Primarily for general aviation discussion, but other aviation topics are also welcome.
gyrotyro wrote:I asked my wife to track my flight today on FR24. It did not show up.

I have a Becker mode S transponder and PAW Rosetta both working.

Should FR24 pick up my mode S transmissions automatically?

Any tips please?


So that's just one flight? Have you looked at the history of flights of your a/c?
My aircraft only has a bog standard Garmin 330 mode S transponder - and it is displayed on FR24 99% of the time.

However I’ve recently been in touch with the FR24 Customer Help Desk. I queried why FR24 show my (and most White Waltham based ) aircraft as landing at either Wycombe or Blackbushe - why did it not show them landing at Waltham?

Answer : FR24’s database of airfields only recognises airfields that have both an ICAO AND an IATA (airline) identifier.

This is why it often lists either “Unknown” or a wrong airfield for takeoff / landing. It finds the nearest that is in their database.
PaulSS liked this
gyrotyro wrote:Having now had a chat with the helpful guys at LX Avionics it transpires that the reason that my aircraft doesn't show on FR24 is that it is not connected to a GPS.


That's not right.

Connecting your transponder to GPS would provide ADSB out (assuming capability), which FR24 can display.

But FR24 will happily use mode S only (I.e transponder not connected to GPS), assuming it's picked up by 3 or more receivers.

I don't have ADSB, I'm picked up by FR24.
Miscellaneous, Iceman liked this
I flew in the UK with new mode S for one year before I discovered that transponder callsign ID differs from aircraft registration (aircraft reg has 1=One while transponder radiated I=India, I was told the avionics guy lost his medical 15 years ago :mrgreen: ), this was spotted by Pentoise ATC in France along with "you are mode-S identified with wrong ID", it seems UK ATC never cared about that :lol:

Try searching FR24 with transponder HEX code (you can get it on GINFO or N-Number Inquiries), then you maybe be able to find your trace with a dodgy callsign :thumleft:
Last edited by BehyBill on Mon Sep 09, 2019 9:24 pm, edited 2 times in total.
@gyrotyro IF your Becker Mode S transponder has an extended squitter, why not run an FTDI cable from one of your Rosetta USB sockets to the transponder and have ADSB Out?

In summary:

(a)Only ATC can guarantee to see your Mode S by interrogating it and receiving a reply i.e. doing what it was designed for. ATC don't share that information with the likes of FR24.
(b)FR24 (and similar) can only see your Mode S by triangulating your position (multilateration) once you're seen by 3 or more ground stations. These are generally 'volunteer' stations, so there's no guarantee of their location and they're not necessarily going to see you at low level or when you're hidden by hills etc.
(c)Sometimes FR24 need your specific aircraft in their database to show you on their website. This isn't always the case and does seem to be random. If you want to better your chances then register your aircraft with them.
(d)You stand a FAR better chance of being seen by FR24 etc if you have ADSB Out, which is easy to do if your transponder has an extended squitter.
(e)PAW is not seen by FR24.