[RTTY] A challenge to RTTY operators!

Tyler Stewart k3mm at verizon.net
Fri Nov 16 12:36:37 EST 2007

I think part of the problem is that PSK software and practices havent been
optimized for contesting use.  Using an abbreviated character set would
help.  PSK software needs to be designed with a "contest mode" to make it
easier to use.  Automatically identifying and decoding the various version
of PSK would be another big plus.  Either that or we just have to accept
some version to be the defacto contest standard.

This will get operators on board, then you just have to get a major contest
sponsor to allow PSK and it'll all fall into place.



-----Original Message-----
From: rtty-bounces at contesting.com [mailto:rtty-bounces at contesting.com] On
Behalf Of Kok Chen
Sent: Thursday, November 15, 2007 12:52 PM
To: RTTY Reflector
Subject: Re: [RTTY] A challenge to RTTY operators!

On Nov 15, 2007, at 11/15    9:03 AM, Philip Leonard WVØT wrote:

> For me the "problem" with PSK31 for contesting is that it is slow  
> and so
> is hard to get a rhythm going.

One of the the reasons PSK31 feels slow is due to that 1/2 to 1  
second squelch tail at the end, where PSK31 goes into idle mode and  
then sends a short unmodulated carrier.  That is why you hear the  
vibrato stop and then followed by a beeeeep at the end of a PSK31  

It is easy to get rid of that tail when you are "contest mode."   A  
single line of code change ought to accomplish it.  RTTY contesters  
are used to seeing something like this anyway:

599 001 W7AY @#^D$&$*()))G

(that is why it is important to insert at least one space character  
after an exchange).

There is no reason not to get rid of the PSK31 tail when contesting.  
Of course it is no longer strictly obeying "true" PSK31, if you go by  
the specs for that mode.

Also, and I trust regular RTTY contesters already know this fact  
before participating in PSK contests, in PSK31 Varicode (and MFSK16  
Varicode, for that matter) lower cased characters take a shorter time  
to transmit than upper cased characters.

A lower case 'a' uses 6 bit periods (counting the sync bits) to  
transmit while an upper cased 'A' takes 9 bit periods (also counting  
the two sync bits).  Folks transmitting upper cased exchanges will be  
slower than those who use lower-cased only exchanges.

This, compared with the 7.4 to 7.5 bits in Baudot -- also counting  
the start and stop bits.  Some mechanical teletypes use 1.4 stop bits  
but most software modems transmit 1.5 stop bits.

Use some of these tricks, and your exchanges will be faster, and you  
won't even be accused of using a second radio :-).

Chen, W7AY

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