[RTTY] VY2SS Cut Numbers in DL-DX

[Kok Chen]

On Jul 4, 2009, at 1:15 PM, Tim Goeppinger wrote:

> Why is it that everyone else can copy his cut numbers, except me
> and N6QQ?

Those are not cut numbers.  It is the result of one station (receiver)  
using USOS and the other station (sender) not using USOS.

Believe it or not, it is addressed in the "Digital Modes" chapter in  
the 2010 ARRL Handbook, but you need to wait for a while longer for it  
to be published :-).

In short, if the sender is not using USOS, the LTRS/FIGS state is  
unchanged after a space character.  So a 599 283 will be sent as  
599<shift>283.  However, if the receiver is using USOS, then it is  
decoded as the equivalent of 599<shift><LTRS>283.  Unfortunately,  
"283" under LTRS shift is decoded into "WIE," so you would print 599  
WIE.

When you are mostly sending numbers, USOS is of dubious use. In the  
case above, if the sender had used USOS, he would need to send an  
extra FIGS after the space.  USOS is useful for sending long text  
paragraphs that have mostly LTRS shifted characters -- any noise hit  
that causes an erroneous FIGS to be received will be corrected the  
next time a <space> is transmitted.

> I did not receive a decoder ring.

Sure you have (unless you are using a Dvorak keyboard).  But you might  
not realize that you have the decoder ring right at your fingertips.

If your contest program does not have a quick way to switch the  
display between the two shifts, just look at the numeric row of a  
QWERTY keyboard and the row of keys under it.  You will find that they  
have a direct relationship in Baudot.  I.e., Q=1, W=2, etc.

Hint: if you send 599-001 under RTTY, it will be received correctly by  
both USOS and non-USOS decoders.  It may not be pretty, but it works  
and requires no extraneous FIGS code to be sent.

73
Chen, W7AY