[RTTY] 2 tone vs MMTTY

[David G3YYD]

John

Assuming you have the correct sound card set up and mark and space
frequencies. Then there is only one thing to change and that is the
propagation type. Two of the four types will cover most of the propagation
you will encounter and that is selective(e) [could not fit the "e" into the
buttons size] and the other is flutter.

Selective as my documentation explains - you did read it? - is when
multipath causes frequency selective fading of the tones so that one of the
tones at any instant in time will have a different amplitude to the other
tone. This will keep changing as the multiple paths change in amplitude and
phase. Flutter is for those occasions when the signal sounds, would you
believe, fluttery.

The spread setting is for those rare occasions when propagation modulates
the signal in the frequency domain and spreads the signal over a much wider
bandwidth. Typically found on trans polar paths and for those who live close
to or in the auroral zone. 

It should be noted that it is quite possible to have one QSO during which
selective and flutter will be better at different time in that QSO.

Now again in the documentation it will tell you not to not reduce the
receiver filtering to below 350Hz. Read the documents for the reason.

Also MMTTY AFC has a very nasty habit of wondering way off frequency. With
2Tone you have to be within 60Hz of the transmitted frequency. Very easy to
do just look at the lines on the spectrum display and make the small
vertical get close to or on the large vertical lines.

73 David G3YYD

-----Original Message-----
From: RTTY [mailto:rtty-bounces at contesting.com] On Behalf Of John Becker
Sent: 22 June 2014 19:41
To: rtty at contesting.com
Subject: Re: [RTTY] 2 tone vs MMTTY

I have both MMTTY and 2Tone running under WinWarbler, and I'm not seeing the
superior performance of 2Tone that so many other users are reporting. If
anything, MMTTY is decoding better for me. What settings should I be using
to optimize 2Tone? Thanks!

73,

John, K9MM

rtty-request at contesting.com wrote:
> In my experience the
> decoders I've tried fall thusly:
>
> 2Tone > TrueTTY > fldigi = MMVARI > MMTTY
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