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VE2HAR > MT63 11.03.05 23:29l 56 Lines 1789 Bytes #-7343 (0) @ WW
BID : 33893SENTTO
Read: GUEST
Subj: Re: [MT63] 20 kHz wide Digital Proposal (Was: ARRL MUST GET
Path: DB0FHN<DB0THA<DB0ERF<DB0HGW<ON0DXC<ON0RET<DB0RES<ON0AR<VA2HAR<VE2HAR
Sent: 050311/2058z @:VE2HAR.#MTL.QC.CAN.NOAM Laval #:41397 $:33893sentto
On Fri, 2005-03-11 at 18:50, David Willmore wrote:
> Shannon said you can do that on a stateless channel with AWGN. HF is
> neither of those. In paths that are close to Shannons model--space--
> they do use wider bandwidths at constant power to get their signals
> through.
Please explain me why the general principle does not work on HF.
Clearly, adding redundancy and increasing bandwidth does work also
on HF even with fairly elementary techniques, like MT63 (which
by the way suffers from a rather bad crest factor problem, reducing
the available power, and still outperforms many other modes).
My main point is that there is an even greater misconception (ref.
your email to Karl) that narrow is better. It isn't, except for
the social/political aspect. I do realize that aspect is important,
but at the same time it makes me somewhat sad. We were supposed
to be the pioneers of communication, the knights of the ether.
At least that's what I was told in the ham radio course, at our
local club 20 odd years ago at age 12... Oh well... :) :)
--
Tomi Manninen / OH2BNS / KP20JF74
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