Message-ID: <000201c0693e$e57f7c00$6729f7c2@oemcomputer>
From: "John Rabson" <word.factory@zetnet.co.uk>
To: rsgb_lf_group@blacksheep.org
References: <200012180256_MC2-BEEE-4A22@compuserve.com>
Subject: LF: Slow-Audio (was Re: DX Cluster spots for 10/17Dec at GB7DXM)
Date: Mon, 18 Dec 2000 22:01:03 -0000
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You might find this paper interesting:

Rabson, John and Hugo (1996) 'Some Experiments in Speech Bandwidth Reduction
', CREG Journal 24, pp3,6.

If you have difficulty getting hold of the article please let me know.

----- Original Message -----
From: Holger 'Geri' Kinzel, DK8KW <DK8KW@compuserve.com>
To: <rsgb_lf_group@blacksheep.org>
Sent: Monday, December 18, 2000 7:55 AM
Subject: LF: DX Cluster spots for 10/17Dec at GB7DXM


> Another thought: we in Germany are allowed to use any mode with a maximum
> bandwidth of 800Hz. I know that normal 2.1 kHz wide SSB signals havne been
> transmitted in the early days of LF in the UK. Has anyone ever thought of
> "Slow-Audio" instead of Slow-CW? My idea is to use an audio editing
program
> such as Cool Edit (available as shareware) and reduce the running speed,
so
> that a normal sharply filtered (the filter is a build-in feature of Cool
> Edit)  2.4 kHz audio signal is compressed into 800 Hz or an even smaller
> bandwidth. The same software could then be used to expand the signal again
> and make it audible. I plan to do some local testing (and yes: I will run
> those on reduced power using time slots when normally there is no traffic,
> I do not want to block the entire band with such a funny signal ...) to
see
> what can be achieved ...

73 de
John Rabson G3PAI