AirNav Systems Forum
AirNav RadarBox and RadarBox24.com => AirNav RadarBox and RadarBox24.com Discussion => Topic started by: DaveReid on April 26, 2010, 04:10:08 PM
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I've been doing some more investigation of the apparent anomaly reported on a number of occasions whereby SIN local traffic doesn't appear to plot reliably. It occurred to me that, while it's possible on the network to watch arriving and departing traffic at many of the world's airports, I've never seen anything within 100 miles of SIN.
Following up my theory that proximity to the equator might have something to do with it, I've been analysing network traffic, with interesting results. It would appear that SIN arrivals from Europe, India, China, etc, are trackable until they get to 2°N, at which point they stop tracking. Similarly, departing traffic on these routes is invisible until it passes the same latitude northbound.
Next step was to look at South American equatorial coverage. We know Brazil has a good RadarBox network, so analysing traffic between Brazil and North America/Europe seemed a good idea. This time, there seems to be an invisible demarcation line at 2°S, after which southbound traffic suddenly appears and northbounds disappear.
Of course both of these phenomena could also be explained by lack of user coverage, so I'm not suggesting that the results are conclusive at this stage.
If anyone else would like to help out, I'm looking for evidence of aircraft tracking in the zone between 2°N and 2°S, anywhere in the world. My own RB is currently set up to generate alerts for flights withing 120nm (2°) of 0N 104.5E (i.e. the point on the Equator closest to SIN). No alerts so far - but then it's the middle of the night there at the moment so we'll see what tomorrow brings.
When reporting presence or absence of traffic in the twilight zone, details of which RadarBox version you're running would also be useful.
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There was cases a of certain aircraft not appearing in the map in the southern hemisphere due to a ANRB bug however this was rectified in the latest version.
We would be intrested in the results as well, as far as we knew from customers in the southern hemisphere it was fixed.
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There was cases a of certain aircraft not appearing in the map in the southern hemisphere due to a ANRB bug however this was rectified in the latest version.
We would be intrested in the results as well, as far as we knew from customers in the southern hemisphere it was fixed.
That may be related, but it doesn't sound like the same bug as the one that's affecting SIN, Brazil, etc - if indeed it's a bug we're talking about.
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Hi Dave
As I mentioned in an earlier post I am staying on the island of Bintan(about 45 mins ferry from Singapore). I can see a/c arr and dep from SIN on PlanePlotter but when I look at ANRB it advises "Flight Does not have position data".
I followed an a/c on ANRB and lost it at approx 2N, so your theory sounds correct.
There is obviously data as same a/c are appearing on PP.
FYI I am using v 3.13
Cheers
Mark
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First question: are you watching those aircraft on RadarBox network only or on the MyFlights grid?
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Watching on My Flights Grid. When I click on the aircraft (that I can see in PP), in the Grid it does not show that they are tracking. I followed several a/c on the map to 2N and then they disappeared.
Cheers
Mark
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Can you confirm you have Network flights turned off? Can you send us a screen shot of this situation happening? Adding to this can you confirm for how long you will stay in Singapore?
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Hi there
I have tried with Network flights turned on and turned off and same result. I am attaching current screen shot - both flights were displayed on PP. The PR502 flight only became visible on the map shortly after reaching 2N.
I am on holiday on Bintan Island until end of the week. Happy to assist.
Cheers
Mark
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I will also try to leave my feed on for a few hours,so if anyone would like to monitor ANRB and PP you will see the difference in what the two are displaying.
HTH
Mark
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as far as we knew from customers in the southern hemisphere it was fixed.
Yes it has been completely fixed for my location
Mike
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I have tried with Network flights turned on and turned off and same result. I am attaching current screen shot - both flights were displayed on PP. The PR502 flight only became visible on the map shortly after reaching 2N.
I am on holiday on Bintan Island until end of the week. Happy to assist.
Hi Mark
I've dug out my notes from diagnosing the previous "rectangular black hole" bug last November, and I'm pretty sure that it's not connected with the "Equatorial black hole" - see www.airnavsystems.com/forum/index.php?topic=3774.msg38312#msg38312
Could I suggest that next time you see an aircraft dropping off the radar at the 2° boundary, you check your aircraft list to see whether
a) the aircraft has also disappeared from there, or
b) it's still showing in the list, but the coordinates are stuck, or
c) it's still in the list, and the coordinates are continuing to update (in which case what do they say?)
HTH
Dave
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Hi Dave
As far as I can determine what happens is that the aircraft stays in the aircraft list but the information disappears from the lat/long columns - they just go blank when aircraft moves within 2N boundary.
HTH
Mark
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As far as I can determine what happens is that the aircraft stays in the aircraft list but the information disappears from the lat/long columns - they just go blank when aircraft moves within 2N boundary.
Hadn't thought of that option :-)
AirNav - does that help the diagnosis ?
If it's a position decoding bug (which my money is still on, as we've not heard any reports of aircraft dropping out of the sky) then it's an obscure one.
I know the CPR (Compact Position Reporting) algorithm pretty well and I'm not aware of anything that's supposed to change at 2°N or S - that's nowhere near a transition latitude (the boundary where the number of longitude zones changes).
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I have mentioned this before ,Having stayed in the crowne plaza hotel at Singapore airport for 2 nights last year, aircraft arriving and departing right in front of me and not one showing
on the radar map.
It was all very strange.
Ian
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AirNav - does that help the diagnosis ?
And answer came there none ...
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We are looking into it.
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We are looking into it.
Good - I'm encouraged to hear that AirNav are looking into the black hole !
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I have stayed on the 30th floor of the Conrad and can't say that I noticed a problem. The problem with hotel windows is that some seem to shield the signal greatly. The first time I noticed this was in Dubai. I had a great room with an unobstructed view and was picking up virtually nothing. I then opened the window and put the antenna on a ledge. Within seconds my screen was full of stuff up to 250 miles away....
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Lead in the glass and/or metallic sun tint.
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I am now back in Australia and wasn't able to "solve" the problem of the "Black Hole of Singapore".
There was definitely no issue re windows etc as the aerial was outside at all times. I was getting reception of up to 240nm with Radarbox, as long as aircraft were north of 2N. Once they flew south of 2N they disappeared off the map and appeared in the aircraft list with lat/long info showing blank, (but still appearing on the map in Planeplotter).
Cheers
Mark
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Thanks, Mark.
I guess we'll have to wait for AirNav to diagnose and fix the issue. If it helps, I can confirm that my Network capture still isn't logging any traffic between 2°N and 2°S in the meantime.
Incidentally, even though the Network is up at the moment, the status page says it's on maintenance, looks like someone forgot to reset it !
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It may be a while before I return to Singapore, but hope AirNav can fix the problem before then.
Cheers
Mark