Message-ID: <01d501c0a69b$569c4f00$5bb51bca@xtr743187>
From: "Vernall" <vernall@xtra.co.nz>
To: rsgb_lf_group@blacksheep.org
References: <14313.200103061746@gemini>
Subject: LF: Re: <TECH>Transcontinental modes - what next?
Date: Wed, 7 Mar 2001 13:12:00 +1300
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Dear LF Group,

Thanks to Jim M0BMU for generating a good discussion paper.  I have a few
comments:

I've taken the liberty of changing a word in the title from transatlantic to
transcontinental.

I'm don't see why the occupied bandwidth should be arbitrarily restricted to
10 Hz.  There could be something to gain from multicarriers, frequency
diversity or "spread spectrum".  Something like 50 Hz bandwidth may be a
better arbitrary upper cap to nominate for occupied bandwidth.

> One way to use longer dot lengths without increasing overall QSO
> time is to use multiple frequencies - for example, DFCW, VA3LK's
> 7-tone scheme, and VK2ZTO's one-tone-per character VFSKCW.

VFSKCW uses a sound card but otherwise is very similar to DFCW.  VK2ZTO's
other scheme is frequency difference keying (FDK) which would appear to
greatly reduce the need for high stability frequencies for transmitters,
receivers or sound cards.  I'm testing both VFSKCW and beta FDK.

I'm still in discovery mode with WOLF, and that certainly looks interesting.

73, Bob ZL2CA