Russ, At least in the Seattle area all-HD tests, the interference was much greater. One would expect the opposite, since the hash would be in the center of the main frequency, but the hash was maybe two or three times more intense than in the hybrid mode. Thus, 1360 in Tacoma was mixed with noticeable HD hash during the KRKO tests, although none is heard normally. The area's 1400 is a much weaker station, and it stood no chance against the HD onslaught. Incidentally, I'm not local to KRKO. It's a strong signal which can be heard in HD during the day, but not a full-quieting local. Same for 1520, which is in Snohomish County (I'm in King County.) Based on the tests I've heard, the hash from a completely local HD station would be so noisy in analog that it could persuade analog AM listeners to turn it off rather than even look around for other stations on the dial. If the AM band were a mix of HD-only and analog signals, it would be almost like having a bunch of vacuum cleaners running, each taking up a total of 60kHz. I think that's the most graphic way I can explain what it sounded like in analog. But even in an all-HD situation, power would likely need to drop considerably to keep HD-only stations from interfering with each other. I can't see how all-HD signals would work compatibly in either a mixed or total HD mode. It was that bad. -- Rick
-----Original Message----- From: IRCA [mailto:irca-boun...@hard-core-dx.com] On Behalf Of Russ Edmunds Sent: Friday, April 22, 2016 1:51 PM To: Mailing list for the International Radio Club of America <irca@hard-core-dx.com> Subject: Re: [IRCA] All-Digital AM Co-Channel Lab Test Results Unveiled Bottom line, this is, after all, the NAB, and their mantra is "More, more more stations". I would expect their rsults to understate the potential issues. That said, a straight up digital signal would occupy the center of the main channel - where today's analog signal is. And the digital signal should occupy less bandwidth by itself and a typical analog signal. The IBOC hybrid mode has the analog signal at center and the two hybrid digital signals on either side. Thus the combined IBOC signal occupies substantially more bandwidth than a single digital signal. That's why Chuck said ( or one reason why ) it wasn't comparable. But that also doesn't predict much else. Russ Edmunds 15 mi NW Phila Grid FN20id <wb2...@gmail.com> AM: Modified Sony ICF2010's (2) barefoot w/whip FM: Yamaha T-80 & T-85, each w/ Conrad RDS Decoder; Onkyo T-450RDS; Tecsun PL-310 ( 2); modified Sony ICF2010 w/APS9B @ 15'; Grundig G8 w/whip; modified Sony ICF2010 w/whip On Fri, Apr 22, 2016 at 12:15 PM, Nick Hall-Patch <n...@ieee.org> wrote: > It's quite easy to correlate Chuck. Just add ignorance and stir. I > don't believe they actually said anything much about the digital > signal, so assumption of all digital IBOC can reasonably be added to > that mix. (other details about demodulation of the analog signal are > also missing) > > Audio examples would be nice, and might help to convince the doubters. > > > http://www.radiomagonline.com/deep-dig/0005/broadcast-engineering-conf > erence-radio-technology-forum-sessions/37600 > offers descriptions of the conference sessions, but I haven't been > able to quickly track down any more detailed results than what Dennis linked to. > > http://diymedia.net/old/stuff/AM_IBOC_Test.pdf has a nice graphic on > the first page which I assume is what Chuck is alluding to in terms of the > difference between present IBOC and all-digital IBOC. Is that the case > Chuck? If so, perhaps you could suggest a listening test that could > be done with today's systems (thereby saving me the trouble of doing it > incorrectly)? Those secondary OFDM subcarriers already sound pretty nasty > on KRKO's signal this morning, and they would be stronger in the > digital only version. > > best wishes, > > Nick > > > > > > > At 05:03 22-04-16, you wrote: > >> ... >> >> I don't see how you can correlate hybrid IBOC to all digital IBOC. >> What you hear with KRKO/KAST is different from what you will hear >> with all digital as the power spectrum and subcarrier levels are >> vastly different. >> >> Chuck >> ________________________________________ >> From: IRCA <irca-boun...@hard-core-dx.com> on behalf of Nick >> Hall-Patch < n...@ieee.org> >> Sent: Friday, April 22, 2016 4:51 AM >> To: Mailing list for the International Radio Club of America >> Subject: Re: [IRCA] All-Digital AM Co-Channel Lab Test Results >> Unveiled >> >> I presume "D/U" abbreviation in this piece refers to "desired / >> undesired"? >> >> I wonder if someone recorded audio from those tests, rather than just >> tossing dB's around? I have a recording of KAST-1370 from this >> morning that says otherwise, with KRKO-1380 IBOC sidebands about 25dB >> down and....welll, KAST is readable, but I wouldn't say it's lacking >> interference. The noise becomes really dominant if KAST is less >> than ~15dB above the IBOC level. >> >> best wishes, >> >> Nick >> >> >> >> >> At 21:05 21-04-16, you wrote: >> >http://www.radioworld.com/article/all-digital-am-co-channel-lab-tes >> t-results-unveiled/278670 >> > >> >Sent from my iPad >> >_______________________________________________ >> >IRCA mailing list >> >IRCA@hard-core-dx.com >> >http://montreal.kotalampi.com/mailman/listinfo/irca >> > >> >Be sure to register now for the Joint DX Convention Kansas City, >> >September 9 to 11. Hotel space is filling up. >> >Registration info: >> >http://www.nrcdxas.org >> > >> > >> >Opinions expressed in messages on this mailing list are those of the >> >original contributors and do not necessarily reflect the opinion of >> >the IRCA, its editors, publishing staff, or officers >> > >> >For more information: http://www.ircaonline.org >> > >> >To Post a message: irca@hard-core-dx.com >> >> >> _______________________________________________ >> IRCA mailing list >> IRCA@hard-core-dx.com >> http://montreal.kotalampi.com/mailman/listinfo/irca >> >> Be sure to register now for the Joint DX Convention Kansas City, >> September 9 to 11. Hotel space is filling up. >> Registration info: >> http://www.nrcdxas.org >> >> >> Opinions expressed in messages on this mailing list are those of the >> original contributors and do not necessarily reflect the opinion of >> the IRCA, its editors, publishing staff, or officers >> >> For more information: http://www.ircaonline.org >> >> To Post a message: irca@hard-core-dx.com >> >> _______________________________________________ >> IRCA mailing list >> IRCA@hard-core-dx.com >> http://montreal.kotalampi.com/mailman/listinfo/irca >> >> Be sure to register now for the Joint DX Convention Kansas City, >> September 9 to 11. Hotel space is filling up. >> Registration info: >> http://www.nrcdxas.org >> >> >> Opinions expressed in messages on this mailing list are those of the >> original contributors and do not necessarily reflect the opinion of >> the IRCA, its editors, publishing staff, or officers >> >> For more information: http://www.ircaonline.org >> >> To Post a message: irca@hard-core-dx.com >> > > > _______________________________________________ > IRCA mailing list > IRCA@hard-core-dx.com > http://montreal.kotalampi.com/mailman/listinfo/irca > > Be sure to register now for the Joint DX Convention Kansas City, > September 9 to 11. Hotel space is filling up. > Registration info: > http://www.nrcdxas.org > > > Opinions expressed in messages on this mailing list are those of the > original contributors and do not necessarily reflect the opinion of > the IRCA, its editors, publishing staff, or officers > > For more information: http://www.ircaonline.org > > To Post a message: irca@hard-core-dx.com > > _______________________________________________ IRCA mailing list IRCA@hard-core-dx.com http://montreal.kotalampi.com/mailman/listinfo/irca Be sure to register now for the Joint DX Convention Kansas City, September 9 to 11. Hotel space is filling up. Registration info: http://www.nrcdxas.org Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers For more information: http://www.ircaonline.org To Post a message: irca@hard-core-dx.com _______________________________________________ IRCA mailing list IRCA@hard-core-dx.com http://montreal.kotalampi.com/mailman/listinfo/irca Be sure to register now for the Joint DX Convention Kansas City, September 9 to 11. Hotel space is filling up. Registration info: http://www.nrcdxas.org Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers For more information: http://www.ircaonline.org To Post a message: irca@hard-core-dx.com
