RTTY
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Re: [RTTY] RTTY

To: <rtty@contesting.com>
Subject: Re: [RTTY] RTTY
From: "Don Hill AA5AU" <aa5au@bellsouth.net>
Date: Mon, 21 Mar 2011 20:07:15 -0500
List-post: <rtty@contesting.com">mailto:rtty@contesting.com>
In MMTTY, there is both a "Character wait" and "Diddle wait" which make your 
transmission go out slower.  In the TX tab of MMTTY
Setup, there is a check box for "Disable Wait".  If it is not checked, then 
MMTTY uses the values as set in the two slider bars for
character wait and diddle wait.  Testing in FSK, revealed that indeed both of 
these slider settings change the "speed" at which the
"characters" or "diddles" are sent.  With both sliders all the way to the left, 
it appears is the same as checking the "Disable
Wait" check box.  As you move either slider to the right, the "speed" appears 
slower even though it's still decoded at 45.45 baud.
Here's what the MMTTY help file says:

"Transmit Wait Adjustment

There is a transmit wait, or delay, control, that appears by default as "Both 
Wait" at the far right of the transmit menu. The
slider to the right controls the amount of time (wait) between transmission of 
characters. Select one of four values by clicking the
label. 
  
Disable wait - Slider position does not matter, there is no wait. 
Char. wait - Delay character transmission. 
Diddle wait - Delay diddle character transmission. 
Both wait - Delay both character and diddle transmission. "


I don't see a "Both wait" option in version 1.68 so maybe that was left over 
from a previous version.  Elsewhere in the help file it
says something about using "wait" if there is a problem on a slower computer.  
I doubt anyone would have a problem these days and
everyone should disable wait.

73, Don AA5AU
http://www.aa5au.com
http://www.rttycontesting.com 

-----Original Message-----
From: rtty-bounces@contesting.com [mailto:rtty-bounces@contesting.com] On 
Behalf Of Al Kozakiewicz
Sent: Monday, March 21, 2011 7:11 PM
To: 'Ktfrog007@aol.com'; rtty@contesting.com
Subject: Re: [RTTY] RTTY

>What is the effect of the sound card clock adjustment? 

Nothing as far as data transmission/reception is concerned.  With ansynchronous 
communications. you need a clock at each end running
at (in the case of 45.5 baud, close to) the same frequency.  The leading edge 
of the start bit tells the receiver to start clocking
the data bits into individual registers.  The meaningful exchange is over once 
the agreed upon data and parity bits have been sent.
The stop bit(s) are a vestige of  the electro-mechanical days.  They provided a 
time slot to imprint the character.

If RTTY is "slow", it can only be due to more stop bits being sent in a 
character than necessary, or very inefficient shifting.
It's not due to the sender's bit clock being slow - that would just cause the 
transmission to be indecipherable.

Al
AB2ZY

-----Original Message-----
From: rtty-bounces@contesting.com [mailto:rtty-bounces@contesting.com] On 
Behalf Of Ktfrog007@aol.com
Sent: Monday, March 21, 2011 7:51 PM
To: rtty@contesting.com
Subject: Re: [RTTY] RTTY

Hi Don,
 
What is the effect of the sound card clock adjustment?  Is it related  to speed 
issues?See Calibrate the Sound Card in the Help file
and the Misc tab in MMTTY setup.  I've never understood what it is and what the 
adjustment does.
 
73,
Kermit, AB1J
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