Peter wrote:
Some do, especially on longer flights
Very few gliders carry a transponder, even fewer for long flights (powering a Mode-S transponder for a diamond distance is problematic). Maybe 1 in 20 (and they will most likely be motor gliders). It’ll be FLARM fed in by the OGN for sure.
Sorry, yes, I meant Mode S.
I have seen plenty of gliders here in the UK, and I believe elsewhere, on my TAS605 system, but they could have been just Mode C.
I can’t see anybody installing Mode S when they can meet regulatory / ATC / conspicuity requirements with a Mode C box which doesn’t radiate their aircraft reg, is not visible on FR24, and which can be picked up on Ebay…
The OGN stream is fed into FlightRadar24. The OGN stream mainly has FLARM in it but there are also some stations picking up P3I (PilotAware)(mainly in Southern England).
Mode C is not enough to be on FR24. You need Mode S to allow multilateration.
Could also be that the gliders were on FR24 because they had Mode C transponders. Some do, especially on longer flights.
That data comes from the OGN (since FLARM is encrypted and its protocol secret, OGN receives FLARM and others and feeds them into various other things).
However, your reception of it on FR24 required internet access which is generally not assured when airborne. I think OGN are planning some kind of retransmission service which will at the very least work with the inexpensive PilotAware system, so PilotAware users will be able to see gliders as well as ADS-B and PilotAware devices.
Yesterday while flying with some friends and passing over La Roche sur Yon at around 3000 ft the AFIS advised that there were 3 gliders in the air and close by. The 2 sets of mark one eyeballs in the front seats eventually managed to spot one of the gliders before the passenger in the back announced he could see all 3 to the left of us on his smartphone. He was able to point out their exact location and we were able to identify all 3 looking outside. He was using the free version of Flight Radar. I have only ever used this app on the ground and assumed it only identified mode s transponders. I thought that most gliders in France equipped with Flarm not mode s.
However the accuracy of identifying these gliders was very impressive and I do wonder about the value of spending large sums on ADS B in or TCAS if you can do this with a smartphone and a free app.
arj1 wrote:
According to Mendelson’s (gps.co.uk) it costs £3114 to buy a GTX335 with a gps card vs. £2874 without. £240 savings?
I think in this comparison both versions provide ADS-B OUT, the difference is only whether the WAAS GPS is internal to the transponder or a separate unit.
If it were only new installations that were ADS-B mandatory (in my area of the US) I would never have installed a new transponder in my plane, and that is doubtless why FAA didn’t go in that direction. As it is, having just installed a new transponder etc my distaste for the manipulative and/or flaky people and processes associated with avionics is ever growing.
Peter wrote:
I am merely saying that if you look at what is being pushed in the UK, it isn’t certified ADS-B OUT.
I think it is both. I wouldn’t be surprised to see certified/non-certified position source ADS-B for general use and certified ADS-B required for certain airspace.
I don’t disagree 
I am merely saying that if you look at what is being pushed in the UK, it isn’t certified ADS-B OUT.
The CAA sounds (though I am not sure) like they are interested in promoting the various low cost approaches, but that can be only for inter-aircraft anti collision purposes. ATC (i.e. airspace compliance surveillance) will never be able to see that stuff. These two are very different objectives.
Peter, what I still don’t get is why not to say the same thing as for 8.33: any NEW transponder installed in G-REG from xxx date must be ADS-B OUT enabled.
It looks like it is getting hard now to buy a non-ADS-B OUT TXP these days as most manufacturers are aiming at the US hence ADS-B out.
According to Mendelson’s (gps.co.uk) it costs £3114 to buy a GTX335 with a gps card vs. £2874 without. £240 savings?
