactorily resolved before the proposal can be adopted by the board.