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Re: [RTTY] ARRL attack on current RTTY users

To: RTTY Reflector <rtty@contesting.com>
Subject: Re: [RTTY] ARRL attack on current RTTY users
From: Don AA5AU <aa5au@bellsouth.net>
Reply-to: Don AA5AU <aa5au@bellsouth.net>
Date: Wed, 20 Nov 2013 15:58:15 -0800 (PST)
List-post: <rtty@contesting.com">mailto:rtty@contesting.com>
I'm trying to get a grasp on all this. I'm guessing that the ARRL has requested 
this change to 2.8 kHz to allow Pactor 4 which uses 2.4 kHz. Is this correct?

One Pactor 4 signal could wipe out all PSK, JT-65 and JT-9 signals on certain 
bands, all at the same time. Is this correct?

And who's pushing this from the commercial end? SCS? And Pactor 4 is used by 
the Maritime industry to pass email?

73, Don AA5AU



>________________________________
> From: Kok Chen <chen@mac.com>
>To: RTTY Reflector <rtty@contesting.com> 
>Sent: Wednesday, November 20, 2013 5:32 PM
>Subject: Re: [RTTY] ARRL attack on current RTTY users
> 
>
>
>On Nov 20, 2013, at 3:01 PM, Kai wrote:
>
>> I think that discussion should center around what the BW limit [should] be 
>> for digital signals. The answer will likely be something between 2200 Hz and 
>> 2800 Hz, because signals as wide as 2200 Hz are already permitted. It's good 
>> to discuss this.
>
>For conversational (keyboard, human-to-human) digital modes, 300 Hz to 500 Hz 
>is ample, and wide enough to use statistical detection methods that take 
>advantage of the frequency diversity aspects of selective fading on the HF 
>bands.
>
>300 Hz is also sufficient to do weak signal experiments to your heart's 
>content.
>
>The only reason anything wider is needed is to transmit massive amounts of 
>"data" or digital voice.
>
>Unless there is some enforceable rule that controls mutual interference 
>between conversational mode users and data mode users, the proposed change by 
>the ARRL only opens all of us to even worse QRM.  Even a 1 kHz signal in the 
>midst of an RTTY contest or pileup can completely ruin it.  That is what is so 
>wrong with the ARRL proposal.
>
>73
>Chen, W7AY
>
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