Class "C" airspace, planes/etc, transponders.

[flying dog]

Hey folks.

 

I live in Sydney and am close to the airport.

 

I also have (now) broadband.

 

Now and then I go to "flight tracker 24" to watch the planes around the sky.

 

A while ago in the evening I saw a helo' going west bound over my place with flashing blue lights.

 

Quickly loaded flight tracker 24 and looked for it. NOTHING!

 

I have also noticed other "small" planes flying around WELL WITHIN "CHARLIE" AIRSPACE but they do not show up on flight tracker 24.

 

I probably should pull my finger out and re-install my RADARBOX software and plug it in and see what I see, but where/how I live it is not easy to get the antenna outside with a clear view of the sky.

 

So my question is: I have been told that to fly in "Charlie" airspace you MUST HAVE a transponder, and yes there are transponders and there are transponders....

 

But shouldn't I see them on those programs?

 

 

[Guest Nobody]

not unless they have ads-b

 

 

[flying dog]

Um...... ads-b?

 

English may help with that.

 

 

[mAgNeToDrOp]

I do better with pretty pictures:

 

Link

 

As far as I know the aricraft needs to be ADS-B equipped in order to be visible on programs such as FlightRadar24

 

 

[flying dog]

Ok, shall look at the link.

 

So, I'm still kinda confused.

 

(link not looked at at time of posting)

 

So altough they have a Xponder, they don't have ADS-B - which is needed for their position to be plotted.

 

Ok. Makes sense I guess.

 

 

[Guest Nobody]

Um...... ads-b?English may help with that.

Google may help too.

 

The Flight radar website works by having a volunteer with a ground station. The ground station is a radio and a computer with an internet connection. The aircraft has a gps and a mode s transponder. The plane broadcasts it's position and anyone(ATC or the volunteer) who has the equipment can decode the position. The computer uploads this to the internet and flight radar shows it in the page.

 

Mode c transponders work differently.

 

 

[flying dog]

Ok. So if I was "right" in guessing Mode C, what is/are mode D transponders?

 

I have one of those things, but just have not got around to re-instatlling the software - as said earlier.

 

 

[mothra]

Um...... ads-b?English may help with that.

Automatic Dependent Surveillance - Broadcast

 

Not really English yet is it, try, http://www.airservicesaustralia.com/projects/ads-b/

 

 

[rankamateur]

Are you sure it is real-time, look at the time stamp on the screen, you may be seeing what went by an hour ago. That might stop you using flight radar to aquire ground-to-air targets. My daughter flew to Auckland two nights ago and it showed on Google as in flight but no sign of ANZ726 on fight radar, was a bit un-nerving here at home.

 

 

[Mriya]

Fltradar24 is real time in Oz, but has a 5min delay in the USA (signified by the different color aircraft on the display). As rightly pointed out it receives its aircraft position data via a private network of ADS-B receivers which pick up the broadcast GPS location that is sent out by all ADS-B equipped aircraft. Most, if not all large airliners are now ADS-B equipped, however at this time only a small number of GA / Charter aircraft are set up with ADS-B at this time. I was recently involved in the import of a C182 which had ADS-B equipment. ADS- B overcomes some of the limitations of conventional surveillance radar in that if two aircraft operating in Mode A or C are in close proximity to each other the return signal from the transponders in each aircraft occur simultaneously, effectively scrambling the return data. Airservices Australia would love to have every aircraft ADS-B complient, allowing them to shut down the radar network. You may remember they had a push for this outcome when faced with having to upgrade their radars a few years back. Probably good that they didn't succeed in that bid as the ongoing cost of having every aircraft ADS-B compliant would be borne by us all, even though at the time they were proposing subsidies for equipment fitment in all aircraft.

 

 

[rankamateur]

ZK-OJC must be eqipped with the right transponder because it's turn back to Melbourne was seen on FR24, but ZK-OJD flying the same route didn't show up, it must have had it's transponder turned off.