Aircraft not being tracked?

Hello all! I'm newish to ADSB Exchange, but have been feeding on various other platforms since around 2017. I just recently setup 3 feeders for ADSB Exchange.

I work for a flight school in my city, and setup a feeder at our school on the airport field. When our aircraft are in the circuit, or even close to the receiver I am not picking them up on ADSB. They are all Mode C transponders on Canadian Registered aircraft. I know they are within line of sight of the antennae.

Any ideas on how/what is happening? I know the aircraft are in the air because usually I am the ones dispatching them/instructing students to leave the Transponder on ALT Encoding setting to allow for tracking. Cheers!

TJ

 

This is just a theory, I am no coder: When tracking planes by Squawk code for a given position (which is known because MLAT calculated a signal at that position), wouldn´t it be possible to track Squawk changes at that position, irrespectively of duplicate Squawk elsewhere? Basically, give the signal location a UUID and log all Squawk codes that appear at the tracked signal location. Mark it as "unreliable", include it as an option, a layer, to be turned on and off by useres who don´t want the occasional trouble of jumping MODE A/C signals on the map.

Point is: In Europe, NATO seems to distort and sabotage any MODE S MLAT transparency by switching off their MODE S transponders. As I understand that is exactly the reply given by ADSBX to take-down letters by the militaries of the world, sent to ADSBX, the last standing military MODE S tracker that is uncensored. Now, it seems that message has reached the top brass in Germany. Bundeswehr jets started to disguise by switching off MODE S with a notable drastic loss of tracking around July 2020 and ever since. They claim they do it because the Russians should not monitor their sophisticated patterns of dropping an atomic bomb - a pattern that is routinely trained over the north east of Germany. Military air training patterns over Germany can be heard routinely in about two third of its territory nowadays, with a continuing upwards trend. Clearly we are heading back to Cold War levels of simulated air warfare, right above densely populated European countries. And - as if Russia relied on MODE S MLAT tracking… So, this measure is in the face of transparency for citizens. And apparently it´s being deployed in other countries in Europe as well. We heard from Denmark here in the forum where exactly the same thing happens.

I am running receivers in ADSBX in order to contribute to transparency on military air noise in a given area. Unfortunately that is pretty much all I can do, practically, to help out the community, as I don´t have the skills to code a MODE A/C patch for the MLAT server. But I am sure there is a technical way to mitigate the MODE A/C game for our project here. Even though certainly, it wouldn´t be perfect in the beginning. But ADSBX grew exactly from these challenges.

 

Gee, Wiedehopf, what´s with the aggressive address? I was merely writing a contribution to the discussion. Of course I am aware that you are the one who keeps this thing working here, technically. And of course no MODE AC MLAT will ever materialize without you coding it. I am totally aware. I would contribute actual code if I could. But I can´t. I am just a little feeder, feeding to ADSBX for years, partly fedding ASDBX exlusively - maybe that´s "too less" to partake in discussions here in ADSBX forum, I don´t know. So, chill, please, nobody is questioning your expertise, prominent and foremost position in this co-op. We are on the same side I am not claiming to be able to actually code a solution, I was trying to add a theoretical thought in order to come up with a solution for a lately developing actual shortfall of ADSBX´s overall actual coverage. And I am sure a lot of folks around here do actually follow, what I mean and would probably see it as welcome evolution of ADSBX, to keep pace with the transparency-wrecking methods of the military. Another question is whether you have any resources to come up with a solution at any point in the future.

Sure, the growing-from-challenges-phrase was a bit silly. It was rather referring to ADSBX´s popularity with the general public due to ADSBX´s non-censorship of military flight, it was not so much meant as parroting free-market-bs-speech. My apologies for the miss-phrasing that triggered unnecessary reply-work at your end.

Now, with the military going dark with turning off MODE S, it´s just natural to think of a mitigation. Because ADSBX just lost MLAT capability for a huge portion of relevant (or interesting) military flights in certain areas, as far as I can tell. I think that is a problem for transparency that we all rely on in our free societies and that sets us apart from opaque regimes.

Not sure what you mean with ModeC not even being used. I am referring to

PiAware:
view1090-fa --metric --modeac

ADSBX image:
/usr/bin/viewadsb --modeac --metric

Both give you an opportunity to activate MODE A/C and give you an option to see a textual listing of all AC in range. (In fact, MODE AC was activated in the default setting of both feeder images, PiAware and ADSBX - so no need to actually activate that first).
Do fighter jets use military transponders? You bet. Would be funny if they didn´t. Is it non-MODE AC? I don´t know. It certainly a logical pattern of Squawk sequences and the little bit of decoded signal correlates to the MODE S portion of their flights. Maybe you have more insights here than I do. I am not a military freak. I want to ensure basic transparency for the victims of militarization - and the solution happens to be public MLAT of fighter jets. It´s the only way to hold the military brass accountable and you can actually go with that to your representative and try to remind them that we are not in a war zone and we do actually approve of a free wheeling airforce. When you have not MLAT, you have no proof, unless you happen to get your camera ready at the right plane at the right second. And that´s why they switched off MODE S. Not because of "the Russians".

Military jets here in the area start with MODE S active from their respective bases. You can see the SQUAWK and the ICAO#. Then they switch off MODE S, as soon as they start war simulation patterns. But you could already isolate them in the text listing. A training-team of jets will usually have a Squawk sequence, counting up the last digit of the Squawk by one. In the MODE section, it says AC or A. You can actually observe the change of Squawk for the identified Aircraft because most of them do actually show an altitude, strangely. Also, the MODE AC aircraft will be listed at the bottom of the list. At least in these regions, there are not many aircraft left that fly around without MODE S at least. So there is a high probability that you will not lose track of the aircraft in the text listing. At some points throughout a training pattern, one of the pack will "de-cloak" briefly - for whatever reason, it becomes visible in MODE S MLAT. That is when you can actually check what Squawk it has and whether you are still looking at the correct instance in the textual listing.

This method is prone to failure of course and it´s tedious manual - so basically useless. It only has an effective useful meaning when the range of the receiver is fairly small and well known, so that you can actually work out a trend for a given region. But I thought it shows a pattern that could be somehow translated into automatization and incorporated into MLAT. Of course, the MLAT server is always overloaded! I know. It´s seems to be the main plague of MLAT. I didn´t say it needs to be done by you. That´s why I post it in this forum, perhaps somebody else comes up with a solution. Most certainly I am not gonna try and start my own MLAT network

 

I can´t edit the post, so I do it here. There is a misplaced "not" here. It should say:

"(…) we do *not* actually approve of a free wheeling airforce. When you have MLAT (…)"