Thanks, John. I stand corrected. It has been quite a few years since
that time and my recollection was that the argument was that the signal
lasted such a short time on any one frequency that it would not create
significant QRM, but that also may have been a misunderstanding on my
part, or simply not what was proposed.
73 - Skip KH6TY
John B. Stephensen wrote:
The HSMM working group never proposed the use of spread spectrum. It
was interested in getting the maximum data rate into limited
bandwidths. SS does the opposite of what the HSMM WG was interested
in. It spreads limited amounts of data over the maximum bandwidth.
The actual proposal was to create small segments in the 80, 40, 20 and
15 meter bands for emissions up to 16 kHz wide -- matching what
existed in the 10 meter band but on a much smaller scale. Many of us
wanted that limited to 9 kHz -- the same as the ARRL allowed for AM.
The goal was to preserve the priveledges that currently exist in the
phone/image segments (AM equivalent bandwidth) as the ARRL was
shrinking bandwidths in the RTTY/data segments (currently unlimited
bandwidth).
73,
John
KD6OZH
----- Original Message -----
*From:* KH6TY <mailto:kh...@comcast.net>
*To:* digitalradio@yahoogroups.com
<mailto:digitalradio@yahoogroups.com>
*Sent:* Saturday, March 06, 2010 14:01 UTC
*Subject:* Re: [digitalradio] A question about spread spectrum
The other possible problem is "wide-spreading" spread spectrum.
There was a failed attempt about 5 years ago by the ARRL HSMM
(High Speed Multi-Media) proponents to allow spread spectrum on
the HF bands with the argument that the signal is spread so
widely, each carrier appears at any given frequency only a short
time, so it would not significantly interfere with other users of
the frequency, and could, for example, be allowed to cover the
entire 20m band.
