Hi all,
It seems that the wrong altitude reading is not related to BendixKing KT74 transponder. It is more likely to be related how 100 ft increment transponder encoding is decoded by F-receivers.
The conversation related to this problem is continuing in "Mode-S-Beast-and-Transponder-Mouse" Forum.
See here http://forum.flightradar24.com/threa...ceiver-problem
-mohair
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Question related to BendixKing KT 74 Transponder versus FR24
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Not sure if this helps your case, but i got a bad reading today also:
http://x264.nl/dump/dlh408-2014-04-08--775-feet.jpg Airbus A340.
This is VRS 2.0.2 connected to the FR24 receiver's raw port.
Edit:
And another issue on the website:
This should be callsign: QAF9 and reg: A7-AAH.Last edited by Jarod; 2014-04-08, 11:22.
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There are many other light aircraft which are temporary indicating 0 ft altitude in FR24. Have a look at these examples:
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If you know what type of ADS-B transponder these aircraft are using, let me know.
ATC is happy with my BendixKing KT 74 transponder. But FR24 is temporary indicating 0 ft altitude.
Here is my aircraft FR24 history
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There are no similar problems with airliners which are typically using enhanced surveillance S-mode transponders.
Is the problem related to elementary surveillance S-mode ADS-B transponders?
Is there a software bug in ADS-B receivers?
-mohairLast edited by mohair; 2014-04-08, 19:59.
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Hi all,
I begin to get solid reception from N446MM on 5.4.2014 starting around FL100 and made some replay from stored AVR formatted datastream. During rest of the flight down to Malmi airport, altitude indications looks like to be correct without any strange anomalies. Also during that same part of flight when FR24 is displaying 0ft. I have had previously some interesting altitude error indications for this same plane, but these are related to one software tool which creates different kind user defined outputs from source stream AVR, Beast etc. etc. Altitude errors are only visible when using some specific outputs. So, some kind of software problem can be also reason for that.
But anyway, interesting is that these errors are only seen when data is coming from N446MM. I haven't noticed that same phenomenon for any other commercial and general aviation flights inside my reception coverage area. That is something which is quite strange, I would personally expect similar errors to be displayed also for many other planes. I still have to try find out what would be the root cause for this one.
Just to add... Looks like Virtual Radar Server (VRS) is providing proper altitude indications for N446MM, when VRS is connected to that Beast raw output.
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F-EFHK2
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Originally posted by speedbird1960 View PostThere does seem to be some sort of altitude error, on Playback dated 5/4/14/ when you where approaching Helsinki Malmi, your Aircraft was showing Altitude 11,200 ft / Vertical Speed +1920 fpm when should have been showing -1920 fpm as it was descending.
Playback: http://www.flightradar24.com/2014-04...N446MM/30bf7f2
As an electronics engineer I think this can be related to the clock/timing margins of the FR24 receivers and the clock/timing of my KT 74 transponder asynchronous data.
On the other hand ATC is happy with my KT 74 transponder.
Are there are any FR24 hardware guys who could comment my findings?Last edited by mohair; 2014-04-06, 20:12.
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There does seem to be some sort of altitude error, on Playback dated 5/4/14/ when you where approaching Helsinki Malmi, your Aircraft was showing Altitude 11,200 ft / Vertical Speed +1920 fpm when should have been showing -1920 fpm as it was descending.
Playback: http://www.flightradar24.com/2014-04...N446MM/30bf7f2
Flightradar24 has good coverage in the Helsinki area, they have even got coverage on MLAT down to about 3500 feet.
Looking at the data on the Map and taking into account other Aircraft near your Aircraft had no errors, i would say its possible your Aircraft has an intermittent Transponder fault, maybe keep an eye on future playbacks of your Aircraft to see if it happens again, you can then make a decision on whether you need to get it checked.
Have a read of this article, as it explains about some altitude errors that can occur with Mode-S, its too technical for me to understand.
Last edited by speedbird1960; 2014-04-06, 20:15.
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Originally posted by speedbird1960 View PostI have just added your Aircraft to the Database, i will do some checks to see what i can find.
Centre Map over Finland before you start Playback: http://www.flightradar24.com/data/ai...446mm/#30bf7f2
Thanks for the database update, it looks fine now!Last edited by mohair; 2014-04-06, 19:30.
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Originally posted by F-EGLF1 View PostIt is probably not you, you are probably passing over an area with poor reception and the feeder is only getting partial data, I don't know how the server handles this, but I would not be surprised if it just based your heading and speed on the last valid data to stop you dropping off the display altogether but does not do the same for altitude.
Hopefully one of the admins can provide a fuller explanation.
What happens if you make a turn or change speed while you are showing 0ft?
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Originally posted by mohair View PostMy Mode-S code is A56206
Ps. See also my post to update aircraft information in FR24 database.
Centre Map over Finland before you start Playback: http://www.flightradar24.com/data/ai...446mm/#30bf7f2
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Originally posted by mohair View PostHello,
Hopefully this is the right place to put this.
I have a brand new BendixKing KT 74 ADS-B transponder installed in my private aircraft.
Everything works fine, ATC is happy and my aircraft can be seen in FR24.
But occasionally FR24 is indicating 0 ft altitude for several minutes although I am at high altitude.
- The transponder passed all tests with a transponder tester
- The transpoder display is indicating correct altitude all the time during flights
Do you know anything related to this problem with BendixKing KT 74 transponder and FR24?
- mohair
Hopefully one of the admins can provide a fuller explanation.
What happens if you make a turn or change speed while you are showing 0ft?
Leave a comment:
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Originally posted by mohair View PostHello,
Hopefully this is the right place to put this.
I have a brand new BendixKing KT 74 ADS-B transponder installed in my private aircraft.
Everything works fine, ATC is happy and my aircraft can be seen in FR24.
But occasionally FR24 is indicating 0 ft altitude for several minutes although I am at high altitude.
- The transponder passed all tests with a transponder tester
- The transpoder display is indicating correct altitude all the time during flights
Do you know anything related to this problem with BendixKing KT 74 transponder and FR24?
- mohairLast edited by speedbird1960; 2014-04-06, 18:33.
Leave a comment:
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Question related to BendixKing KT 74 Transponder versus FR24
Hello,
Hopefully this is the right place to put this.
I have a brand new BendixKing KT 74 ADS-B transponder installed in my private aircraft.
Everything works fine, ATC is happy and my aircraft can be seen in FR24.
But occasionally FR24 is indicating 0 ft altitude for several minutes although I am at high altitude.
- The transponder passed all tests with a transponder tester
- The transpoder display is indicating correct altitude all the time during flights
Do you know anything related to this problem with BendixKing KT 74 transponder and FR24?
- mohairLast edited by mohair; 2014-04-06, 18:01.Tags: None
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