[RTTY] bartg sprint 75 sv1dpi

[Peter Laws]

On Mon, Sep 19, 2011 at 16:04, Peter Laws <plaws at plaws.net> wrote:
> On Mon, Sep 19, 2011 at 12:52, Kok Chen <chen at mac.com> wrote:
>
>> If the modem that is optimized for 45.45 baud does not change the internal filter for 75 baud operation, the SNR does not go up.  However, something even worse happens since a 75 baud signal will cause some pretty severe inter-symbol interference (a signal QRM'ing itself, so to speak :-).  You can even see this effect when using 45.45 baud, if you use a crystal filter in a rig that is too narrow, without also having an appropriate shape for binary 45.45 baud data.
>>
>
>
> I wondered about this when I was trying to copy K9MUG/4.  All I did
> was set MMTTY to "decode" 45.45 bauds.  I didn't fiddle with any of

I meant 75 bauds!!



> the other 10,000 settings on the config screen (for fear I'd delete
> half the internet if I did).
>
> I'm guessing that what I really need is a 75-baud "profile" in MMTTY
> that optimizes things for that speed (along the lines of 23-Hz shift
> profile that's distributed with the software).
>
> Anyone done that that is willing to share?
>
>
> --
> Peter Laws | N5UWY | plaws plaws net | Travel by Train!
>



-- 
Peter Laws | N5UWY | plaws plaws net | Travel by Train!