Menu Sign In Contact FAQ
Banner
Welcome to our forums

How many homebuilts fly "high"?

Peter wrote:

A very good point, but Mode S is pretty well mandatory for “touring” in N Europe.

I would say “central Europe”, not “N Europe”…

ESKC (Uppsala/Sundbro), Sweden

Ha, here is another “low flyer” The speed and everything seems correct, does this mean he has ADS-B?

The elephant is the circulation
ENVA ENOP ENMO, Norway

I have just spotted an RV7, 7000, at zero feet altitude (Manchester area). Another data point disproving filtering of 7000 squawks.

The speed and everything seems correct, does this mean he has ADS-B?

I wonder what sort of ADS-B OUT implementation you could have in a Lancair 320? It does need to be certified (radiating equipment) even on a homebuilt, so not cheap. Also why do it? There are incentives for homebuilts to not radiate too much (due to the required overflight permits, and other factors like limits on long term residence). If I had a homebuilt I would without question have Mode C and use it 100% of the time (for TCAS visibility) but no more; Mode S as required by airspace only.

But you cannot turn off the Mode S radiation if the TXP is on at all. You can turn off the Mode C and fly Mode A only but that is a stupid way to fly and useful only if you want to bust airspace from underneath, but they will still see your Mode S data.

Also, the speed is ground speed so you could see wildly varying values, which will look “right” by accident a lot of the time.

Administrator
Shoreham EGKA, United Kingdom

Peter wrote:

I am looking now at a PA28-235, squawking 7000! Flying at 6600ft near Lausanne. So FR24 doesn’t simply drop 7000 squawks. Probably the reason people think it filters out 7000 is because it filters out by some minimum altitude IF it is one of the popular types.

I don’t think they do, it is probably because they lack reception in that area for low altitudes. They do triangulation for non ADS-B and FR24 simply don’t have coverage for the needed number of antennas below X feet. Here in southernmost Sweden we have lots of FR24 receivers (I have one in the attic) which means that flights from 1300-1500ft is visible.

To me the obvious Q is why say the south east UK is not covered with 7000-squawking aircraft, given that the terrain is flat and some have appeared on FR24 at low levels.

If you set up an alert for all of Europe, PA28-161 for example, you should see large numbers of them. But only maybe one per hour appears.

Another thing is that the FR24 website is very different to their phone app and the alerts you can set up on that. For example, this should show my two flights EGKA-LFAT and back but it shows nothing, yet the FR24 app on the Samsung S6 showed both of them. But even the app shows far less traffic than I would expect.

Administrator
Shoreham EGKA, United Kingdom

Notwithstanding the multilateration receiver density issues mentioned by martin-esmi, I suspect that in the wider GA fleet there is a lack of Mode-S transponders. A quick look in my hangar reveals < 20% adoption. Needless to say, these are the going places machines. None of the non-complex aircraft have one.

@Peter – I’m surprised that you haven’t bought yourself a Mode-S receiver like the Kinetic SBS or Airnav Radarbox. Then you would see first-hand exactly what’s going on and what FR24 is filtering.

EGTT, The London FIR

Finners wrote:

A quick look in my hangar reveals < 20% adoption

It looks to me that this is a UK phenomenon. The hangars I have access to have 100% (or very close) adoption rate, nowadays even training aircraft or motorgliders have Mode-S. With Mode-C only, you’re quite limited airspace access wise on the continent.

LSZK, Switzerland

I’m surprised that you haven’t bought yourself a Mode-S receiver like the Kinetic SBS or Airnav Radarbox. Then you would see first-hand exactly what’s going on and what FR24 is filtering.

However, AIUI, that would give me only my local data, not access to the whole FR24 data feed. But to be honest I am not that much into this It’s just interesting to see flying patterns. This has implications for IFR, etc.

Administrator
Shoreham EGKA, United Kingdom

That’s true Peter, you would only get your local data, based on the line of sight from your antenna. It would be more than enough to detect anything flying at 1,000 feet within a 40-50 mile radius.

Another option would be to download Planeplotter which offers a similar service to FR24, i.e. you don’t need any hardware – but is less pretty and requires a bit of setting up. You can request a free 21 day “Master User” trial which will give you access to the multi-lateration feature and, as far as I am aware, the full data feed from other users.

EGTT, The London FIR

That would be FLARM, however, not ADS-B. Does FR24 pick up FLARM?

FLARM transmission are encrypted (it’s a closed system), however the Open Glider Network Project has cracked that and designed low cost ground receivers which feed their own servers and also feed into FR24. The ground receivers are based on Raspberry Pi or similar hardware with open source software. They also operate a self-registration database so glider pilots can provide details of their aircraft to be shared with the track logs. Tracking data is also accessible via various OGN websites.

FlyerDavidUK, PPL & IR Instructor
EGBJ, United Kingdom
Sign in to add your message

Back to Top