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Re: [RTTY] To dash or not to dash - the bottom line

To: RTTY Reflector <rtty@contesting.com>
Subject: Re: [RTTY] To dash or not to dash - the bottom line
From: Kok Chen <chen@mac.com>
Date: Tue, 26 Jan 2010 13:19:08 -0800
List-post: <rtty@contesting.com">mailto:rtty@contesting.com>
On Jan 26, 2010, at 12:26 PM, Bill, W6WRT wrote:

> I'm not sure what you mean by "mixed shift" characters, but I will be
> glad to identify software which solves the whole problem neatly, and
> I'm sure the author would not be embarrassed at all.  :-)

Bill,

You reported a received exchange that printed as -QWE-QWE-QWE-QWE.

I can't think of any way that RTTY prints the above mixed shifting (LTRS 
shifted characters and FIGS shift characters mixed together without any spaces 
in between) unless extra FIGS and LTRS are intentionally sent.

If some software is printing that sequence on your machine, there is probably 
something wrong with it.

I.e., the only way the above can be received is that the sender  (whether it is 
USOS or non-USOS) has transmitted:

<FIGS>-<LTRS>QWE<FIGS>-<LTRS>QWE etc.

BTW, I just tested the K3 in FSK using the Morse paddle entry method to see if 
it uses USOS.

When you send "5<pause>5" in Morse from the CW paddle, cocoaModem (which has an 
option to display control characters) shows that the K3 generates 
"<figs>5<ltrs>[space]<figs>5".  Not really USOS.  

Basically, I think it generates a LTRS diddle when there is no immediate paddle 
activity, and by the time the pause is found to be long enough, it then finally 
sends a space (the system was already in LTRS shift at that point.  I.e., the 
K3 appears to send an extra LTRS if you send something like "599 123" when 
using the paddle in FSK.

I didn't check BPSK31 using a paddle on the K3, but I suspect that it also 
sends an extra idle Varicode before it sends a space character. You can think 
of the PSK idle and DominoEX beacon as having the same function as RTTY diddles 
(to keep the modulation active); in the case of DominoEX, the idle/diddle times 
are used to transmit a useful Beacon message).

And speaking of RTTY diddles, when I was experimenting with selectively faded 
RTTY signals, I had serendipitously discovered a very useful feature of diddles 
-- if you don't turn diddles on, a selective fade in the Space channel will 
cause the ATC to not properly track the slicer threshold when you are not 
typing.

73
Chen, W7AY

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