Message-ID: <3937B8C4.3B437859@usa.net>
Date: Fri, 02 Jun 2000 15:38:12 +0200
From: "Alberto di Bene" <dibene@usa.net>
Organization: Undisclosed
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To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: Slow CW vs. BPSK. & Computer modes
References: <3617AC3245C2D1118A840000F805359C01AB8C85@pdw-mercury-1.dera.gov.uk>
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Talbot Andrew wrote:

> [snip]
> There seems to be no appreciation on this newsgroup of the real value of
> coherent detection - that is, having phase information available when
> the signal is decoded and coherently locking to the signal carrier and
> bit  timing.   Simple theory, as I covered in a previous email, shows
> mathematically the considerable theoretical advantage of coherent
> detection over non coherent, there is no dispute about this.
> [snip]

Andy,
                 from a theoretical point of view you are damn right. But I am
not so sure that LF/HF propagation can preserve phase coherence and
with it the decoding gain achieved with coherent detection, unless you are
willing to use some extra bandwidth to transmit phase information.
But, then, I am not a propagation expert, so my comments stop here.

73,
Alberto   I2PHD