ADS-B has several advantages, for example it broadcast even when not under radar coverage. This is also a major difference between active and passive TAS systems. Passive systems (Zoan for example) will rely on the interrogation by the ground based radar. Active TAS systems (Avidyne for example) will interrogate themselfs. Therefore they will also work when you fly in an area with no radar coverage.
Traffic information outside radar coverage is a huge advantage, especially between mountains, or low level above sea as two examples.
The huge advantage of ADS-B is the low cost compared to active systems. In the EU it is mandatory for large (> 5700 kg MTOW and fast (> 250 Kts) aircraft between 2015 and 2017.
Who uses ADS-B? Pilots for traffic awerness, ATC operators for a much high resolution and seeing your intentions, ground operators. Ground operators have a better view than with ground radar, again much more details, including aircraft span etc. Follow me / mobile marshallers / controllers that can see in their car the with of your aircraft, determine which taxi ways are suiteable, recognize aircraft position on ground even in poor visibility.
The ground equipment as well will be much more affordable.
ADS-B will be the future, and it will get introduced to general aviation on the long run.
Their are also ADS-B transponders available for UAV / UAS and for ground vehicle’s. On large airports this will be a major advantage as well as the ground controller can see all relative traffic on airside, and give crossing clearance during poor visibilty while having better situational awereness.
My TCAS is set up to show traffic
Do note that TCAS and TAS or not the same, TAS systems give traffic advisory only, meaning that it informs you on the traffic (traffic traffic). TCAS systems will do the same AND give resolution advisories to prevent collision, a TAS system will not. TCAS computers communicate with eachother, leading to a climb (climb climb) in one aircraft and decend in the other (decend decend). The Avidyne system is TAS system, not a TCAS system.
Avidyne promisses a ADS-B IN upgrade for years, however it still is not available AFAIK.
ADS-B will be of enormous benefit to GA. Not only pilots but GA airfields can run ADS-B receivers showing all traffic in the vicinity. I’ll have to look at my setup and see what I can do to make us as conspicuous as possible and also to received ADS-B and display somewhere.
The “man” at an airfield can already run one of the plane spotter boxes and see Mode S traffic.
And many do 
It’s a cheap and easy way to see where people are – well those who have a Mode S transponder at least.
He just isn’t allowed to make use of the information, in any way openly suggesting that he can see traffic on it. For that he would need a certified radar feed and be a radar qualified ATCO. The airfield would then have to close, due to the cost.
Is there any prospect of getting a lower cost ADS-B radiator than a Mode S transponder already costs (say 2k)?
He just isn’t allowed to make use of the information, in any way openly suggesting that he can see traffic on it.
Why would he not be allowed? What is the legal basis?
I think the CAAs should refund us for Mode S, 406MHz ELT and 8.33kHz, all of which are useless and instead mandate ADS-B Out for all aircraft and require it to be permanently on (even make it impossible to turn off). That would be a big safety improvement and EASA could rightfully keep that S in their name.
The “man” at an airfield can already run one of the plane spotter boxes and see Mode S traffic.
This is only partially true. With the standard (non ADS-B) mode S transponder these boxes can only see:
24 bit technicall adress
Flight ID or call sign
Altitude
Squawk code
It can not determine position other than using a direction finding technique, to find a bearing and signal strength as indication for distance. This is how these passive traffic devices work. This methode is rough to say the least.
Most plane spotter boxes use ADS-B as well. ADS-B is used to send that extra bit of information such as GPS position. That is also the reason why you see mainly airliners on these, as general aviation isn’t into ADS-B yet.
ADS-B is allready in use at large airports, both in air AND on the ground for both aircraft and vehicles.
Mode S transponder will always be the cheapest way to have ADS-B out, as it already transmit on the right frequency and most of the hardware and software part is allready certified. Some transponder manufacturers did the right thing (such as Trig) to support ADS-B out as a standard feature.
The receiver boxes are internet-interconnected and that is how they work out the position. It’s a bit like sferics are done.
They even work for some Mode C traffic, apparently.
One guy I know can see me from 100nm away on his box.
But unless there is a tangible benefit to somebody in having ADS-B, nobody is going to spend the money. Look at Mode S. Tangible benefit to GA = zero. In the USA, they used TIS as the carrot. In Europe, they just did it the European way: they mandated it. Very few people have active TAS/TCAS systems like I have, and none of them are going to spend the inevitable few k on having it upgraded to show ADS-B targets. And on past record virtually nobody in light GA is going to spend any money to make themselves visible on TAS/TCAS (by installing a transponder) so they are just as unlikely to put in ADS-B for that reason. So, all I can see is it being mandated one day, say 2020-2025, for IFR in CAS, but there will be zero benefit to GA.
Why would he not be allowed? What is the legal basis?
ICAO rules on ATC. Also trade unions will make damn sure that nobody waters down the rules so that someone who is not a radar qualified ATCO can offer traffic information / traffic separation.
The receiver boxes are internet-interconnected and that is how they work out the position. It’s a bit like sferics are done.
This is not accurate at all, as it has all to do with propagation of the signals. ADS-B has the advantage of being very accurate.
The benefits are quite clear, only you don’t seem to want to see them? It is a TAS system with better accuracy then anything before with just a small amount of money.
TIS will give way to ADS-B in the US as well, as TIS requires ground stations and more expensive infrastructure etc. You must be under coverage of the ground station for TIS to work. While ADS-B will work anywhere.
It is important that their are two different systems: ADS-B OUT: which is possible with a GPS and MOST transponders. Trig TT-21, TT31, Garrecht VT-01, VT-02, VT-2000, Filser/Funkwerk TRT-800 all support ADS-B out as a standard. Garmin only supports is with the GTX-330ES a quite expensive update, GTX-328 won’t do ADS-B and won’t be upgradable. Trig and Garrecht give good value for money, especially for ADS-B.
ADS-B OUT will get mandate for sure.
ADS-B IN is the receiver, to receive other traffic yourself. This will be much more affordable as Mooney Driver also seems to know, than a expensive system such as the Avidyne or Garmin TAS systems.
A better TAS systems for a low price, A huge benefit if you ask me.
ICAO rules on ATC. Also trade unions will make damn sure that nobody waters down the rules so that someone who is not a radar qualified ATCO can offer traffic information / traffic separation.
You don’t need exta ATCers on small airfields. ADS-B is just like your Avidyne TAS system, but better. You are aware of other traffic, so you will make sure you keep enough separation yourself. Just like you would use your current TAS system.
Interesting stuff.
Ok, so what do I need to have ADS-B IN (so I can see other ADS-B traffic on my 430w), and pump ADS-B out? I have a GTX330, probably not ES, and a Garmin 430W….i.e. easiest and cheapest way to do it.
Is the GTX330 worth anything second hand if the best way is to change the txpdr?
Thanks all…
Alan, an upgrade to ES is cheaper than a new ES txpdr as most of it is the same.
ADS-B out is txpdr based.
ADS-B in can either come from a proper traffic system (eg Honeywell or Avidyne or Garmin but most need an upgrade to work with it). This is because current TAS systems work by seeing the txpdr output and guesing direction and diatance. Because they receive transponder bursts they can also receive ABS-B transmissions if listening on the right frequency.
But as the ADS-B includes position it can also work with just a simple tuned receiver. This is why in the US you can currently get ADS-B in on your iPad with a small antenna.
Essentially in and out are unrelated.
