Bendix King KT70 is mode S only, KT73 is also mode S but doesn’t list any TSO for ADS-B. The Garmin GTX328 doesn’t support ADSB and all the Garmin Mode S transponders require an upgrade to ES as it does not come standard. The Trig and its OEM variations all support ADS-B.
A flarm is much more useful though
Both flarm and ADS-B require a high density of users to be really usefull. Very crude / basically it is the same technology, flarm being less expensive as being non certified.
Flarm is extremely usefull for gliders and starting to get more and more usefull for motorised aircraft. This is because the system is widely adopted by gliders (as does ADS-B in the gliding world).
Look at marine, AIS (their version of ADS-B / Flarm) is widely adopted, and used as overlay on radar screens for example. The more people use these kind of systems, the more usefull they get. As the technology of these systems far exceeds the capabilities and posibilities of their radar variants it seems very clear that these new technologies are getting more and more important.
As indicated before, in the USA there are two different ADS-B systems, while in Europe only one, the 1090 MHz version. In the USA they also have UAT as possibility which does ADS-B while having a mode C transponder only.
As indicated before, in the USA there are two different ADS-B systems, while in Europe only one, the 1090 MHz version. In the USA they also have UAT as possibility which does ADS-B while having a mode C transponder only.
Does UAT require any kind of transponder? (Its a genuine question – I am no expert of this stuff)
It seems to me that the natural progression should be to implement ADS-B and then when its proven, to eliminate transponders from civilian ATC use. Radar is always going to be useful for the military and air defense, but that’s a different issue – invading aircraft don’t do it while squawking a special ‘invader code’.
I’d like to install UAT in 2020 and then hope at some point after that to clean up the panel by removing the (Mode C) transponder. Is that technically feasible with UAT, if regulation allowed it?
Does UAT require any kind of transponder? (Its a genuine question – I am no expert of this stuff)
Good question. From a technology point of view I don’t think so. I guess you are required to have a mode C transponder in the USA for some airspace, as long as that isn’t revoked I would also guess you would have to keep your mode C transponder. Not sure on this, as European I haven’t got anything to do with UAT. Maybe someone else can answer this.
Both flarm and ADS-B require a high density of users to be really usefull.
And there lies the problem. With good old Mode C, one end of the job is already in place.
Well, as much in place as anything will ever be in place, given the “non community participation as a default position” attitude prevalent in much of GA 
I just don’t see ADS-B ever being made mandatory for VFR OCAS.
And most (all?) of southern Europe has ignored Mode S anyway.
That is true for every new technology.
It applies to electrical cars as well for example. Before your can get good service at every corner of every street, there should be more users of the system. Most aircraft maintenance companies didn’t do diesel or Rotax engines, now you can get service for Diesel powered aircraft and Rotax powered aircraft about anywhere, as there are more and more aircraft using these technologies.
Yes, but both Rotax and Diesel engines offers some real tangible good points that the traditional engines don’t. Mode-S is not mandatory in Norway, but I was told to get one because ADS-B would some day become mandatory and ADS-B was only compatible with mode-s. Only they didn’t know exactly when. I don’t have any need for any of those technologies. A mode-s, ADS-B out capable transponder is only slightly more expensive than a mode C, so no big deal. It looks completely random too. Garmin has this mode-s transponder specially made for European VFR. The only thing special about it, is it has NO ADS-B out capability, and ADS-B out is the main reason for going to mode-s.
ADS-B out capability is only half of the equation, you also need to feed it with appropriate data. Such a device is nowhere to be found except in Boeing and Airbus’es.
Flarm I understand, that I have used, and it works. ADS-B is just something that feeds FR24 as far as I’m concerned.
the natural progression should be to implement ADS-B and then when its proven, to eliminate transponders from civilian ATC use
I am far from an expert on this matter, yet much curious. AFAIU, ADS-B means (in Europe):
-) transmitting on the same frequency as a transponder: 1090 MHz
-) transmitting more or less the same data as a mode-S transponder
-) in the same format as a mode-S transponder
-) without however requiring triggering from a ground station
If this is correct, implementing ADS-B is by far the easiest as a piggy-back function of a mode-S transponder. Those that exist (Trigg &c) seem to confirm this. So eliminating transponders would eliminate ADS-B, too.
What things look like on your side of the great pond, and what UAT stands for, I’ve no idea.
Garmin has this mode-s transponder specially made for European VFR.
Garmin did a strange thing in here. Basically the GTX-328 is a low power output version. Therefore it can not be used for aircraft flying over 18.000 Ft or cruising faster then 175 Kts. It has nothing to do with IFR/VFR. As long as an IFR aircraft is within this limitations, the GTX-328 can be used for both VFR and IFR.
ADS-B out capability is only half of the equation, you also need to feed it with appropriate data. Such a device is nowhere to be found except in Boeing and Airbus’es.
This is not true, one needs (for full compliance) a WAAS GPS. This can be the GNSx30W, IFDx40, GTNx50 versions. There are also some standalone GPS receivers, suchs as the one from Trig which can be used as position source.
ADS-B means (in Europe):
-) transmitting on the same frequency as a transponder: 1090 MHz
-) transmitting more or less the same data as a mode-S transponder
-) in the same format as a mode-S transponder
-) without however requiring triggering from a ground station
Almost correct Jan. ADS-B is additional data that is broadcasted as addition to the mode S signal.
Basically an ADS-B compatible mode S transponder does:
- Receive on 1030 MHz and Transmit on 1090 MHz.
- Replies to interrogations made on 1030 MHz by answering on 1090 MHz. This answering can be for any aircraft, or for a specific aircraft.
- Broadcast information at 1 sec intervals without interrogation from the ground station
- It transmits mode A (squawk code), mode C (pressure altitude) as mode S (selective information), this includes the aircraft ICAO adress (24 bit / 6 HEX code) and the aircraft tail number, maximum cruise speed.
- With ADS-B it also transmits extra data, suchs as GPS position, heading, speed etc. On airlines this includes far more information. Also included is the GPS integrity.
UAT is Universal Access Transceiver which operates on 978 MHz. It is a datalink on a seperate frequency (both in / out) and also adds the possibility to get data from ground stations.
