SDRTrunk

whitfords · Jan 4, 2015

Hi folks,
I hope you can help me. I am trying to decode the ANI and GPS location in the data tail at the end of transmissions. The transmissions are from TAIT 8000 series radios that leave a FFSK 1200 or 2400 tail after the transmission. I have tried using sdrtrunk with a dongle but no luck. Here are some links to the data I am trying to decode. All four files have the same data, but I increased the volume on it as it came through a bit low. Files are .wav and .mp3 depending on what you prefer.

Thanks in advance to those that can assist in pointing me in the right direction.

http://www.filedropper.com/ffskvolumeincrease
http://www.filedropper.com/ffskoriginal
http://www.filedropper.com/ffskoriginal_1
http://www.filedropper.com/ffskvolumeincrease_1

DSheirer · Jan 4, 2015

whitfords said:
Hi folks,
I hope you can help me. I am trying to decode the ANI and GPS location in the data tail at the end of transmissions. The transmissions are from TAIT 8000 series radios that leave a FFSK 1200 or 2400 tail after the transmission. I have tried using sdrtrunk with a dongle but no luck. Here are some links to the data I am trying to decode. All four files have the same data, but I increased the volume on it as it came through a bit low. Files are .wav and .mp3 depending on what you prefer.

Thanks in advance to those that can assist in pointing me in the right direction.

http://www.filedropper.com/ffskvolumeincrease
http://www.filedropper.com/ffskoriginal
http://www.filedropper.com/ffskoriginal_1
http://www.filedropper.com/ffskvolumeincrease_1

Can you post those files to my dropbox and I'll see if I can add decoder support for the format. Please post the .wav format files.

https://www.dropbox.com/sh/l3f34ana5imulgl/AACOq9MBx9SDzQclFNEu67tIa?dl=0

(I tried your download links and they keep timing out).

Denny

whitfords · Jan 4, 2015

Hi Denny and thanks. Not sure why it is timing out - I clicked on your Dropbox link but it wants me to sign in. Sorry if it is a dumb question (I do use Dropbox myself) but how do I drop files into your dropbox? Cheers

DSheirer · Jan 4, 2015

whitfords said:
Hi Denny and thanks. Not sure why it is timing out - I clicked on your Dropbox link but it wants me to sign in. Sorry if it is a dumb question (I do use Dropbox myself) but how do I drop files into your dropbox? Cheers

I think you can just drag the files from your file explorer and drop them on the webpage from the link.

whitfords · Jan 4, 2015

I have put them in my Dropbox. Hopefully this share link will work https://www.dropbox.com/sh/gljkb1pz4n3ue0c/AABO9l5CW-esKGRsShpFiYN5a?dl=0

DSheirer · Jan 4, 2015

whitfords said:
I have put them in my Dropbox. Hopefully this share link will work https://www.dropbox.com/sh/gljkb1pz4n3ue0c/AABO9l5CW-esKGRsShpFiYN5a?dl=0

That worked. I have horrible DSL internet ... one of the downfalls of living in the country.

Do the ANI signal bursts occur that often, or did you stitch together several instances in the .wav recording?

whitfords · Jan 4, 2015

I stitched together a bunch of them. Currently the FPP has it set that to transmit the data on the tail 15 minutes or later after the last instance. e.g First transmission will have it and any subsequent ones won't until 15 mins passes, then the next transmission will have it.

DSheirer · Jan 5, 2015

whitfords said:
I stitched together a bunch of them. Currently the FPP has it set that to transmit the data on the tail 15 minutes or later after the last instance. e.g First transmission will have it and any subsequent ones won't until 15 mins passes, then the next transmission will have it.

I added a new auxiliary decoder to sdrtrunk to decode these Tait 1200-baud FFSK ANI and GPS bursts. I think I've figured out the beginning of the ANI unit identifier, and if I'm correct, this is a goofy protocol - everything is sent as 8-bit ascii digits. It seems to follow the Tait CCDI protocol, or at least the few rare descriptions of CCDI that I could find.

There are two distinct message types in the example that you posted, each with a unique 16-bit sync pattern.

Here's what I have so far for the unit identifier. The first two digits are the size of the message in bytes. I haven't figured out anything beyond the second set of bit revs yet.

Code:

                                               0        8        0        0        2        6        5        0        1        9    crc           
09:47:32.948 TAIT:1010 0001010011011100 00000000 00001000 00110000 00110000 00110010 00110110 00110101 00110000 00110001 00111001 0011101110111110 1010101010101010 00111011001010000000000000011110011100110000000000011110 00000000 00011001 00110000 00110000 00110000 00110000 00110000 00110000 00110000 00110000 10000000 01010000 00011001 10010100 11010010 10010011 10010011 00011011 01000010 10011001 10110001 01011100 00010011 10010011100001000000010010010101111010111111110111100000000011110110
                                               0        8        0        0        2        6        5        0        1        2   
09:48:39.468 TAIT:1010 0001010011011100 00000000 00001000 00110000 00110000 00110010 00110110 00110101 00110000 00110001 00110010 1000101000111000 1010101010101010 00111011001010000000000000011110011100110000000000011110000000000001100100110000001100000011000000110000001100000011000000110000001100001000000001010000000100101001010110010001100000001001001100011011001010010110001010110001010111000000011000010011100001000000000000000000010010001110001101100010100011101110
                                               0        8        0        0        0        1        2        3        4        5    
09:47:49.038 TAIT:1010 0001010011011100 00000000 00001000 00110000 00110000 00110000 00110001 00110010 00110011 00110100 00110101 1110001011100010 1010101010101010 00111011001010000000000000011110011100110000000000011110000000000001100100110000001100000011000000110000001100000011000000110000001100001000000000100011010001011001010011010100110000001001001100011011001010010110001010110001010111000000011000100001100001000000000000000000110111010011011111100001000000010000

Denny

whitfords · Jan 5, 2015

Do you want any more examples? I am told they have a unique identifier (ANI) followed by NMEA data as the GPS location.

whitfords · Jan 5, 2015

Actually the beginning numbers look similar to the selcall numbers of the callers, so I assume that is what they used to identify the transmitting unit.

DSheirer · Jan 5, 2015

whitfords said:
Do you want any more examples? I am told they have a unique identifier (ANI) followed by NMEA data as the GPS location.

Yes, more samples would be good.

I'll post a test build tomorrow that you can use to decode. Then, if you could log the decoded messages and send me the log. I think I can figure out the GPS string with enough examples.

whitfords · Jan 5, 2015

Cool, no worries. thanks

DSheirer · Jan 6, 2015

I posted a new test build (sdrtrunk_20150106_2024_lj1200_and_tait_test.zip) that includes the experimental Tait 1200 FFSK auxiliary decoder. You can use the decoder by choosing NBFM as your primary decoder and placing a check next to Tait-1200 in the auxiliary decoder tab.

Also, in the Log tab, please check the Decoded Messages option to save any messages that get decoded. If you could send those logs to me, it will help in figuring out the rest of the messages.

The decoder produces two messages: A & B. Message A will parse the 8-digit from identifier and the 8-digit to identifier, or at least I hope that's what they are. If you discover any more of the field values, let me know and I'll add them to the parser.

With no error checking, you will likely get noise (garbage) decodes.

There may be additional message types like Short Data Messages. If they have their own sync pattern, then the current decoder will not decode them. If you can get a recording, I can figure out the sync pattern and add support for those as well.

Denny

whitfords · Jan 7, 2015

Thanks!!! I'll run it tonight. I'll also edit some more data bursts and let you know when they are in the dropbox

whitfords · Jan 7, 2015

G'day,
Log in the dropbox from this afternoon's traffic.
Thanks

whitfords · Jan 7, 2015

.....and some more data audio recorded from today is in the dropbox....

whitfords · Jan 8, 2015

Hey, will this Tait document about their data help? http://www.rotronix.co.nz/PDF files/MM8100-00-00-441.pdf

DSheirer · Jan 8, 2015

whitfords said:
Hey, will this Tait document about their data help? http://www.rotronix.co.nz/PDF files/MM8100-00-00-441.pdf

Yes, I saw that on Monday and the message format is similar. I think I've got the GPS format figured out and hope to have something for you to try this weekend.

Do you have the recording from yesterday in wave format? MP3 format corrupts the signal.

whitfords · Jan 8, 2015

Ahhhh bugger. I meant to save it wav. I will record some traffic today and edit it this arvo and upload...

whitfords · Jan 9, 2015

I have placed some more examples in the dropbox

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