[RTTY] Great idea for the next 75 baud contest

[Don AA5AU]

I've noticed that 2Tone is far better at decoding at 75 baud than MMTTY. MMTTY doesn't work well at all at 75 baud.
73, Don AA5AU
 
      From: "Joe Subich, W4TV" <lists at subich.com>
 To: rtty at contesting.com 
 Sent: Monday, September 21, 2015 2:09 PM
 Subject: Re: [RTTY] Great idea for the next 75 baud contest
   

> The only way to prevent this is to create several new Profiles for
> 75 baud, each from a different existing base Profile with different
> taps and other settings. You will need to name them appropriately by
> the baseProfile settings - Flutter 75, FIR 75, etc.

The "problem" with this is that the settings for 45.45 baud are not
appropriate for 75 baud.  In particular, one will need more bandwidth
for 75 baud ... profiles like the AA6YQ-FIR-512, "hyper sensitive"
and "EU1SA" are too tight for 75 baud - particularly in the presence
of multipath and/or selective fading.

I would expect the difference between 2-Tone decoding and MMTTY to be
much more pronounced at 75 baud than at 45.45 baud.

73,

    ... Joe, W4TV


On 9/21/2015 11:14 AM, Gary Senesac wrote:
> Yeah but...
>
> When you create this new Profile in MMTTY you are doing more than just just changing the baud rate settings. Whatever Profile you use for your base settings will also be used for your new 75 baud Profile. If during the contest you decide that MMTTY isn't decoding well enough and want to try switching to a different Profile you will find yourself back to 45 baud!
>
> The only way to prevent this is to create several new Profiles for 75 baud, each from a different existing base Profile with different taps and other settings.  You will need to name them appropriately by the base Profile settings - Flutter 75, FIR 75, etc.
>
> This problem may be mitigated somewhat if you run multiple decode windows using either other instances of MMTTY set for 75 baud, or multiple 2Tone instances set to 75 baud with different decode parameters.
>
> Gary AL9A
> Sent from my Kindle HDX
>
_______________________________________________
RTTY mailing list
RTTY at contesting.com
http://lists.contesting.com/mailman/listinfo/rtty