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SELCAL (Not receiving tones)


Lorenzo Francois
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Lorenzo Francois
Posted
Posted

Hello everyone,

 

Did not see any posts on this. I run the latest version of X-Pilot and started to do the Atlantic crossings, I gave the controller my SELCAL and I am not receiving the tones. I have the checkbox ticked to play SELCAL tones and when i connect I also put in the four letter code.

 

I did see an error when I checked the pre-filed with Simbreif that the code was different to when I connected with the Pilot client, is this hard coded once pre-filed?? Was that the error in not receiving the tones?

 

Please confirm to me what is the correct procedure when using x-pilot thanks.

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Robert Shearman Jr
Posted
Posted
Hello everyone,

 

Did not see any posts on this. I run the latest version of X-Pilot and started to do the Atlantic crossings, I gave the controller my SELCAL and I am not receiving the tones. I have the checkbox ticked to play SELCAL tones and when i connect I also put in the four letter code.

 

I did see an error when I checked the pre-filed with Simbreif that the code was different to when I connected with the Pilot client, is this hard coded once pre-filed?? Was that the error in not receiving the tones?

 

Please confirm to me what is the correct procedure when using x-pilot thanks.

I'm not sure about the pre-filing issue, but I'm pretty sure that the check box is to play the "default" SELCAL alert tone rather than the more realistic two-tone identification system that you would hear in the real world. So for added realism, leave that box UN-checked.

Cheers,
-R.

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Justin Shannon
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Posted

Make sure your flight plan remakes contains your SELCAL code. It should look something like SEL/ABCD.

Controller (C3), Los Angeles ARTCC
Developer: xPilot, vATIS

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Andreas Fuchs
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And make sure you choose a valid SELCAL-code.

 

A SELCAL code is made up of two pairs of letters (4 letters), and respects the following rules:

 

Only the letters A to S can be used.

The letters I, N and O are not allowed.

Duplicate letters in the same pair are not allowed (SEL/AABC or SEL/ABCC are not valid).

The same letter in both pairs is not allowed (SEL/ABAC is not valid).

The succeeding letter in the same pair must be higher than the preceeding one (SEL/ACDB is not valid).

 

https://www.avdelphi.com/selcal.html

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Justin Shannon
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Posted

Also note, xPilot will validate the SELCAL code you provide when connecting.

Controller (C3), Los Angeles ARTCC
Developer: xPilot, vATIS

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  • 2 years later...
Jonathan Pinkerton
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I'm guessing here, but here's what I come up with based on available evidence:

1) The SELCAL code has 16 (2^4) possible tones, which are represented for human-readability as A thru S minus I and O (so as not to be read as "one" or "zero"). I don't know why they skip N, does anyone know about this?

2) Each SELCAL code actually plays two notes to make a harmonic tone that is recognized by the receiver as the combination of two different audible frequencies. Two combinations are played one after the other. Because of this, a few things are obvious: First, you can't have the same tone twice in the same pair; that would be a single tone, and to avoid computer confusion, it must be told there's always two tones to recognize. Second, the "second letter in the pair can't be higher" simply because AB and BA played together would be identical. Third, you can't have the same letter in both pairs because otherwise the computer could give only 3 tones when in fact 4 were sent. (A SELCAL tone of ABCD could be misheard as ABAD and the computer would think this could be valid.)

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