Verification of ADS-B out on Traffic page

[sturs]

Hi all,

I am currently working to get my Skymap 3c connected to a Trig TT31 to enable ADS-B out. 

I have a query regarding the configuration of PAW and the result on the Traffic display on the interface page.  I understand that, if PAW is set up with the a/c hex code, then the traffic information supplied to any connected nav device will have 'own ship' info suppressed.  My question is, will own ship info still be displayed on the Traffic display on the interface page?

I ask as yesterday I could not see my a/c on the Traffic list.  Other ADS-B and Mode S traffic showed up well.  I just want to know whether I should be chasing a PAW configuration issue or a transponder fault!

I am running latest hardware config (homebulit) and software update. (And, incidentally, auto-update of software to 20160708 worked well.)

Many thanks,

Stuart

Sent from my iPad

[Admin]

I have a query regarding the configuration of PAW and the result on the Traffic display on the interface page.  I understand that, if PAW is set up with the a/c hex code, then the traffic information supplied to any connected nav device will have 'own ship' info suppressed

This is correct

My question is, will own ship info still be displayed on the Traffic display on the interface page?

Yes it should, there is a simple filter before transmitting to NAV that suppresses sending the data if the ICAO
value in the database entry, matches the one entered via the User Interface. But this is not done for the traffic
table.

I ask as yesterday I could not see my a/c on the Traffic list.  Other ADS-B and Mode S traffic showed up well.  I just want to know whether I should be chasing a PAW configuration issue or a transponder fault!

This may not be a fault pers se, let us assume that your transponder is currently running in Mode-S, then in order
to be detected it MUST be interrogated by ground radar, otherwise it will not transmit.
ADS-B on the other hand is intended to be (A)automatic, in other words it will broadcast its data automatically, without being interrogated.
Interpretation of automatic is now down to the transponder vendors understanding.
So should this only be when moving for instance ?

I would recommend asking Trig, under what circumstances do they suppress/enable the ADS-B transmission.

it could be a configuration issue, it could be an intended use - ie position is not changing

Thx
Lee

[sturs]

Hi Lee,

Thanks very much for the quick reply.  That clears up my understanding of what may be happening.  I think a quick flight test might be the easiest way to check.

Rgds, Stuart

[Ray McKeown]

Of no direct assistance to the OP with the Trig Xpdr,  but for general information, a FUNKE TRT800 Xpdr will automatically broadcast ADS-B out whilst on the ground  (i.e not moving, switched on in mode S,  in receipt of a valid GPS signal and no suppression from a "ground" switch).

Regards, Ray 

[sturs]

Thanks Ray.  I've sent an email to Trig support.  I'll post back here when I hear from them.

Stuart

[sturs]

Trig support very helpful and quick.  They advise that the TT31 will squitter whilst stationary on the ground.  Only STBY and OFF will stop squitter and interrogation replies.

Just in case the info helps anyone else..

Stuart

[Admin]

Hi Stuart,

So making the assumption that you are squittering, could it be that the signal from the transponder is overloading the RF front end of PilotAware, and hence it is not decoding ?

The test for this would be to get some distance between your PilotAware and the Aircraft.

One other thought, was this test outside, or in a hangar, if in a hangar did your GPS supplying NMEA to your TT31 have a lock and hence passing data ?
Without a lock, I would guess the transponder would not send data.

Thx
Lee

[sturs]

Thanks, Lee.  The test was outside and the transponder ADS-B position monitor showed the position being used for ADS-B.  But overload of the RF front end is a distinct possibility.  I'll go and check it out.....  Oh, and you're quite right about the transponder not transmitting ADS-B if it doesn't receive a position from the GPS.  It comes up with an error message along the lines of 'No ADS-B Data'.

[sturs]

Interesting afternoon yesterday.  I got immediate indications of ADS-B reception when PAW about 40m from a/c.  Then I brought PAW right next to a/c without losing it on the Traffic display.  So it doesn't look as though RF overload is an issue.

After that I lost my own a/c's ADS-B and Mode S info.  At the same time I had good, solid traffic info from other a/c using Mode S, ADS-B and, from one a/c returning to my base airfield (Coventry), a good PAW position.  It rather looks as though I have a transponder system problem, which I shall investigate further next week.

Thanks for all the support, Lee.

Stuart

[Admin]

Hi Stuart

I wouldn't be so quick to jump to the conclusion that the transponder has an issue, the reason I say this is the following

When an entry is made into the PilotAware traffic table, it is maintained for 10 seconds after reception.
Not sure how fast you can walk 40m 

So in other words at the point where the traffic display drops your A/C, the signal was last successfully received 10 seconds prior
does that make sense ?

Thx
Lee

[jrpike]

My first post to this forum so I hope this gets picked up as it's rather an old thread, however one directly relevant to my question.

What exactly does the mode column in the traffic screen tell me? I ask because I have recently connected my PAW unit to my Funke TRT800A transponder to enable ADSB-out and have successfully used another PAW unit to check the transponder output. It does indeed show CSAP against my registration on the top line. However, if I switch my own PAW (the GPS position source) off, and even pull out the USB plug sending the data to the transponder, the A still remains in the mode column.

Does the A simply mean the transponder is squittering with or without a valid position? If so, then how can I truly check the ADSB-out functionality?

Bearing in mind Lee's July 15th 2016 post, to which this is a reply, it could be that I simply didn't wait long enough to see the A disappear. I will check again but I'm sure I waited a lot more than 10 secs!

Thanks,

Richard.

[Admin]

Hi Richard

I think these fields are latches, they simply report if data was ever rec iver for the specific type

Try disconnecting paw as the gos source, then turning on the paw acting as receiver, this should not report an A

Thx
Lee

[jrpike]

Thanks, Lee. I have repeated the experiment and all is behaving correctly. False alarm!

However, I do notice that, although the P in the mode column is rock solid, the CSA is a bit intermittent, mostly visible but disappearing for a few seconds every 20 secs or so. Is that normal or does it suggest a problem?

If anyone is familiar with the Funke TRT800A transponder, is it possible to display, perhaps in test mode, the actual position being sent by the GPS source?

Thanks,

Richard.