Author Topic: PAW not receiving traffic  (Read 366 times)

mutley

PAW not receiving traffic
« on: February 28, 2021, 11:35:33 am »
New Rosetta install with "internal" antenna kit.  All of the icons on the home page showing "green", power OK, GPS fix etc etc.  Antennas mounted on the glareshield.

The traffic page is only showing two or three very local aircraft - it isn't picking up any of the high altitude CAT traffic that I would expect it to see (this was yesterday (Saturday) at Goodwood, I had a look on FR24 and there was enough out there that I would have expected at least a handful of of airliners shown).

I don't suspect a specific install issue at this stage as it was the same when we got it out of the box for a system check and had the antennas on the roof of the truck.

I did try swapping the antennas around (so that they were connected to the wrong outputs) and picked up a couple of extra aircraft but it wasn't a particularly definitive test of anything.

Any ideas of what to check next time I can get to the aircraft?

Thanks

Steve

steveu

Re: PAW not receiving traffic
« Reply #1 on: February 28, 2021, 11:45:14 am »
Check in the relevant set up page that there are no limits set on the aircraft that PilotAware will detect or flag up?

Can't remember what it's called, but it sets limits for reports.




mutley

Re: PAW not receiving traffic
« Reply #2 on: February 28, 2021, 11:58:40 am »
I don't think that the setup pages limit what appears on the Traffic page?  Doesn't everything it receives get shown on there, with the limits just affecting what is displayed on your connected device?

steveu

Re: PAW not receiving traffic
« Reply #3 on: February 28, 2021, 12:13:37 pm »
I don't think that the setup pages limit what appears on the Traffic page?  Doesn't everything it receives get shown on there, with the limits just affecting what is displayed on your connected device?

I think (and I believe I read somewhere) that the limits in the PAW affect everything, but the quickest answer will be for you to prove me wrong by testing my hypothesis.

exfirepro

Re: PAW not receiving traffic
« Reply #4 on: February 28, 2021, 01:13:50 pm »
Hi mutley,

You have confirmed that all the indicators on the PAW Home Screen were a Green, but was the aircraft outside or in the hangar?

You are correct, everything received should be displayed on the PAW ‘Traffic Page’, with Traffic which will be excluded from transmission to the connected display device ‘Greyed Out’.

Having said that, for testing purposes and to gain familiarity with the system on the ground, you should as Steve advises set all filters on the PAW Configure Screen to as wide open as possible.

Enable Mode C/S to receive Bearingless Targets (+Filter later if you are using this in a transponder-equipped Aircraft).
Set Mode C/S to Long Range Detection.
Leave Height Filters as wide as practicable.
Set Mode-S/3D to ‘On’ if you are in range of a PAW Ground Station and want to receive uplinks.

For ‘Known Position’ Targets set all filters as wide as possible in PAW Configure then restrict altitude later in your display software (the Altitude Filters in the display software only control Positional target warnings).

If you are using SkyDemon, remember to set Third Party Devices to PilotAware and set the Altitude Filter (wide initially).
Also remember to enable Bearingless Targets in SkyDemon if you want these alerts.

Hope this helps.

Regards

Peter

mutley

Re: PAW not receiving traffic
« Reply #5 on: February 28, 2021, 03:34:24 pm »
Thanks - the issue I have us that all of the “opening up” of settings will make no difference if the PAW unit isn’t showing more than a few aircraft on the Traffic page.

We ran the unit first with the antennas on the roof of the truck outside yet hangar.  Didn’t pick up much traffic but thought maybe we were shielded by the hangar.  Installed the unit in the aircraft, positioned it outside away from the hangar, tried a number of different orientations to make sure the antennas had a line-of-sight to London, and still only a few very local aircraft being shown on the Traffic page.

I have got some other antennas kicking about back at base so will maybe try them to see if it is an antenna problem.

steveu

Re: PAW not receiving traffic
« Reply #6 on: February 28, 2021, 04:30:19 pm »
We ran the unit first with the antennas on the roof of the truck outside yet hangar.  Didn’t pick up much traffic but thought maybe we were shielded by the hangar.  Installed the unit in the aircraft, positioned it outside away from the hangar, tried a number of different orientations to make sure the antennas had a line-of-sight to London, and still only a few very local aircraft being shown on the Traffic page.

If you are comparing with FR24 then I assume it's an ADS-B/mode-S lack of reception?

ADS-B will come in on the 1090 antenna, as will bearingless mode-S, mode-S with bearing will need a ground station, and will arrive via P3i.

Is this a sensible explanation or am I wrong twice?

ADS-B should be seen, and at distance. So, maybe looking to compare just ADS-B traffic? This is not ground station dependent.

Otherwise, some of your missing traffic could be explained with lack of a ground station, unless there is one at the airfield in question, so there should be no issue?

And the sum total of this post can therefore be ignored.


mutley

Re: PAW not receiving traffic
« Reply #7 on: February 28, 2021, 06:23:54 pm »
We probably won't get a chance to find out until we are able to fly it.  If we still don't see traffic then I will have a play with the antennas.

Thanks to both for your input.

exfirepro

Re: PAW not receiving traffic
« Reply #8 on: March 01, 2021, 10:11:19 am »
Thanks - the issue I have us that all of the “opening up” of settings will make no difference if the PAW unit isn’t showing more than a few aircraft on the Traffic page.

We ran the unit first with the antennas on the roof of the truck outside yet hangar.  Didn’t pick up much traffic but thought maybe we were shielded by the hangar.  Installed the unit in the aircraft, positioned it outside away from the hangar, tried a number of different orientations to make sure the antennas had a line-of-sight to London, and still only a few very local aircraft being shown on the Traffic page.

I have got some other antennas kicking about back at base so will maybe try them to see if it is an antenna problem.

Hi again mutley,

After building, every PAW unit is run on a test rig prior to dispatch to check that everything is as it should be, so faulty units are virtually unknown, which is why having determined that you are getting ‘All Greens’ on the Home Screen, we’ve been concentrating on settings.

My earlier point was that with extremely limited GA traffic about, you are highly unlikely to see any PilotAware or SkyEcho traffic at the moment unless someone you know to be so equipped is flying locally with their equipment operational at the time you are testing. This only leaves commercial ADS-B (potentially visible at up to 100 miles or so), or High Power CAT Mode-S - which is much less prevalent since the loss of FlyBe and will only show on the Traffic Screen if you have Mode C/S detection enabled - it is ‘Off by Default’ - and Mode C/S Horizontal Sensitivity set to ‘Long Range’ and something like +/- 40,000ft (for testing).

With the settings I advised above, you should expect to see at least some ADSB traffic, though you will need to be patient. Goodwood is still a fairly long way away from the likes of Heathrow and Gatwick, and I’m not sure how busy Southampton is just now, so you might have to wait a while. I am only a few miles from Edinburgh Airport and my Ground Station, which on 1090 covers most of Scotland and Northern England with optimised high gain antennas, often has long gaps with no traffic whatsoever at the moment.

It is of course ‘possible’ that the 1090 internal antenna might not be performing as well as expected, though I am not aware of a high failure rate. 1090 signals can usually be picked up on the proverbial ‘piece of wet string’, but make sure that the antenna is vertical (or as near as possible) and that it is properly connected to the correct antenna connection (though if you’ve got them the wrong way round you should still receive 1090 signals on the 869.5 antenna). Next carefully open the end case of the Rosetta and make sure that the pigtail cable is properly connected into the receiver dongle and that the dongle is properly seated in the USB socket. If after rebooting and waiting a while you are still seeing no traffic and have another suitable antenna give it a try, or even try a length of fine wire which fits neatly into the centre of the 1090 antenna socket, or directly into the inner point of the socket on the receiver dongle itself (missing out the ‘pigtail’). Any length over a few centimetres will do - longer isn’t an issue for this test. Don’t however try this trick on the 869.5MHz P3i side though as it could damage the transmitter.

Let us know how you get on.

In either case, it would be useful if you could post screenshots of the Home, Configure and Traffic Screens, so we can see for ourselves what is (or isn’t) showing.

Best Regards

Peter

steveu

Re: PAW not receiving traffic
« Reply #9 on: March 01, 2021, 11:29:40 am »
There is only very little traffic even during the day.

Screen dump from PWEgerton, 2021-03-01 @1124, in case it helps.