FlightAware Discussions


Hi all, in the statistics page when I check my details I see a column called OTHER (1090MHZ ) Mode S.

Can anyone explain this number to me as my OTHER numbers seem to be low most of the time. I understand the stats for ADSB and MLAT . I see many people with much higher OTHER numbers and I wonder why… My setup gives me great coverage in most directions up to 200 NM…Thanks for any information… Nick

It is explained in this older newsletter.


Thanks for that. Cheers.

As quoted…

The primary reason why a message would be classified this way in Skyview or on the My ADS-B statistics page is because the message was not an ADS-B position message and it was not received by enough sites at the exact same time to be used for MLAT purposes.

Can I assume that when the aircraft is on the ground and/or taxing with transponder in standby its being classified as other. The reason I ask is because it seems that people that are close to an airport have much higher numbers when it comes to OTHER…

So if this taxing aircraft or unidentified aircraft then takes off is identified by transponder ( now in ON mode) and then gets counted as ADSB aircraft, ie the same plane counted twice, once under other and once under ADSB… am I on the right track with this thought… Thankyou for your help…

It’s more likely that they are non-ADS-B aircraft and mlat is ineffective because few receivers can see the aircraft when it’s on the ground. ADS-B aircraft do transmit positions when on the ground.

Aircraft are not double-counted (within a single day) - a given aircraft falls into only one category. If a given aircraft has no position information for a while, then we start hearing ADS-B or mlat positions, then that aircraft is counted as ADS-B or mlat, not “other”.

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OK This is an interesting observation as I too have had a close look at very high ranking stations and it definitely does seem to correlate that stations very close to an airport always seem to have a very high OTHER Count, this then pushes their rating higher to a point that a station very nearby to the same airport but does not receive the ground transmission can NEVER match the or surpass that stations rating.

I personally feel there is something wrong in the aircraft count when moving from OTHER to MLAT/ADSB Status and a great possibility they may be getting doubled up.

Flightaware, Can you tell us if the ICAO Code is the common key for an Aircraft count.
Maybe we could put this to a real observation test.

Can you supply a small snippet of example data to show an aircraft that has moved from OTHER to MLAT/ADSB.

To be quite honest the OTHER Aircraft are fine to be counted as it is a received data packet but it should not contribute to a stations rating because at the end of the day ratings should directly correlate to a station contribution to tracking an Aircraft. i.e. put a position report on a map for another users to observe the received aircrafts position.

After all this is about Aircraft tracking not how many packets are received by a station. Therfore the OTHER Aircraft simply do not count, for all we care they could be cars driving past with transponders in them in STBY mode, the data from these transmissions is useless to us and pointless to the whole system.

Here is a quote from your own page:

Want to improve your ranking? Make sure your feeder and network is running 24/7/365. Then, you can either add more sites (e.g., at home in addition to the office, at a vacation house, at a friend’s house, etc.) or improve your reception. To improve your country’s ranking, recruit colleagues or friends to submit their data to FlightAware. Create or join a flight crew so that you can collaborate with others.

This does not say anything about having a line of site view to an airport which seems to have a dramatic effect on a stations statistics and rating. Just go and take a look at some of the top ranking stations and tell me otherwise.

I have seen stations that have quite a huge range > 250Nm, myself included, that would see all the same traffic coming out of surrounding airports that cannot beat the stats of a station that has a rather poor reception coverage but obviously a perfect reception of ground traffic at the same airports.

The data just does not correlate making the ranking system unfair to some degree and there are people that chase these stats, but they are against stations they could never possibly beat due to the OTHER aircraft factor and the simple fact they live in line of sight view of an airport…

I am not one for chasing these statistics but I have quite a good station with very good coverage than the average one and looking at stats on a daily basis it does not add up to me.

It took me some time to understand why poor coverage stations can get such a high ranking, think this through a little bit Flightaware, it maybe something that has just never been bought to your attention.

That’s my 2c worth on the matter.

Cheers Glenn.


I’m not sure what you want to see here.

This is mostly a discussion about “what should the ranking mean” and there have been long and unproductive arguments in the past about what it “should” be. There’s no particularly perfect metric here.

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So how can I get my OTHER count to go up, any suggestions…apart from moving next to the airport cause most people with high OTHER numbers are near by an airport and their reception range rings are no where near as good as mine…

The Metric is quite simple, Only Count Aircraft for ranking that give us a position report that can be plotted not Aircraft that just send a data packet that means nothing.

Its fine to show the OTHER Aircraft counts but do not include them in the ranking calculation, this would be a much fairer system to others that live far away from any airport.

Cheers Glenn.

Personally, I like to keep my ‘other’ count as low as possible.

Looking at your FA stats page, 98% of the aircraft you receive are within 50nm so I’m not sure what you mean.

I could very easily inflate my ‘other’ stats if i wanted to - Make the filter on my receiver more permissive, and turn off verbatim reporting. This results in hundreds of bogus messages being generated that contain no useful data, but would massively inflate the number of supposed aircraft seen in my stats.

This is completely pointless however, since the only data that is useful is that from valid aircraft containing position data, or used for mlat calculations. There are some aircraft that fall into this category, but they should be a small proportion for most people.

Personally, I think that FA should make their stats counter more strict - increase the number of messages from a particular hex code before it is counted. This would remove the ridiculous numbers that appear on some sites, where they apparently have thousands of no position aircraft per day. It’s just a meaningless number in that case.

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So how many messages from a hex code before its counted in the system… others or otherwise…

Caius, Thankyou, you are on the money…

That is something I have also observed, if my receivers are unfiltered and I get heaps of bad decodes from clipping the OTHER count goes through the roof.

This brings me back to my point of the ranking is definitely not a true measurement of station performance. The ranking is also not important what matters is USEFUL data should only be counted.i.e ADSB/MLAT/UAT and that is all.

The Flightaware systems numbers are truly over inflated with useless data counts as you have pointed out.

Keithma, I think you are looking at my Short range station which has mostly reports under 40nM and confusing me with Nick2704.

I run two stations and my long range station has plenty of reports > 250nM and looking at Nick2704 he has plenty of reports up to 200nM.

Cheers Glenn.

I don’t know since FA haven’t said what their criteria are, as far as I’m aware. What I can say though is that my own monitoring counts an aircraft after 250 messages received, and FA stats always shows more aircraft than I count so I assume it’s more permissive than that.

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