ADS B brain fade

[daviddurrans]

Good Morning Gentlemen,

I'm hoping that the description of this problem proves more difficult that the solution. Any help will be very much appreciated.

2 systems set up in different aircraft and configured exactly the same way except for the Hex ID and Reg-ID.

Hardware: Pilot Aware, Farnell Cable, Funke TRT800

Software: August 2016

The transponders in both systems are getting GPS data as evidenced by accurate position report in transponder setup screen.

System 1:

Can see itself on its "traffic" screen as C,S,A and P in mode column with SIL 0 and SILs 0. There is nothing in the final column (aircraft and owner)

Can be seen on system 2 as C,S,A etc etc

In summary system 1 appears to function properly

One strange thing has been the occasional appearance of system 2 Reg on system 1 traffic screen EVEN WHEN SYSTEM TWO IS ENTIRELY SHUT DOWN. We presume that at some stage during testing we have put system 2 reg into system one (why would we do that?) and this is now cached. Can't remember doing this however.

System 2:

Cannot see itself on its "traffic" screen at all

Can be seen on system 1 traffic report as a PA, but no C,S or A. In the last column of the traffic report a full description of the aircraft and the fact it is privately owned is given.

Our first thought was that system 2 transponder may not be emitting but:

The Mode S can be seen by B'ham ATC (haven't asked them about ADS B since fitment not yet approved)
Both Mode S and ADS B can be seen on a POWER FLARM both close to and 1/2 mile from the Aircraft. On the face of it therefore the System 2 transponder is working.

We are considering a software reload onto the SD cards of both systems but wonder if there's anything else to consider.

Thanks

David

[Admin]

Hi David,

no need for a software reload just yet.

firstly I presume your testing was on the ground ?
If so, then I would assume the transponder is not going to be interrogated, so you are not going to see a Mode-S

ADS-B does not need interrogation, which is why you can see this on the ground / hangar.

Are both transponders at the same Firmware release ?

[Ian Melville]

Not relevant to the main issue, but if you use the same device to check the configure of the two PAW then it is very easy to inject the configure from one into the other. Make sure you go back to the home page for each device and confirm it is the correct one before changing an saving the config. Guess how I found that our

[daviddurrans]

Thank you both for your responses:

Re Firmware: I'll check we are both on the same firmware, although I'm fairly certain we are. It will be a while until I get back to the airfield but will post ASAP.

I remain puzzled as to why when checking with Power Flarm I see ADS B and transponder output from both aircraft, but only one (Aircraft 1) has output when checking with Pilot Aware. Aircraft 2 is not seen by Aircraft 1. Could be either transmission or reception.

Apologies if this is getting confusing.

David

[Moffrestorer]

David,

As a side issue, you mention that the traffic page for System 1 was showing SIL 0 and SILs 0 for its own transponder ADS-B transmission. For approval purposes, its the SIL 0 and SDA=0 that is the requirement.