Hi,
I am new to this subject and would like to build my own receiving equipment for monitoring automatic transmissions of the ADS-B kind. I have no experience of building stuff that works at microwave frequencies, even the bottom end such as 1090MHZ, and short of using a suitable sat TV module and cobbling the tuning of it together, I doubt I could do it well. However, in the past, I have built a number of receivers operating at VHF frequencies.
I have been reading around the subject on the net, and seem to think that there is a parallel VHF system besides ADS-B has also been mandated for civil aircraft, and it looks like it might cover the same kind of data. If this is true, I think I would have a lot better chance of building a receiver to work on the VHF airband frequencies, since I built an FM WEFAX satellite receiver about twenty years back which worked very well.
So, my questions are:
Is VDL-4 being used alongside ADS-B?
Does it send the same data as ADS-B?
What frequencies are used for VDL-4? I'll probably make a crystal controlled L/O for the project.
I envisage that the main problem might be in having to programme the microprocessor myself to decode the data. I know that chips are already available pre-programmed to decode ADS-B, but the data rates of ADS-B and VDL-4 are very different, which probably means the chip would need different programming. This would be a deal breaker for me, I suspect, as that is not my game.
Many thanks for any help any of you experts might be able to share here.
Perhaps I am barking up the wrong tree with this idea, in which case feel free to disabuse me of the half baked plan.
I am new to this subject and would like to build my own receiving equipment for monitoring automatic transmissions of the ADS-B kind. I have no experience of building stuff that works at microwave frequencies, even the bottom end such as 1090MHZ, and short of using a suitable sat TV module and cobbling the tuning of it together, I doubt I could do it well. However, in the past, I have built a number of receivers operating at VHF frequencies.
I have been reading around the subject on the net, and seem to think that there is a parallel VHF system besides ADS-B has also been mandated for civil aircraft, and it looks like it might cover the same kind of data. If this is true, I think I would have a lot better chance of building a receiver to work on the VHF airband frequencies, since I built an FM WEFAX satellite receiver about twenty years back which worked very well.
So, my questions are:
Is VDL-4 being used alongside ADS-B?
Does it send the same data as ADS-B?
What frequencies are used for VDL-4? I'll probably make a crystal controlled L/O for the project.
I envisage that the main problem might be in having to programme the microprocessor myself to decode the data. I know that chips are already available pre-programmed to decode ADS-B, but the data rates of ADS-B and VDL-4 are very different, which probably means the chip would need different programming. This would be a deal breaker for me, I suspect, as that is not my game.
Many thanks for any help any of you experts might be able to share here.
Perhaps I am barking up the wrong tree with this idea, in which case feel free to disabuse me of the half baked plan.
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