[RTTY] CQ WW RTTY Questions

[Larry Gauthier (K8UT)]

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 at 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
_______________________________________________
RTTY mailing list
RTTY at contesting.com
http://lists.contesting.com/mailman/listinfo/rtty