We only got down to half bandwidth, but...
----- Original Message -----
From: John Rabson <[email protected]>
To: <[email protected]>
Sent: Monday, December 18, 2000 10:01 PM
Subject: Slow-Audio (was Re: DX Cluster spots for 10/17Dec at GB7DXM)
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 <[email protected]>
To: <[email protected]>
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
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