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  #11  
Old 05-18-2014, 02:13 PM
VHS VHS is offline
 
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Default Twist and shout

Respectfully, if you have any of our frequency agile transmitters, you should Enable Twist. The data consists of two tones, one at 1200 and one at 2200 Hertz. Radios and general physics tend to suppress higher frequency stuff at a higher rate than lower frequency stuff ( Stop me if I am getting too technical here) So our transmitters and everybody's receiver "hears" the lower tone better. This results in the low tone being received very well, and the high tone actually being "quieter" or lower in amplitude. When the deviation is set on a transmitter, its set at one frequency, because the actual deviation varies with frequency. Setting the transmitter to 3.5 KHZ deviation really means you are setting the 1200 Hertz tone to 3.5 KHZ deviation, and the higher frequency is attenuated. Based on the premise that there is no human or engineering problem that cannot be solved with brute force and ignorance, enabling Twist causes the 2200 Hertz tone to be broadcast at a higher amplitude than normal, or causing "pre-emphasis", which in nearly all cases will cause the two tones to be received and decoded at closer to equal amplitude, improving decodability.

73,

Allen
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  #12  
Old 05-18-2014, 02:24 PM
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Sam Buchanan Sam Buchanan is online now
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Quote:
Originally Posted by VHS View Post
Respectfully, if you have any of our frequency agile transmitters, you should Enable Twist. <snip>
Thanks for the clarification, Allen. My tracker doesn't have that option, and after reading the doc for the TinyTrak3Plus firmware it didn't seem it would apply to our application since I don't recall it ever being mentioned in regard to our aviation trackers. But I am very willing to defer to your recommendation.

Bruce, I didn't know you were using two configs, sounds like you are on top of it. Hope the new tweaks help.

See...that's what I get for trying to offer suggestions....I shall stay on the sidelines and watch with interest.
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Last edited by Sam Buchanan : 05-18-2014 at 02:31 PM.
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  #13  
Old 05-18-2014, 07:40 PM
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bruceh bruceh is offline
 
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Default Success!

I made the changes that Sam suggested and it seems to be working fine. Here is the track from my flight today.



Thanks a million!
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  #14  
Old 05-18-2014, 08:13 PM
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Nice investigation Bruce. Thanks for posting the update.

Allen, now I need to go see if I have "twist" set correctly.
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  #15  
Old 05-18-2014, 08:31 PM
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Sam Buchanan Sam Buchanan is online now
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Quote:
Originally Posted by bruceh View Post
I made the changes that Sam suggested and it seems to be working fine. Here is the track from my flight today.



Thanks a million!
Very nice track! You will enjoy your tracker.
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  #16  
Old 05-18-2014, 10:51 PM
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Default Trackky McTrackerson

Nice work Bruce! Great to get help from the pros here.

Sam and Allen keep us all "visible"....
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  #17  
Old 05-19-2014, 10:11 AM
pa38112 pa38112 is offline
 
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Allen - for clarification (because there seemed to be some back-and-forth) is this configuration the same as your recommendation, and is it how a new tracker will come configured for use in an airplane ?
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  #18  
Old 05-19-2014, 12:11 PM
VHS VHS is offline
 
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Default Defaults

Quote:
Originally Posted by pa38112 View Post
Allen - for clarification (because there seemed to be some back-and-forth) is this configuration the same as your recommendation, and is it how a new tracker will come configured for use in an airplane ?
No, your settings are very different. To start, you are using the mobile Digipath, of Wide1-1,Wide2-1, which I actually prefer since it works better on the ground. The default for an Aircraft would probably be set by Byon as WIDE2-1.

MIC-E should not really effect ground stations receiving you, but turning it off is a great way to debug the problems. One of the most Common TNC (Digipeater Controllers) has a known bug of delaying packets, and without a human readable time stamp, your ship may appear to be doing things that are physically impossible. Having a time stamp may not fix that, but it will clear up the problem.

Your Fast and Slow Smart Beaconing times are the same, so you may as well use just a timed transmission rate. Given your very wide digipath, once per minute is a bit fast to be considered polite for extended use, so we would set it at 120 second transmission intervals. Since you are selecting your config on the fly, so to speak, it would be more polite to switch to the narrower Digipath at altitude, and go wider at low altitude. This is actually a function we hope to make automatic in the next generation of software for the frequency agile products.

73,

Allen

Setting the Twist Enabled will always improve the transmission, although you may need to recalibrate the deviation control if you swap settings. Its designed to work with the Twist Enabled.
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