C++ implementation of a burst OQPSK demodulator for C-band Aero signals

JAERO v1.0.4 demodulating and decoding T packets from the C-band

JAERO v1.0.4 demodulating and decoding T packets from the C-band

Well it took about hundred more hours of work but I have finally managed to put together a burst OQPSK demodulator for the 10500bps Aero signals found on the C-band. For this I took my initial Matlab design, the recordings I had, the Part III – Inmarsat and MTSAT manual, and went from there.

Generally the implementation followed my initial design but there were a few changes and many details to work out converting it into a C++ implementation. Of the changes I made, I changed some of the burst timing detector. This seemed to perform just as well as the one in the design stage, while the one in the design stage didn’t seem to work very well at all in C++; I’m not really sure why. For carrier frequency estimate I removed the large FFT and instead use two medium sized FFTs instead of the two small FFTs.

With Matlab generally you have all the time in the world as everything is just a vector that is already prefilled. With a real-time application samples come in one at a time and they are usually processed one by one as they come in, this meant the C++ implementation ended up having a lot of delay lines to compensate for all the delays caused by the processing of the samples by various stages. A block diagram of the burst demodulator can be seen in the following figure.

Block diagram of the 10.5kbps burst demodulator used in JAERO

Block diagram of the 10.5kbps burst demodulator used in JAERO

Delay lines like the 288T and the 587T are to compensate for the burst time estimation block, the peak searching algorithm and the Trident buffer. These delay lines change if you were to alter any of these items.

The thing I hadn’t really figured out in my initial design was how to produce an estimate of symbol timing and to give it to the demodulator. Unlike a normal continuous demodulator, a burst demodulator requires symbol timing very early on, you just don’t have the time to slowly adapt over a second. For Aero R packets the whole transmission is over in about 80 ms. The modulated section of the preamble is designed to allow for rapid estimation of symbol timing. In this modulated section one arm is held constant while the other arm flips back and forth each sample, this can be seen in the following figure where “symbol osc” is written.

Real and Imaginary arms of the 10.5kbps R/T preamble

Real and Imaginary arms of the 10.5kbps R/T preamble

A symbol has a period of T seconds so the oscillations produced by this arm are at 1/(2T) Hz. Being OQPSK correct symbol timing is a bit sneaky, you have to sample at 2/T Hz but only one of the arms is valid for each sample time, and what is valid alternates between one and the other. So it’s not just good enough to sample at the correct time you also have to sample the correct arm. This is one trap I fell into. My initial implementation was not reliable and half of the time I would appear to get perfect symbol timing and produce a constellation that looked like noise. This was caused by sampling at the right time but the wrong arm. The reason why this never happens for the continuous OQPSK demodulator for JAERO is that if the wrong arm is being sampled the carrier tracking rotates the whole constellation by 90° which flips the two arms causing the right arm to be sampled at the right time. However, for a 80 ms packet this process is too slow and that’s why I got a constellation that looked like noise. The solution to this problem can be seen in the bottom quarter of the block diagram of the burst demodulator.

The multiplying thing with tanh on it causes the constellation during the modulated section of the preamble to align in the real direction. The T/2 delay causes the oscillation to become a rotation, and the rest is just a PLL (Phase locked loop). This is phase linked to a faster oscillator to produce correct sampling time. The thing I have called Demux alternatively selects between the real and imaginary arms, if it is sampling the wrong arm the slower 1/(2T) oscillator knows this and resets the Demux to sample the correct arm. That was missing piece of the puzzle for me. This means the demodulator adapts to the symbol timing during the modulated section of the preamble and also resolves this which arm to sample ambiguity.

This burst demodulator calculates accurately burst arrival time to within a few samples of its actual value independently of the frequency of the burst. It then calculates the frequency of the burst to within say about 10Hz ish along with its phase. It uses these estimates to acquire symbol timing as well as the which arm to sample ambiguity. After about 50ms the preamble is completed and standard carrier and symbol timing tracking are used.

P C R and T

P C R and T channels are mentioned in the Part III – Inmarsat and MTSAT manual. Although the manual calls them channels they are really just different types of packets.

The P packets are sent continuously and these are the ones that everyone has been receiving and decoding so readily using JAERO on the L band.

I know little about the C packets but these packets contain audio and can also be easily received easily on the L band. Where 8.4kbps seems to be a common rate.

R and T packets are the burst transmission packets that I’ve been working on demodulating. These are the ones that can be received using a C-band antenna. Currently I only know three people who have received such signals including myself. Such signals require a high gain dish but otherwise are not too difficult to receive. The smallest dish used so far has been 1.8 m in diameter. As well as demodulation, decoding is required to make sense of all the ones and zeros received.

R packets are small consisting of 320 bits. These packets are randomly sent by the airplanes in timeslots that my coincide with other airplanes hence packets may collide. These packets seem to be mainly for acknowledgments and various other control activity.

T packets are variable in length from 512 bits to 6080 bits. These packets are also given timeslots to be sent but the timeslots are allocated by the GES to avoid packet collision. These packets are the juicy ones and contain the long ACARS messages with positional information.

To decode any of these packets the first thing you do is put the received data into a matrix of a certain size and read back in a certain way to deinterleave them. For the P and R packets the manual tells you how many columns and how many rows you are supposed to use, for the T packets it’s a different story, they don’t. For the T packets they say you use 64 rows but the number of columns can be anywhere from 8 to 29 columns in increments of three. From what I could tell there wasn’t any simple way you could tell how many columns were required. So my method to solve this problem was, as the data grew ever bigger, put the data into ever bigger matrices and attempt to decode every matrix as if it was valid until either it had more than 29 columns or the CRCs (cyclic redundancy checks) were all valid. If all the CRCs were valid I had the correct number of columns, otherwise either the number of columns were invalid or the packet was erroneous. There is the added complication that you have to do a lot to check if the CRCs are right, as well as putting them into a deinterlever you have to run them through a viterbi decoder, descrambler and finally calculate the CRCs. The following screenshot shows the basics of what is needed to calculate the column size. One convenient feature though is once you’ve calculated the correct column size you have also decoded the data.

Code snippet for finding interleaver size of T packets

Code snippet for finding interleaver size of T packets

You might have noticed that I’m also checking for R packets, that’s because I don’t know whether or not you are tuned into a T channel or an R channel frequency.

Just like for the P packets on the L band, it seems different frequencies have different GES allocations like the following figure shows.

Different frequencies are used for different GESes

Different frequencies are used for different GESes

T channel data

Here is an audio recording of one of the GES82 T channels from my dish with my bad set up. I start with this as a demonstration audio as it’s about as bad a quality as you would want to have. My LNB is not a PLL one the frequency is all over the place and the signal level is low. During making this recording I had to adjust the frequency of the radio just to keep the audio in the bandpass. Another reason is if you use demodulator and decode the signal you see the following two packets.

13:03:29 20-02-16 AES:780783 GES:82 2 .B-6533 ! 10 3 AIRBUS A330-243 AIR CHINA

    M03ACA1338POS190827,N 25.337,E113.473,1040,  464875,,,37092,52000

13:03:51 20-02-16 AES:AA7238 GES:82 2 .N772UA ! B6 0 BOEING 777-222 UNITED AIRLINES

    F30AUA0873/OAKODYA.ADS.N772UA070FDC9B2BD3C9C41A2F1D0D11C88B282289C405401423D3241D8A7F800E7B98DCBFFC0F7871A2FFFC1051B25E4E7AC7

The first packet is obviously a position location as “N 25.337,E113.473” obviously means 25.337° North and 113.473° East and is where the plane should be. Also note “POS” is in the packet which presumably means position. I think these packets go with the one seen on the L band that have the format like “#MDREQPOS037B” which presumably means we requests a position (REQPOS) from the flight control computer (#MD) or perhaps we acknowledge the position as sent by the flight control computer. “M03ACA1338POS190827,N 25.337,E113.473,1040, 464875,,,37092,52000” I assume is how the flight control computer responds or initiates the conversation. So that was easy, however, the format most positions seem to be given in matches that of the second format.

The second format always has ADS (Automatic Dependent Surveillance) written in it which presumably means ADS-C. Some things are obvious with the format but others such as how the the latitude and longitude values are encoded are not so apparent. Just as with the first format there seems to be a conversation that takes place between some computer on the ground and the flight computer. Perhaps on the L band you seem packets that look like “OAKODYA.ADS.80104S01910B” these packets obviously part of a conversation. This packet that comes from the ground computer is easier and is clearly asking for the position location or more likely acknowledging the position location that was just sent from the flight computer. My guess as to how such a packet is constructed is as follows.

OAKODYA         ADNS address (the message comes from Oakland)
.ADS            it's an ADS message
.80104S         the plane's Registration number
01              presumably 01==ACK (*acknowledge*) 00==NAK (*not acknowledged*)
910B            presumably a 16 bit CRC

The ADNS address I found in a flight operations manual. ADNS might stand for “ARINC Data Network Service” but I’m not too sure.

Splitting up the ADS packet that came from the airplane the same way results in the following.

F3              Flight computer capabilities?
0A              (LF)
UA0873          Flight number
/               (next section)
OAKODYA         ADNS address
.ADS            it's an ADS message
.N772UA         the plane's Registration number
07              packet type
0FDC9B2BD3C9C41A2F1D0D11C88B282289C405401423D3241D8A7F800E7B98DCBFFC0F7871A2FFFC1051B25E4E
7AC7            16bit CRC

Using a longer and better quality recording of a T channel from Europe I exclusively saw packets of the second format, the ADS format. However, it was still only a couple of minutes long. In fact there was very little other traffic apart from these kinds of packets.

I couldn’t find much information about this type of packet on the web so to understand a little more about the ADS packet format I put together a whole lot of payloads of them in rows like as follows from the European recording and removed the odd ones that didn’t quite match the others.


14244487554D88CA0B981D0D2444471C71C8CA0BD2244446E38E48CA0097F3
142CCC671C6D484D4BA01D0D2D82DEE38E484D082E2DAD56B05B084D00997C
14244487554D88CA0B981D0D2444471C71C8CA0BD2244446E38E48CA0097F3                          #1
072444AF551308CA0BCC1D0C10C234CB48201041A43E240D2444471C71C8CA0BC9244446E38E48CA00AA20  #2
0725B86F9194484D0C461F0C0815F9E608200D25B6778E41084D00B7266C675563488B80104230FE407BEE
072450FF829408CA0C529E0C0815F2C478200D244447555548CA09DA2444471C71C9088010332A9E28F709
0725C6476E74C84CCC689F0C2CC376D338200D25B36755554908453425B3671C71C908401041297E3EDB66
1425B0AF1C6908CA0C761D0D25B05EE38E48CA0AF924D5EEC9C408CA00B3FA
071D1BD72421888C0CE41D0D1C71CF1C71C88B82BB18E3970000088B8066B1
141A7FDE779B49858CF21F0D1957CE69178A028634191E6666668A0280BFED
071633EF48F849470CF41D0D13E9471C71C9470FB8105B0EE38E494700A2A9
07214E8F803588C9CD341D0C197275D32820102E28DE220D20B60F555548CA0A931C71CF1C71C8CA0076A8
07239E4F2862C908CD5B9D0C0464B3CF88200D2391471C71C908827E23913EE38649088010661F7DF85459
07278BDF2A1749C3CD941D0C508676D75D60105C237DB40D27D2871C71C9C402C928888EE38E49C400D54F
072D35070156080E8DA01D0C0815F90C78200D2D82DEE38E480E83FF2DAD56B05B080E80102BA13E249F8E

Almost all the packet types seem to be 0x07 and 0x14. The 23rd column was the only nibble that was always the same so obviously around about that area there must be a boundary. Also quite apparent was the repetition in some of the packets, for example take what I have called #1 and #2, they can be written as follows.

#1
14                              Packet type 
2444 87554D88 CA0B 981D         Payload 1
0D                              0 Boundary marker with the next nibble to align
2444 471C71C8 CA0B              Payload 2
D2                                        
2444 46E38E48 CA00                        
97F3                            16bit CRC

#2
07                              Packet type
2444 AF551308 CA0B CC1D         Payload 1
0C                              Boundary marker with the next nibble to align
10C234CB48201041A43E240D        Payload 2
2444 471C71C8 CA0B
C9
2444 46E38E48 CA00
AA20                            16bit CRC

It gives you an idea of where possible boundaries might be. So if you want a fun activity to do you can figure out how these packets are constructed and how the position information is contained within them.

Finally, for completeness, here is what the R packets sound like.

Real live testing

Until now I had been just dealing with recordings that either I made while other people made before I was able to demodulator and decode these signals. So today with a little more clement weather I took out the deck chair, put the new demodulator on the laptop, and spent some time receiving C-band signals and decoding them on-the-fly. I used the same trick to align the dish with the GPS antenna as I did when I first went hunting for C-band Aero signals.

This time I took a little time to have a look around and too. When demodulating a T channel a signal suddenly appeared and stayed on for a few minutes, looking at it it had the right bandwidth for an 8.4kbps C channel signal so maybe it was some voice traffic. You can see this in the following figure.

GES 82 T channel with a possible voice channel from a plane

GES 82 T channel (right) with a possible voice channel from a plane (left)

Most of the stuff on the C-band did not stay there for very long and almost all of it was bursty in nature. I found one exception to the rule which was the signal in the following figure.

Useful almost constant pilot for tuning dish

Useful almost constant pilot for tuning dish

Most of the time it would just be a constant frequency but occasionally it would quickly do an oscillation back and forth. As it was generally a constant frequency it turned out to be a handy signal to align the dish better.

I tuned into both T GES channels I could find for the satellite I was using as well as having a quick look at the some of the more plentiful R channels. The following logs shows what I got from the satellite during the live test. I just realized now that the time on the laptop was 12 hours and four-minute slow, so “06:32:13 20-02-16” means “18:36:13 20-02-16” NZDT. This means it was about 1 hour fast from UTC time.

06:45:47 20-02-16 AES:78037B GES:82 2 .B-6093 ! BA 6 AIRBUS A330-243 AIR CHINA

    J20ACA0194/BNECAYA.AT1.B-609361045C5C001287

06:45:48 20-02-16 AES:A2A38E GES:82 2 .N26952 ! B6 5 BOEING 787-9 DREAMLINER UNITED AIRLINES

    L90AUA0099/OAKODYA.ADS.N269520AFA4B63F46548C9AE458F9E6E

06:45:49 20-02-16 AES:AABD7F GES:82 2 .N791UA ! B6 2 BOEING 777-222 UNITED AIRLINES

    F85AUA0840/NANCDYA.ADS.N791UA07FC025BD1FD080EAE6D1D0DFE923BD842880E8649038C1400114856400E0DC0FF80040F0DC1A400041007263EF015F6

06:45:57 20-02-16 AES:7C4924 GES:82 2 .VH-OQE ! B6 1 AIRBUS A380-842 QANTAS

    J31AQF0011/NANCDYA.ADS.VH-OQE07FC6F6BF066888B6E681D0E07C103FFFC0F0711A27FFC101AAADECA0DFCE913F230088B81440074AC0332C88B80C932

06:46:09 20-02-16 AES:AABD7F GES:82 2 .N791UA ! B6 4 BOEING 777-222 UNITED AIRLINES

    F86AUA0840/NANCDYA.ADS.N791UA03024C42

06:46:09 20-02-16 AES:C023AA GES:82 2 .C-FNND ! BA 8 BOEING 777-233 AIR CANADA

    L44AAC0034/BNECAYA.AT1.C-FNND67925C730065AB

06:46:10 20-02-16 AES:A2A38E GES:82 2 .N26952 ! B6 7 BOEING 787-9 DREAMLINER UNITED AIRLINES

    L91AUA0099/NANCDYA.ADS.N2695203022A41

06:47:17 20-02-16 AES:C023AA GES:82 2 .C-FNND ! BA 9 BOEING 777-233 AIR CANADA

    L45AAC0034/BNECAYA.AT1.C-FNND28172E827258E921

06:49:53 20-02-16 AES:AABD7F GES:82 2 .N791UA ! B6 7 BOEING 777-222 UNITED AIRLINES

    F88AUA0840/NANCDYA.ADS.N791UA0AFC53B3D408480EB23D1D42C0

06:50:04 20-02-16 AES:7C6C73 GES:82 2 .VH-VPH ! B6 0 BOEING 777-3ZG VIRGIN AUSTRALIA

    F82AVA0007/OAKODYA.ADS.VH-VPH14FF9D0BF2E287D032691D0D000003F49F47D0010801C854000007D000C313

06:50:13 20-02-16 AES:7C6C73 GES:82 2 .VH-VPH ! B6 1 BOEING 777-3ZG VIRGIN AUSTRALIA

    F83AVA0007/NANCDYA.ADS.VH-VPH14FF9D0BF2E287D032691D0D000003F49F47D0010801C854000007D000C313

06:50:14 20-02-16 AES:AABD7F GES:82 2 .N791UA ! B6 9 BOEING 777-222 UNITED AIRLINES

    F89AUA0840/NANCDYA.ADS.N791UA03010AFC575BD420080EB2691DBC34

06:50:51 20-02-16 AES:A9B275 GES:82 2 .N724AN ! B6 7 BOEING 777-323 AMERICAN AIRLINES

    F80AAA0072/AKLCDYA.ADS.N724AN07EDE5F4352A0791B31D9D0DEE38E438C68791812BF1C7245385C791800E12710AC0040F116998C004102B2F9F203F93

06:51:00 20-02-16 AES:7C4924 GES:82 2 .VH-OQE ! B6 2 AIRBUS A380-842 QANTAS

    J32AQF0011/NANCDYA.ADS.VH-OQE14FCEEABF1FBC88C33481D0D0074AC0332C88B899504B69C19ED488B80758F

06:51:17 20-02-16 AES:7C4924 GES:82 2 .VH-OQE ! B6 3 AIRBUS A380-842 QANTAS

    J33AQF0011/NANCDYA.ADS.VH-OQE0AFCF543F20FC88BB3881D9B8B

06:51:35 20-02-16 AES:7C4924 GES:82 2 .VH-OQE ! B6 5 AIRBUS A380-842 QANTAS

    J35AQF0011/NANCDYA.ADS.VH-OQE030189FD

06:51:50 20-02-16 AES:A9B275 GES:82 2 .N724AN ! 5Z 8 BOEING 777-323 AMERICAN AIRLINES

    M74AAA0072OS LAX /M56NTBU

06:52:54 20-02-16 AES:78037B GES:82 2 .B-6093 ! BA 7 AIRBUS A330-243 AIR CHINA

    J21ACA0194/BNECAYA.AT1.B-60932197888C3D9F3B982638F41C5E3294253834A4CB322254834E4417F44B0B0E6AD001A2682254835A2D62F194A04F5E

06:53:02 20-02-16 AES:AABD7F GES:82 2 .N791UA ! B6 1 BOEING 777-222 UNITED AIRLINES

    F91AUA0840/NANCDYA.ADS.N791UA14FC8DC3D589080EB5051D0DFE0453DF1BC80E84D902D6E405B4084D0063D9

06:53:32 20-02-16 AES:AACC5B GES:82 2 .N795UA ! B6 9 BOEING 777-222 UNITED AIRLINES

    F57AUA0870/BNECAYA.ADS.N795UA07F0BB2BA7E787C3B5A79D0DF3E7F3B62247C38896F8E273C733480E800E0A18F840001005889EF4F680

06:53:50 20-02-16 AES:7C4924 GES:82 2 .VH-OQE L _d 7 AIRBUS A380-842 QANTAS

    S09AQF0011

06:54:00 20-02-16 AES:A9B275 GES:82 2 .N724AN ! 5Z 9 BOEING 777-323 AMERICAN AIRLINES

    M75AAA0072OS LAX /M56RAR

06:54:07 20-02-16 AES:AABD7F GES:82 2 .N791UA ! B6 2 BOEING 777-222 UNITED AIRLINES

    F92AUA0840/BNECAYA.ADS.N791UA07FCA5EBD62AC80EB6311D0DFE0453DF1BC80E83FD02D6E405B4084D000E0E28F87FF82EAD

06:54:22 20-02-16 AES:C023AA GES:82 2 .C-FNND ! B6 2 BOEING 777-233 AIR CANADA

    F59AAC0034/BNECAYA.ADS.C-FNND07FC2F63B1D28791F66F9D0DFD5863B716880E830AFEEDBBC71C880E800E06F9023FFC6DE7

06:54:33 20-02-16 AES:78037B GES:82 2 .B-6093 ! 10 8 AIRBUS A330-243 AIR CHINA

    M43ACA0194POS180558,S 24.059,E143.318,1558,  462875,,,35997,139240

06:54:37 20-02-16 AES:7C6C73 GES:82 2 .VH-VPH ! H1 2 BOEING 777-3ZG VIRGIN AUSTRALIA

    F84AVA0007#M1BPOSS00000E178001,N00000E178000,055810,320,N02304W180000,062052,N05000W178000,M31,1479,1506/TS055810,200216D187

06:54:56 20-02-16 AES:7C6C73 GES:82 2 .VH-VPH ! B6 4 BOEING 777-3ZG VIRGIN AUSTRALIA

    F86AVA0007/NANCDYA.ADS.VH-VPH1400005BF4A407D0368E1D0D01C854000007D00550038E3C0B60C84D007DFD

06:55:15 20-02-16 AES:7C6C73 GES:82 2 .VH-VPH ! BA 5 BOEING 777-3ZG VIRGIN AUSTRALIA

    L74AVA0007/NANCDYA.AT1.VH-VPH2897AE4A405330

06:55:35 20-02-16 AES:7C6C73 GES:82 2 .VH-VPH ! B6 7 BOEING 777-3ZG VIRGIN AUSTRALIA

    F87AVA0007/NANCDYA.ADS.VH-VPH0301113E

06:55:51 20-02-16 AES:A9B275 GES:82 2 .N724AN ! B6 1 BOEING 777-323 AMERICAN AIRLINES

    F81AAA0072/AKLCDYA.ADS.N724AN14EE39DC38C88791B7D21D0DF1C7245385C7918AB6F5555C6C0D080E80F8BB

06:56:42 20-02-16 AES:7C6C73 GES:82 2 .VH-VPH ! B6 8 BOEING 777-3ZG VIRGIN AUSTRALIA

    F88AVA0007/NANCDYA.ADS.VH-VPH07002C8BF5BB07D0005E1D0D01C854000007D004CE038E3C0B60C84D000E0DD8FC80000F0DF1A1000010031EDF0400C9

06:57:38 20-02-16 AES:7C4924 GES:82 2 .VH-OQE ! H1 0 AIRBUS A380-842 QANTAS

    F23AQF0011#M1BPOSS03276E177541,S04000E177000,060113,350,N01000W180000,063642,N07000W176000,M39,1269,2516/TS060113,2002160DAC

06:57:46 20-02-16 AES:7C6C73 GES:82 2 .VH-VPH ! B6 1 BOEING 777-3ZG VIRGIN AUSTRALIA

    F90AVA0007/OAKODYA.ADS.VH-VPH0302215D

06:58:54 20-02-16 AES:7C4924 GES:82 2 .VH-OQE ! B0 2 AIRBUS A380-842 QANTAS

    J37AQF0011/NANCDYA.AFN/FMHQFA11,.VH-OQE,,060236/FRP0B2C1

06:59:03 20-02-16 AES:AABD7F GES:82 2 .N791UA ! B6 3 BOEING 777-222 UNITED AIRLINES

    F93AUA0840/BNECAYA.ADS.N791UA07FD0443D8AD880E42919D0DFE0453DF1BC80E82E602D6E405B4084D000E0E48F7400C1DA0

06:59:09 20-02-16 AES:A9B275 GES:82 2 .N724AN ! 5Z 4 BOEING 777-323 AMERICAN AIRLINES

    M76AAA0072OS LAX /FTM
    8080
    

06:59:18 20-02-16 AES:7C4924 GES:82 2 .VH-OQE ! B6 6 AIRBUS A380-842 QANTAS

    J40AQF0011/OAKODYA.ADS.VH-OQE030007FDB2F3F49FC88B82C81D0E0888FAC0000F08C9A58000100592BEC80D00B60C0000488B87E904FA4C16C1888B8094F5

06:59:33 20-02-16 AES:7C4924 GES:82 2 .VH-OQE ! BA 8 AIRBUS A380-842 QANTAS

    J42AQF0011/OAKODYA.CC1.VH-OQE600260C44910F595

06:59:42 20-02-16 AES:AABD7F GES:82 2 .N791UA ! B6 5 BOEING 777-222 UNITED AIRLINES

    F94AUA0840/NANCDYA.ADS.N791UA07FD1123D8FE880E832D9D0DFE0453DF1BC80E82B202D6E405B4084D000E0CF0FB00000F0CB1984000100E2B1EECC6A7

06:59:45 20-02-16 AES:7C4924 GES:82 2 .VH-OQE ! B6 9 AIRBUS A380-842 QANTAS

    J43AQF0011/OAKODYA.ADS.VH-OQE0AFDB2F3F49FC88B82C81D3139

07:00:01 20-02-16 AES:7C4924 GES:82 2 .VH-OQE ! B6 0 AIRBUS A380-842 QANTAS

    J44AQF0011/NANCDYA.ADS.VH-OQE07FDBBD3F4BF888B83241D0E0898FA3FFC0F08D1A3FFFC1005939ECA0D00B60C0000488B87D604FA4C16C1888B8063B9

07:00:02 20-02-16 AES:C023AA GES:82 2 .C-FNND ! B6 6 BOEING 777-233 AIR CANADA

    F61AAC0034/BNECAYA.ADS.C-FNND031207FCB313B3518791833F9D0DFD5863B716880E81DEFEEDBBC71C880E800E0C80FDFFF8100E145F160787

GES 82T


06:06:29 20-02-16 AES:7C4778 GES:85 2 .VH-OEI ! SA 7 BOEING 747-438 QANTAS

    M81AQF00270LV051000S

06:06:32 20-02-16 AES:7C146A GES:85 2 .VH-EBG ! H1 4 AIRBUS A330-202 QANTAS

    F74AQF0004#M1BRESREQ/AK,1158AF6

06:06:40 20-02-16 AES:7C146A GES:85 2 .VH-EBG ! H1 5 AIRBUS A330-202 QANTAS

    F75AQF0004#M1BPOSS14464E173177,,051015,380,S20000E168000,060500,S24220E163000,M46,0299,545/TS051015,022016DF1C

06:06:56 20-02-16 AES:7C4923 GES:85   .VH-OQD        AIRBUS A380-842 QANTAS

    30FF0001110A000000010000003A00000026000000EA1A08B802021FE9000000000000000000000000000000000001000656482D4F514400FFFFFFFF51464104

06:07:14 20-02-16 AES:A46368 GES:85 2 .N382HA ! 88 6 AIRBUS A330-243 HAWAIIAN AIRLINES

    M56AHA0451/HNLOCHA.MEPAB AT 0514
    

06:07:15 20-02-16 AES:7C4778 GES:85   .VH-OEI        BOEING 747-438 QANTAS

    30FE5501110A00000001000000410000002D00000046EF8B0B02040B4040D6632B7474517927006C06000000000000000011000000010EE8E80000090030322E31332E302E3004

06:07:33 20-02-16 AES:A46368 GES:85 2 .N382HA ! BA 8 AIRBUS A330-243 HAWAIIAN AIRLINES

    J41AHA0451/NANCDYA.DR1.N382HA8038

06:07:41 20-02-16 AES:7C146A GES:85 2 .VH-EBG ! 87 6 AIRBUS A330-202 QANTAS

    M72AQF0004HI GHIA. SPOT ON. VERY 
    LIGHT TURB BETWEEN
    THOSE 2 POINTS.
    THANKS.

06:07:45 20-02-16 AES:A4347B GES:85 2 .N370HA ! H1 5 AIRBUS A330-243 HAWAIIAN AIRLINES

    F10AHA0445#M1BRESREQ/AK,1158AF6

06:07:54 20-02-16 AES:A4347B GES:85 2 .N370HA ! H1 6 AIRBUS A330-243 HAWAIIAN AIRLINES

    F11AHA0445#M1BPOSS04054E177223,ARTOP,051128,400,AKUMO,053258,ATRAS,M54,14915,790/TS051128,02201633C9

06:07:59 20-02-16 AES:7C4923 GES:85   .VH-OQD        AIRBUS A380-842 QANTAS

    30FF0301110A000000010000001E0000000A000000BD2A6771020D640140D663AB8F7404

06:08:17 20-02-16 AES:7C4778 GES:85   .VH-OEI        BOEING 747-438 QANTAS

    30FE5601110A00000001000000410000002D0000007608922C02040B4040D6632B7474127927006C06000000000000000011000000010EE8E80000090030322E31332E302E3004

06:09:20 20-02-16 AES:7C4774 GES:85 2 .VH-OEE ! H1 5 BOEING 747-438 QANTAS

    F02AQF0015#M1BPOSS05156E173551,,051260,330,S05000E174000,051444,S02000E176000,M34,28221,2158,85,/TS051301,20021661CC

06:09:41 20-02-16 AES:A46368 GES:85 2 .N382HA ! 88 0 AIRBUS A330-243 HAWAIIAN AIRLINES

    M57AHA0451/HNLOCHA.69.0
    

06:10:18 20-02-16 AES:7C492A GES:85   .VH-OQK        AIRBUS A380-842 QANTAS

    30FF0501110A00000001000000410000002D000000A65D6F1F0204194040D6632B93742C0100006C06000000000000000011000000010E26E90000090030322E31322E302E3104

06:10:29 20-02-16 AES:A46368 GES:85 2 .N382HA ! 57 1 AIRBUS A330-243 HAWAIIAN AIRLINES

    M58AHA0451MEPAB0514400PADDY0607 594-53060015CLEAR   NONE    M.798/IC NONE     /LATS 21.389 /LONG E163.033
    /GS   473500/CAS 241/ETA 0739

06:10:33 20-02-16 AES:7C4778 GES:85   .VH-OEI        BOEING 747-438 QANTAS

    30FE5801110A00000001000000410000002D0000009A07962B02040B4040D6632B7474947827006C06000000000000000011000000010EE8E80000090030322E31332E302E3004

06:10:42 20-02-16 AES:A46368 GES:85 2 .N382HA ! B6 3 AIRBUS A330-243 HAWAIIAN AIRLINES

    J43AHA0451/BNECAYA.ADS.N382HA14F0CABB9F43C9C40D341D0DEE822B906749C4071AECE2DB853D09C4005F59

06:10:49 20-02-16 AES:A46368 GES:85 2 .N382HA ! B6 4 AIRBUS A330-243 HAWAIIAN AIRLINES

    J44AHA0451/NANCDYA.ADS.N382HA14F0CABB9F43C9C40D341D0DEE822B906749C4071AECE2DB853D09C4005F59

06:10:56 20-02-16 AES:A46368 GES:85 2 .N382HA ! H1 6 AIRBUS A330-243 HAWAIIAN AIRLINES

    F77AHA0451#M1BRESREQ/AK,1158AF6

06:11:02 20-02-16 AES:A46368 GES:85 2 .N382HA ! H1 7 AIRBUS A330-243 HAWAIIAN AIRLINES

    F78AHA0451#M1BPOSS21265E162571,MEPAB,051436,400,ISTEM,054436,PADDY,M53,06414,594/TS051436,02201688BF

06:11:08 20-02-16 AES:7C4774 GES:85 2 .VH-OEE ! H1 6 BOEING 747-438 QANTAS

    F03AQF0015#M1B/B6 NANCDYA.ADS.VH-OEE14FC6CBBDE1B880ECDE51D0DFE93EBE93E880E85CC0261DBFFFD880E800BDB

06:11:18 20-02-16 AES:A46368 GES:85 2 .N382HA ! BA 0 AIRBUS A330-243 HAWAIIAN AIRLINES

    J45AHA0451/BNECAYA.AT1.N382HA608253C1005057

06:11:27 20-02-16 AES:7C4778 GES:85   .VH-OEI        BOEING 747-438 QANTAS

    30FE5901110A00000001000000410000002D0000002A1F84C402040B4040D6632B7474557827006C06000000000000000011000000010EE8E80000090030322E31332E302E3004

06:11:28 20-02-16 AES:A46368 GES:85 2 .N382HA ! H1 2 AIRBUS A330-243 HAWAIIAN AIRLINES

    F79AHA0451#M1BRESREQ/AK,1158AF6

06:11:35 20-02-16 AES:A46368 GES:85 2 .N382HA ! H1 4 AIRBUS A330-243 HAWAIIAN AIRLINES

    F80AHA0451#M1BPER/TS051510,022016/PR3752,358,400,592,,0,0,,,180,,,P5,P40,36090,,3159,2556A4A

06:11:44 20-02-16 AES:A46368 GES:85 2 .N382HA ! BA 5 AIRBUS A330-243 HAWAIIAN AIRLINES

    J46AHA0451/BNECAYA.AT1.N382HA610453DA03EF4D

06:11:57 20-02-16 AES:A46368 GES:85 2 .N382HA ! BA 6 AIRBUS A330-243 HAWAIIAN AIRLINES

    J47AHA0451/BNECAYA.AT1.N382HA2194FA0A407637

06:12:08 20-02-16 AES:A46368 GES:85 2 .N382HA ! B6 8 AIRBUS A330-243 HAWAIIAN AIRLINES

    J48AHA0451/BNECAYA.ADS.N382HA030307F0A8BB9E6C09C40ED81D0DEE822B906749C406BFECE2DB853D09C4000B5E

06:12:30 20-02-16 AES:7C4778 GES:85   .VH-OEI        BOEING 747-438 QANTAS

    30FE5A01110A00000001000000410000002D0000001AF89DE302040B4040D6632B7474167827006C06000000000000000011000000010EE8E80000090030322E31332E302E3004

06:12:57 20-02-16 AES:A4347B GES:85 2 .N370HA ! H1 9 AIRBUS A330-243 HAWAIIAN AIRLINES

    F13AHA0445#M1BPOSS04354E176576,ARTOP,051632,400,AKUMO,053317,ATRAS,M54,20011,780/TS051632,022016B330

06:13:32 20-02-16 AES:7C4778 GES:85 2 .VH-OEI ! RB 1 BOEING 747-438 QANTAS

    M82AQF0027QFFLTDISP/~1                         

06:13:33 20-02-16 AES:7C4778 GES:85   .VH-OEI        BOEING 747-438 QANTAS

    30FE5B01110A00000001000000410000002D000000B78EF5B702040B4040D6632B7474D77727006C06000000000000000011000000010EE8E80000090030322E31332E302E3004

06:13:39 20-02-16 AES:7C4778 GES:85 2 .VH-OEI ! H1 2 BOEING 747-438 QANTAS

    F61AQF0027#M1B/B6 AKLCDYA.ADS.VH-OEI14DC715BE394C80ED02D1D0DDBBBBBEEEEC80E8258D82D843333080E800F85

06:13:57 20-02-16 AES:A46368 GES:85 2 .N382HA ! B6 9 AIRBUS A330-243 HAWAIIAN AIRLINES

    J49AHA0451/NANCDYA.ADS.N382HA07F0857B9D8C89C4108C1D0E4D00EE40040F4CB991C004100C8CFE680DEE822B906749C40652ECE2DB853D09C400FDEC

06:14:01 20-02-16 AES:A4347B GES:85 2 .N370HA ! B6 0 AIRBUS A330-243 HAWAIIAN AIRLINES

    J96AHA0445/NANCDYA.ADS.N370HA07FCA743EE2AC9C4109C1D0E4E18E4FFFC0F4DF193BFFC1008A31E540DFB8E8BE6EC09C403AAF90583D51C89C400D754

06:14:15 20-02-16 AES:A96779 GES:85 2 .N705DN ! B6 2 BOEING 777-232 DELTA AIR LINES

    F58ADL0040/AKLCDYA.ADS.N705DN07EEE19454DAC7D010D21D0DEEEC44556208024029F0588C71D7884D000E13B90F00000F12C1A280001029305F1019F4

06:14:16 20-02-16 AES:7C492A GES:85 2 .VH-OQK ! H1 6 AIRBUS A380-842 QANTAS

    F10AQF0007#M1BRESREQ/AK,1158AF6

06:14:25 20-02-16 AES:7C492A GES:85 2 .VH-OQK ! H1 7 AIRBUS A380-842 QANTAS

    F11AQF0007#M1BPOSS34193E158306,S34213E154596,051758,330,S34080E163000,054235,S34000E167000,M40,28765,4209/TS051758,200216A6B9

GES 85T


07:02:04 20-02-16 AES:7C4927 GES:85 2 .VH-OQH M _d 6 AIRBUS A380-842 QANTAS

    S33AQF0093

07:02:25 20-02-16 AES:A4347B GES:85   .N370HA        AIRBUS A330-243 HAWAIIAN AIRLINES

    01FF1F26111621313049980401000B00

07:02:27 20-02-16 AES:A4347B GES:85   .N370HA        AIRBUS A330-243 HAWAIIAN AIRLINES

    18FF

07:04:09 20-02-16 AES:AABD7F GES:82 2 .N791UA T _d 1 BOEING 777-222 UNITED AIRLINES

    S42AUA0840

07:05:57 20-02-16 AES:8991B9 GES:85   B-18311        AIRBUS A330-302 CHINA AIRLINES

    01FF1D261116900400980401000B00

07:07:39 20-02-16 AES:A2A38E GES:82 2 .N26952 W _d 8 BOEING 787-9 DREAMLINER UNITED AIRLINES

    S17AUA0099

07:07:39 20-02-16 AES:C023AA GES:82 2 .C-FNND U _d 7 BOEING 777-233 AIR CANADA

    S29AAC0034

07:09:00 20-02-16 AES:C023AA GES:82 2 .C-FNND Z _d 2 BOEING 777-233 AIR CANADA

    S30AAC0034

07:09:04 20-02-16 AES:AACC5B GES:82 2 .N795UA ! Q0 9 BOEING 777-222 UNITED AIRLINES

    M93AUA0870

07:09:10 20-02-16 AES:AACC5B GES:82 2 .N795UA R _d 0 BOEING 777-222 UNITED AIRLINES

    S53AUA0870

07:09:36 20-02-16 AES:C023AA GES:82 2 .C-FNND C _d 5 BOEING 777-233 AIR CANADA

    S31AAC0034

07:09:39 20-02-16 AES:A2A38E GES:82 2 .N26952 Y _d 0 BOEING 787-9 DREAMLINER UNITED AIRLINES

    S18AUA0099

07:09:43 20-02-16 AES:C023AA GES:82 2 .C-FNND D _d 6 BOEING 777-233 AIR CANADA

    S32AAC0034

07:10:04 20-02-16 AES:7C6C70 GES:82   .VH-VPE        BOEING 777-3ZG VIRGIN AUSTRALIA

    18FF

Mix of some GES82R and GES85R


That should give you a taste of what can be received on the R and T C-band channels. I hope some more people do try out C-band Aero. If you want to give it a go, version 1.0.4 of JAERO now supports these modes. If you do try it out please drop me a line as to how it goes.

I would recommend using the biggest dish you can get your hands on. One source says that they use 9 or 13 m dishes for ground stations. These signals have been successfully received off a 1.8 m dish from the UK so clearly the use of much smaller dishes is possible. Remember that not many amateurs have attempted to receive these signals so what makes a good set up is not really well known. While I have used a regular television C-band LNB for my own set up, if you're serious about receiving these signals then I would recommend against this. I would recommend using the lowest noise figure PLL LNB you can find as the frequency drift when using a regular television C-band LNB means continuously retuning the radio which makes long-term listening to these signals impractical.

Jonti
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Jonti. Last modified Sat, 20 Feb 2016 20:27:26 GMT.