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Re: [RTTY] Looking for an interface - a few simple requirements

To: RTTY Reflector <rtty@contesting.com>
Subject: Re: [RTTY] Looking for an interface - a few simple requirements
From: Kok Chen <chen@mac.com>
Date: Thu, 03 Oct 2013 19:30:40 -0700
List-post: <rtty@contesting.com">mailto:rtty@contesting.com>
On Oct 3, 2013, at 6:46 PM, Phil Sussman wrote:

> Meanwhile, RTTY is flexible, yet I believe AMTOR was more robust.
> I wonder if there ever was an AMTOR ARQ contest?

AMTOR FEC is really quite robust.  It is incorporated into SITOR-B in the 
commercial world, and still used by the Coast Guard for weather transmissions 
today.  W1AW however, has ceased Amtor bulletins.

Part of the reason for the robustness is that the mode is character synchronous 
(remember my earlier comment that RTTY with diddles can also be viewed as 
pseudo synchronous if the bit and character rates comply with standards?).  The 
other reason is there is character repetition after a small delay -- and thus 
countermeasuing QSB somewhat.

Unfortunately, the same FEC latency is also why AMTOR FEC is not really 
suitable for DXpeditions and contesting.  Not too long ago, you were explicitly 
allowed to use Amtor in the RTTY Roundup.

How many people remember that it is none other than Peter G3PLX (same bloke who 
created PSK31) who designed the Amtor standards?  And it is none other than 
David G3YYD (you know, that 2Tone guy?) who made the very first over the air 
Amtor QSO with Peter.

73
Chen, W7AY

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