In a message dated 8/12/07 8:47:15 AM Eastern Daylight Time, [EMAIL PROTECTED] writes:
> The SSB bandwidth 2007 realities, sound familiar. > In 1978 - max bandwith over telephonic modems, > and conditioned AT&T lines was like 6250 baud. > A "limit" everyone agreed. But was it a theoretical limit, or a practical limit? Or was it just a standard so that the industry could move forward? > > Then some clever soul or group, came up with > quadrature modulation - and rather quietly, > modems into the hot-copper telephone lines > of 52kbaud became a reality. > Hmm.... I seem to remember that there were a whole bunch of steps in there...14.4, 28.8, 33, and then two different flavors of "56K" modems... I remember my first serious PC dialing up AOL, and geting different connection speeds depending on the quality of the lines. My old house on RadioTelegraph Hill in Upper Darby had an old paper/lead cable, and the connect speed depended on the weather. When they finally replaced the cable, about 1998, it was much better. > Similiarly, perhaps HF comms SSB, needs to > rethink its SSB modulation approach, to allow wider > more naturally sounding voice comms, and still > not take up unnecessary bandwidth, beyone which > supposedly 2.7khz now consumes. Well, there's the NBVM idea of thirty years ago. Never really caught on, though. (when do we > > start talking about amplifiers?) > I suspect that a lot of the complaints about "SSB sounds bad" are really due to hearing distortion products in the audio, not limited bandwidth. > This topic, started as an attempt to learn > technically what ESSB was all about, in > its application to Amateur Radio. Never > learned anything, except everyone is > against it. Did you go to the websites mentioned here and read what they had to say? Here's a synopsis: Some folks don't like how typical amateur SSB sounds. They think the typical 2.1 to 2.7 kHz amateur SSB voice signal sounds bad. They think you need more audio bandwidth for a good sounding SSB voice signal. So they've modified their rigs to transmit and receive SSB voice at much greater bandwidths. 6 kHz and wider are commonly used. That means their signals take up much more of the band than a typical amateur SSB signal. Two, three, four or more times what typical ham SSB signals use. Other hams don't like them using so much of the band for one SSB voice signal. These other hams say it's good amateur practice not to use more of the band than needed for the mode in use. > > PLEASE close this topic, and wait out our > K3 purchase. I have no interest in bandwidth > debates or reasons, rather just what they > have been working on in SSB techniques. Other folks *do* have an interest. I'm > > sure the FCC, and ARRL will reign us in, if > we stray. > The ARRL can only advise what is and is not good practice. FCC has essentially said they don't really see the point of ESSB. The big threat to all of us is that we could wind up with more-restrictive regulations that we don't like, because of the actions of a few. 73 de Jim, N2EY ************************************** Get a sneak peek of the all-new AOL at http://discover.aol.com/memed/aolcom30tour _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
