missing Sqwack

[dor4x]

Hi

I am hardly getting Squack information from teh aircarfts. All other data in including good tracking is avalible.

Is squack only avalible in so few aircrafts in thier ads-b?

[AirNav Support]

Squawk is not in the ADS-B message.

Squawk is sent out over Mode-S when an aircraft is interegrated by a Radar site. If you don't have a Mode-S Radar site near by you won't get squawks.

[dor4x]

Thanks for your reply.

Yesterday afternoon I suddenly got squawk info for all aircrafts. Since then (next boot) I can't recreate it, so I was sure it is somwthing with posioning the antenna or something like this.

[dor4x]

Hi
I am probably missing something..
So Squawk is not part of the ADS-B message. So how come I am getting Squawk info for some flights only?
It should ALL or NONE, isn't it?

[RodBearden]

Dor4x

RadarBox receives Mode-S transmissions as well as ADS-B. The squawk comes from the Mode-S. All aircraft that transmit ADS-B also broadcast Mode-S, but not all aircraft that transmit Mode-S broadcast ADS-B.

Hope that makes sense!

Rod

[dor4x]

All aircraft that transmit ADS-B also broadcast Mode-S

So in this case all ADS-B aircrafts that I can track their poison are transmitting Mode-S too?
So all ADS-B aircrafts should have squawk information too, isn't it?

I am getting squawk info regardless of ADS-B. Most of my Squawk info are for non ADS-B aircrafts.

Screen shot attached

Thanks

[DaveReid]

So in this case all ADS-B aircrafts that I can track their poison are transmitting Mode-S too?
So all ADS-B aircrafts should have squawk information too, isn't it?

I am getting squawk info regardless of ADS-B. Most of my Squawk info are for non ADS-B aircrafts.

The presence, or absence, of a squawk on the display has nothing to do with whether an aircraft has ADS-B.  As already mentioned, you will only see a squawk if the aircraft has being interrogated by a Mode S ground radar.  That applies equally whether an aircraft is ADS-B-equipped or not.

End of story.

[dor4x]

Ok..

Squawk is send via ground station, right?
Shouldn't this info be available to me all time or never?
Why just part of the time on some aircrafts?

Thanks!

[Allocator]

Ok..

Squawk is send via ground station, right?
Shouldn't this info be available to me all time or never?
Why just part of the time on some aircrafts?

Thanks!

No, not quite.  The aircraft is fitted with a Mode S box (transponder) that listens for a signal from the ground.  When that signal is sent from the ground station (tell me who you are), the equipment in the aircraft responds (this is me).  So, no signal from the ground means no answer from the aircraft.

[dor4x]

Got it!
Thanks!

[Allocator]

My pleasure.  I'm sure that somebody could come up with a much more technical answer, but it does give you the basic idea :-)

I'm very lucky here in the UK, as almost all the squawks show up.

[DaveReid]

My pleasure.  I'm sure that somebody could come up with a much more technical answer, but it does give you the basic idea :-)

In non-techie-speak, the ground station sends three main types of interrogation:

a)   (broadcast to any aircraft that can pick it up) who's out there? - all aircraft that haven't yet established contact with the ground station reply, sending their Mode S codes

b)  (send to a specific aircraft) what's your Mode A squawk? - the aircraft concerned replies with the squawk, which allows ATC to tie up the radar return with a specific flight plan

c)  (sent to a specific aircraft) what's your Mode C altitude? - the aircraft concerned replies with its altitude

HTH
Dave

[DaveReid]

I'm very lucky here in the UK, as almost all the squawks show up.

Interesting screenshot - I've had DA42 G-SELC without a squawk too on many occasions, although it sends altitude most of the time.

Never seen it as high as FL290 though, something not quite right there ...

[Allocator]

I find that sometimes the altitude readout takes a few "hits" to settle down.  If I get a wild readout like this, I just wait a couple of seconds and it usually give a sensible reading.

I'm running Beta software at the moment too, and I'm not entirely sure what version I have, so all bets are off :-)

Edit: On the other hand, I suppose that it is possible that the aircraft might just achieve that altitude? Maybe not.

performance
Cruising speed at 95% power at 12,000ft 376km/h (203kt)
economical cruising speed 334km/h (180kt)
Initial rate of climb 1700ft/min
Max operating altitude 20,000ft
Range at 60% power with standard fuel 1912km (1061nm), with optional fuel tanks 2677km (1485nm)

[DaveReid]

Edit: On the other hand, I suppose that it is possible that the aircraft might just achieve that altitude? Maybe not.

Assuming that the screenshot is from earlier today, I had G-SELC from 08:39 to 09:07, descending from 8975' to 2465', and then 10:17-10:24 climbing from 1350' to 1600'.

The DA42's Type Certificate gives its max operating altitude as 18,000ft.