[RTTY] RTTY Digest, Vol 60, Issue 5

[John - AI4FR]

Hi Chen,
    Thank you for your thoughts on this one. I have had a number of simply 
wonderful people reply to this question. To answer your question, there is 
only one setting in MixW2 for USOS that I am aware of, either selected or 
not at all. I will give your suggestion a try and see what happens. I might 
even run it with an extra space after the 599 or callsign to see what works 
best. Thinking back, I have had three qso's that while in a ragchew if I 
ended a sentence with a period or used a comma, the other station received 
nothing but gibberish after that.

Thanks again
John / AI4FR



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http://www.webspawner.com/users/ai4fr/index.html

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Message: 3
Date: Sun, 2 Dec 2007 20:24:49 -0800
From: Kok Chen <chen at mac.com>
Subject: Re: [RTTY] USOS !) !) !) !)
To: RTTY Reflector <rtty at contesting.com>
Message-ID: <25A5C7A4-D58A-4E3B-9D99-36DC02318E54 at mac.com>
Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes

John,

I think the problem is that your software is making the assumption
that the other end is receiving using USOS.  So it does not send a
<LTRS> shift between 599 and FL, but instead depends on the receiver
to obey USOS and to automatically shift to <LTRS> after the space
between 599 and FL.

Remember that a SPACE can be sent in either FIGS of LTRS shift, so
there is no explicit LTRS shift that is sent between the 599 and FL.

I.e., I wouldn't be surprise that your output Baudot stream looks like
<5><9><9><SPACE><F><L>.  Which is received as "599 !)" by someone who
does not use USOS.

In my implementations of USOS, I have tried to make sure that what I
send can be read by both a USOS receiver and a non-USOS receiver.

I always prefer sending something like <5><9><9><SPACE><LTRS><F><L>.
The exchange is intact whether the receiver has USOS turned on or
not.  And "599 599" is sent as <5><9><9><SPACE><FIGS><5><9><9>.

If the software that you use is not open sourced and and there is no
way for you to selectively apply USOS to receive but not to transmit,
you can resort to sending "599-FL FL".  This will force your software
to send a <LTRS> after the dash.  The second SPACE will still provide
robustness to a USOS receiver, and you have used up only an extra 1/7
of a second.

Do not send 599-FL-FL because you will be sending oodles more
<FIGS>and <LTRS> and still end up not benefiting when the receiver is
on USOS.

73
Chen, W7AY



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