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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