Port 30003 output discrepency

[gleff]

Hi,

I've just realized that MSG 6 from the RB port 30003 output is different to that of the competitor product.  I wrote a program in VB that parses the data and while watching the output from both devices I noticed that with the competitor product, MSG 6 *always* contains the Squawk code, and Altitude, whereby on the RB, MSG 6 shows only one or the other, but not both at the same time.

Has anyone else noticed this?  Bit of a pain because I'll have to try and make provisions for both devices now.  All other MSG's as far as I can tell are fine.

Here's an example.

The output from the RB
---------------------------
Begin,MSG,6,0,0,7C81CE,0,2010/02/13,19:40:46.419,2010/02/13,19:40:46.419,,26875,,,,,,,0,0,0,0,End
Begin,MSG,6,0,0,7C4832,0,2010/02/13,19:40:47.443,2010/02/13,19:40:47.443,,9050,,,,,,,0,0,0,0,End
Begin,MSG,6,0,0,7C6180,0,2010/02/13,19:40:47.437,2010/02/13,19:40:47.437,,,,,,,,3650,0,0,0,0,End
Begin,MSG,6,0,0,7C6180,0,2010/02/13,19:40:47.446,2010/02/13,19:40:47.446,,375,,,,,,,0,0,0,0,End
Begin,MSG,6,0,0,7C6D2B,0,2010/02/13,19:40:47.443,2010/02/13,19:40:47.443,,6050,,,,,,,0,0,0,0,End

In the above.. Lines 1,2,4,5 contain only altitude info and no squawk code
Line 3 contains the squawk code but no altitude

The output from the competitor product
---------------------------------------------
Begin,MSG,6,310,1248,7C6D7F,66981,2010/02/13,19:55:35.836,2010/02/13,19:55:36.507,,1925,,,,,,1437,0,0,0,0,End
Begin,MSG,6,310,368,7C6DB8,66979,2010/02/13,19:55:47.396,2010/02/13,19:55:47.662,,1300,,,,,,1165,0,0,0,0,End
Begin,MSG,6,310,368,7C6DB8,66979,2010/02/13,19:56:28.159,2010/02/13,19:56:28.221,,1025,,,,,,1165,0,0,0,0,End
Begin,MSG,6,310,1285,C81C3B,66984,2010/02/13,19:56:29.177,2010/02/13,19:56:29.235,,3725,,,,,,0237,0,0,0,0,End
Begin,MSG,6,310,155,7C6DB6,66982,2010/02/13,19:56:57.769,2010/02/13,19:56:58.642,,1900,,,,,,4214,0,0,0,0,End

In the above, all lines contain both altitude and squawk.

BTW.. Ignore the Begin and End parts of the output.  I added those for clarity.

Geoff

[DaveReid]

Strictly speaking, AirNav have got this one right IMHO.

Aircraft never send squawk and altitude in the same transmission. 

BaseStation, as far as I can see, combines the most recent DF4/DF20 (surveillance altitude) and DF5/DF21 (surveillance identity, i.e. squawk) transmissions when assembling a MSG Type 6, whereas RadarBox outputs a MSG 6 with only the contents of the most recent DF, either altitude or squawk.

So yes, RadarBox socket output isn't 100% compatible with BaseStation, and that may well break some add-on applications like yours, but it's closer to what's actually being sent by the aircraft.

[tarbat]

I guess this is an instance where SBS-1 Basestation output isn't 100% compatible with the Airnav Radarbox output ;)

[gleff]

That's cool.. Just wanted someone else to advise what the situation was.  Not laying blame anywhere.  I've already modified my program to suit both situations ;)

At least I know where we stand.

Thanks for the info.
Geoff

[DaveReid]

I guess this is an instance where SBS-1 Basestation output isn't 100% compatible with the Airnav Radarbox output ;)

But then again, I've never heard Kinetic claim that it was, only AirNav do !   :-)