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Re: [RTTY] CQ WW RTTY Questions

To: "Jim Hooper" <k9qjs@icloud.com>, "RTTY Reflector" <rtty@contesting.com>
Subject: Re: [RTTY] CQ WW RTTY Questions
From: "Larry Gauthier \(K8UT\)" <K8UT@charter.net>
Reply-to: "Larry Gauthier \(K8UT\)" <k8ut@charter.net>
Date: Fri, 30 Sep 2016 08:36:14 -0400
List-post: <rtty@contesting.com">mailto:rtty@contesting.com>
Jim,

>I was thinking that it had to do with the number of transmitted shift commands

You've asked what may seem like a reasonable, simple question, but the answer 
is far from simple.

The background: In an effort to make RTTY reception more efficient, and to 
improve the probability of proper RTTY decoding, the convention for most hams 
is to enable a feature called Unshift On Space (UOS). UOS will force-unshift 
the decoding software to letters mode (LTRS) whenever a <space> is encountered 
in the inbound character stream, the assumption being that in the majority of 
instances a letter will be the character following the space.

Assuming UOS is universally enabled, a station transmitting an exchange of 
599<space>04<space>MI versus 599<space>MI<space>04 would send the same 
shift-to-numbers (NBRS) commands in either instance – because the transmitting 
station cannot assume the [NBRS] setting in the decoder survived the space 
between 599 and 04. This is one instance in which the assumption of “letters 
usually follow spaces” works against us.

599<space>[NBRS]04<space>[LTRS]MI 
599<space>[LTRS]MI<space>[NBRS]04

-larry (K8UT)
-----Original Message----- 
From: Jim Hooper
Sent: Friday, September 30, 2016 1:32 AM
To: rtty@contesting.com
Subject: [RTTY] CQ WW RTTY Questions

Relatively new to RTTY … a little less than a year.

A CW WW RTTY question: Why were some NA Stations sending 599 state zone, 
while I sent 599 zone state?   I would have thought that keeping the numbers 
together would be better for efficiency.

73,
Hoop
K9QJS
San Juan Island, WA
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