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[RTTY] MMTTY Sound Card Calibration

To: rtty@contesting.com
Subject: [RTTY] MMTTY Sound Card Calibration
From: Ktfrog007@aol.com
Date: Tue, 22 Mar 2011 19:14:24 -0400 (EDT)
List-post: <rtty@contesting.com">mailto:rtty@contesting.com>
Thanks, Don.  Today I did this calibration on both of my RTTY  computers.  
One was right on 11025 while the other had to be raised to  11100.
 
The calibration is a pain in the butt because the instructions are so  
abstruse.  It's actually kind of fun if you do it this way instead:
 
1. Click Option | Setup | Misc tab
2. Click the Adj. button
3. Tune your radio to the exact frequency of one  of the standard stations.
4. The waterfall display will show one (8000 or 6000 Hz) or two (11025  Hz) 
lines of marks (vertical or slanted) of the station's 1 second tick sound  
bursts.  The goal is to get the tick lines exactly vertical:
   - If they slant like a forward slash ( / ), raise your clock  speed.
   - If they slant like a back slash ( \ ), lower your clock  speed.
5. Continue these adjustments until the incoming tick line goes  vertical.  
You can right click on the green line and drag it to the tick  line to use 
as a visual aid if you wish.
6. When you're happy ;-)), click OK to leave the setup display and save the 
 new value.
7. Restart MMTTY for the new clock value to take effect.
 
That's it.  Forget all the yellow line stuff, that's for  highways.
 
This gives you something to do while the screen is filling up.  By the  
time it's full, you should have the incoming portion of the line vertical.
 
73,
Kermit, AB1J
 
 
 
 
In a message dated 3/22/2011 12:02:10 A.M. GMT Standard Time,  
aa5au@bellsouth.net writes:

No, the  sound card clock adjustment has to do with frequency error.  For 
example,  using the default 11025 on my laptop caused
signals that were tuned to 2125  Hz Mark to show off frequency in the 
tuning displays.  I fixed this by  changing the clock setting in
MMTTY to 12000.  The calibration is a  pain in the butt, but once you 
figure it out, it's not too bad.

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

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