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Date: Tue, 09 May 2000 16:46:52
To: rsgb_lf_group@blacksheep.org
From: "Rik Strobbe" <rik.strobbe@fys.kuleuven.ac.be>
Subject: Re: LF: DFCW  Parameters
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At 11:29 9/05/00 +0100, G4JNT wrote:
>What are the parameters for DFCW, or where are they specified. 
>
>I want to write some software to control my AD9850 DDS source (may be
>applicable to your 9832 source as well Dave) and might as well include
>this option.
>
>Andy G4JNT

Hello Andy,

DFCW is still a very experimental mode, so not very standardized yet.
Generaly accepted is that the higher frequency stands for 'dash' and the
lower for 'dot'. The frequency shift is dependent on the dot length.
For 3 seconds per dot (that has become a kind of informal standard) a shift
of 4Hz is used. A 1 second 'gap' is used to separate the elements (dots and
dashes) within a character, characters are separated by a gap of 1 dot
length, words by a gap of 2 dot lengths.

Marco (IK1ODO) has recently used DFCW at 40 seconds dotlength and with a
1Hz shift, his 10mW ERP signal was copied all over Europe.

Maybe this is the moment to create some 'temporary standard parameters' for
DFCW (but this shouldn't stop us from further experimenting).

I suggest 3 standard speeds :
* 3 sec./dot  : shift = 4Hz, gap = 1 sec.
* 10 sec. dot : shift = 2Hz, gap = 3 sec.
* 30 sec. dot : shift = 1Hz, gap = 10 sec.
Further I suggest to take the highest frequency for dash and lowest for
dot, a character separation of 1 dot length and a word separation of 2 dit
lengths.

Any other ideas or suggestions ?

73, Rik  ON7YD