Radar Box Overseas

[ianmalc]

I Have just returned from a trip abroad with my faithful RB friend , and these are
my findings.
Hong Kong , stayed in the regal hotel on the 9th floor and RB managed to pick
up virtually everything.
Sydney , stayed in stamford plaza on 11th floor with excellent view of airport , RB picked
up most of the visiting airlines but most of the Qantas stuff does not transmit ADSB with the exception of the 747s and A330s and a few of the 737S.
Not many Virgin blue transmit either , but of course all aircraft appear in my flights with all the necessary information required.
Singapore totally different story here ,stayed in the crowne plaza on 11th floor and not one aircraft was picked up on the map over 2 days ,even though they were taking off and landing right by my window.
I Tried moving the ariel to every location in the room and the window couldnt have been any bigger, so i think Singapore really is a Radarbox black spot.
Still it was a great trip ,loads of nice aircraft seen.
I am off to Dubai soon ,hoping i will have more luck there with my RB than in Singapore.

Ian

[AirNav Support]

Hi Ian,

This is intresting, as support has been contacted by a customer in SGP with similar issues, we were thinking after certain tests that it must be his box with the issue but now not so sure.

[DaveReid]

This is intresting, as support has been contacted by a customer in SGP with similar issues, we were thinking after certain tests that it must be his box with the issue but now not so sure.

It's hardly rocket science - some aircraft have ADS-B, some have only Mode S, and some have neither.

A database that tracks the ADS-B/Mode S fit of individual aircraft might not be a bad idea ...

[AirNav Support]

Sorry Dave we should have been more clear.

In SGP, very little ADS-B traffic is being picked up (i.e less than 2 per day). Considering SGP is serviced by major airlines that we know have ADS-B its very strange why there is some sort of ADS-B blanket there.

[tarbat]

From http://www.canso.org/xu/document/cms/streambin.asp?requestid=AF096FE3-A79B-47F6-B442-AEB1874EDA0A

"A review of aircraft types in the area during Jul-Oct 2008 reinforced this, where 61.9% were assessed as ADS-B capable."

Could the Comsoft project be having an impact - I can't see how though.
http://www.comsoft.de/html/atc/press/releases/2009/ads_b_caas.html

[mjread]

Thanks for your feedback Ian.  At least I know now that my RB most likely isn't faulty - but that does mean that I really won’t have much luck using it in Singapore.  Seems I’ve bought myself a white elephant here :(
It is really bizarre though - I am experiencing the same as what you saw, absolutely nothing around Singapore, yet I would occasionally pick up aircraft over Malaysia which rules out something jamming that particular frequency.  I’ve tried it in quite a few different locations around Singapore and still nothing.  Mode S is fine though – I can see the details of the aircraft, just not where they are.
Support have suggested that it may be because of the ocean distorting the ADS-B signals, but if that was the case and the ocean really would cause a complete block of ADS-B messages I would have thought they would have had a lot more problems worldwide.
What turns everything on its head though is that I mentioned my problem in another thread - http://www.airnavsystems.com/forum/index.php?topic=3072.0 – where Protzenalp said that he has had success with receiving ADS-B traffic whilst in Singapore, so I’m really baffled by this one.

Asking a silly question here, but is there any reason why an aircraft would stop broadcasting ADS-B messages?  It doesn’t rely on receiving a request to do so from a ground station does it?

I also spotted details of the Comsoft project and also wondered if that had anything to do with it, but also for the life of me can’t think what.  It’s only a radio signal after all.

[daelight]

I am in Tokyo and pick up Singapore Airlines aircraft - the A380 just departing NRT as I type... I notice alot of ANA and JAL not showing locations, maybe thats a good thing as map would be packed!

[SpeedWagon]

Hi Ian,

This is intresting, as support has been contacted by a customer in SGP with similar issues, we were thinking after certain tests that it must be his box with the issue but now not so sure.

I looked at some of my old logs and almost 100% of the Asian flights into Vancouver, Canada that I can pick up in Victoria are broadcasting ADS-B.  I would doubt they turn it on coming to the west coast.

[pjm]

likewise - while I was typing this reply 2 planes were leaving for or via Singapore from Sydney, And looking at my logs all Singapore based planes bar 1 are broadcasting ADS-B.

[mjread]

The aircraft are definitely broadcasting ADS-B before they get to Singapore.  During one test I tracked a Singapore Airline flight that popped up over Malaysia destined for Singapore.  I followed this flight on the map for a little while until it got close to Singapore and then I stopped receiving any ADS-B messages from it and it dropped off the map.  Mode S was still coming in strong and was updating right up until landing at Singapore Changi Airport.

[ianmalc]

It really is strange why i couldnt pick up anything in Singapore especially when we know that most of the Singapore airlines fleet transmit ADSB.
Qatar , Emirates , Fedex , United , Ups , Turkish all of which we know transmit and yet
nothing recieved.

Ian

[jgrloit]

Can someone remind me - Does ADS-B normally get transmitted on a timed prompt from the Aircraft, or is it ONLY in response to a ground based interrogation?
If the latter could Singapore have decided to NOT prompt, but use just the Mode-S and normal radar for it's control and positioning??

[AirNav Support]

ADS-B is transmitted regardless of interrogation.

[DaveReid]

ADS-B is transmitted regardless of interrogation.

Specifically, position reports are sent by airborne aircraft on average twice per second.

[Johnn]

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