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Re: [RTTY] Multiple Decoders

To: Kok Chen <chen@mac.com>,RTTY Reflector <rtty@contesting.com>
Subject: Re: [RTTY] Multiple Decoders
From: Jerry Flanders <jeflanders@comcast.net>
Date: Wed, 01 Feb 2012 13:23:25 -0500
List-post: <rtty@contesting.com">mailto:rtty@contesting.com>
Port it to windows and I will send a check. Just tell me how much.

Jerry W4UK

At 01:09 PM 2/1/2012, Kok Chen wrote:

>On Feb 1, 2012, at 6:26 AM, Ed Muns wrote:
>
> > Many of us have been doing multiple decoders for years now, 
> particularly the
> > DXP38 plus multiple instances of MMTTY with different profiles.
>
>Some of us have used this for years now without even knowing they 
>are actually using multiple decoders :-P.
>
>The RTTY demodulator in cocoaModem consists of 9 separate RTTY 
>decoders.  Each one with a different ATC profile, although sharing 
>the same Mark and Space filters.  Instead of printing all 9 outputs, 
>a majority vote is performed and the most likely decoded Baudot 
>character is printed to the screen.
>
>All these 9 decoders work from a single audio stream (sound card) 
>from the receiver.
>
>So, it is like having 9 sub-modems, but you don't get to see all 9 
>outputs to decide for yourself which one is correctly printing.  You 
>only get to see what the software thinks is the correctly decoded 
>character.  Like democracies, the majority is not necessarily 
>correct, but they are correct more often than they are incorrect 
>(that is also why democracies work :-).
>
>In addition to that, cocoaModem has two of these built-in RTTY 
>demodulator sets.
>
>Each set is completely independent from the other, each with its own 
>waterfall, crossed ellipse indicator and modes (reverse, baud rate, 
>tone pair, etc).  And each one has its own Mark and Space filters. 
>These two "receivers" can be "connected" (menu selection) to two 
>different sound cards, or, if you like, can be connected to the same 
>sound card to give you 18 sub-modems, working off two different Mark 
>and Space filters.
>
>The two sound cards can be connected to two different receivers, 
>with the receivers coming from the same antenna, or coming from 
>different antennas for visual diversity reception (experimenting 
>with auto diversity decoding is in some planned future software :-).
>
>Almost always though, I connect the two modem sets to two channels 
>of a sound card that are connected to the main and sub-receiver of 
>my rig for split-DX chasing.  But other ops have the choice of 
>connecting both to the same sound card.
>
>73
>Chen, W7AY
>
>
>
>
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