Radarbox is "blind" for the planes above my head

[Mike_Tassy]

Do the targets show as having a position?

Hi, there is a globe next to the entry in myflights up until it enters my no go zone, the globe dissappears, and the lat / long dissappears from the end of the flight s details.  All the time though, the aircraft is still in myflights and is still being updated with mode-s - just not with lat / long and therefore not on the map.  It all reappears going out the other side. 
There were a couple of posts earlier in this section with people having the same problem, others may have the same problem and dont know it till it is  pointed out.  I wonder how many have just accepted this as "being down to my location" or "just my antenna"

Mike

[DaveReid]

Hi I have had my network going today and I also have a plot from planeplotter with a few hours worth.  The red circle is where I cannot receive any plots, although the aircraft remain in the list of mode-s and are continually updated, then reappear on the map when going out the opposite direction.   My receive range is good, I can get up to the nsw / vic border most times.

Is it only lat/lon that you lose, or do you stop getting groundspeed and track updates as well?

If the latter, I would suspect that for some reason 112-bit ADS-B packets are being lost, whereas 56-bit Mode S packets are being processed successfully.

[airdata]

Hi Folks.  Well yes I had the problem with my radarbox in Auckland, New Zealand.  I recently sent it back and today I got it back.  A note mentioned that a new circuitboard was soldered in.  It is however the same original RB unit.  Sadly, the problem that I have of a very large rectangular area with no coverage remains.  My topic was here: http://www.airnavsystems.com/forum/index.php?topic=3452.0

So this issue remains.  The symptoms are the same as posted in this thread.

Any ideas??

[Mike_Tassy]

Hi David, I only lose lat/long from the aircraft in Myflights.  When you scroll across to the end of the aircraft, everything is there except lat/long.   I watched a flight today taking particular note of this.  When the lat/long dissapears from the list it drops off the map and the globe dissapears. Its as if it loses the ADS-B part of the messages but the mode-s is still populated for the entire flight
Mike

[bratters]

Hi David, I only lose lat/long from the aircraft in Myflights.  When you scroll across to the end of the aircraft, everything is there except lat/long.   I watched a flight today taking particular note of this.  When the lat/long dissapears from the list it drops off the map and the globe dissapears. Its as if it loses the ADS-B part of the messages but the mode-s is still populated for the entire flight
Mike

A break in postional data sounds more like transmission interruption than reception problem?

[Fenris]

Hi David, I only lose lat/long from the aircraft in Myflights.  When you scroll across to the end of the aircraft, everything is there except lat/long.   I watched a flight today taking particular note of this.  When the lat/long dissapears from the list it drops off the map and the globe dissapears. Its as if it loses the ADS-B part of the messages but the mode-s is still populated for the entire flight

Hmm, so you are saying that *only* lat/long disappears, if you still have GS and heading then the 112 bit packets are being received.

Can you capture some port 30003 output? Telnet should do it, then you can paste a bit here and no doubt Dave Reid can pronounce.

There is also a way of capturing the USB data, Google for USB Logger, it's freeware. That should then be definitive as to whether the correct bit pattern is received, each bit comes over USB as a byte where the bits are 8MHz samples with 00001111 and 11110000 as representations of the possible uncorrupted data bits.

[DaveReid]

Hi David, I only lose lat/long from the aircraft in Myflights.  When you scroll across to the end of the aircraft, everything is there except lat/long.

OK - but does the track and GS still change after you lose the lat/lon, or are they stuck at the last received values?

If it's only lat/lon and not track/GS that stops being updated, then I would strongly suspect an encoding/decoding bug. 

There is no reason that I can see for 112-bit Airborne Position squitters being lost while 112-bit Airborne Velocity squitters are still being received.

[Mike_Tassy]

Hi David, yes track alt and GS still populate, its only lat/long that is lost.
I have takenmy ANRB out of line for a bit , am using my SBS-1e for a while. Will put it back on line later
Mike

[Mike_Tassy]

"Can you capture some port 30003 output? Telnet should do it, then you can paste a bit here and no doubt Dave Reid can pronounce."

Ok will get onto it
Cheers bed time for me
Mike

[Jeremy]

I still wonder if I have a 'null area' which I have discussed before. If you look at the attached screen shot you can see MyFlights to the West and around London approaching Heathrow. The network is seeing the a/c on the ground at Heathrow but there are only 2 a/c in the straight line approach from the east. Even though the timeout is only 10 secs from live to realtime, there seems to be a period where direct signal is the same value as what the network is sending, so nothing gets displayed.  The network coverage around London should should show more. Just a theory.
J.

[DaveReid]

there seems to be a period where direct signal is the same value as what the network is sending, so nothing gets displayed.  The network coverage around London should should show more. Just a theory.

Easily tested, of course, by turning the network off and seeing if the problems persists.

[tarbat]

I still wonder if I have a 'null area' which I have discussed before.

One way to check is to run OverFlightLogger.  WIll give you a complete coverage map by flight level - here's mine as an example - http://www.tarbat.gofreeserve.com/polar.htm

[AirNav Support]

there seems to be a period where direct signal is the same value as what the network is sending, so nothing gets displayed.  The network coverage around London should should show more. Just a theory.

Easily tested, of course, by turning the network off and seeing if the problems persists.

The network value would only be "fresh" for that one second after its downloaded. After which any other message you get from your box will be used.

[Jeremy]

Well there is a revelation.
Airnav - Please look at the 2 screen shots.
They are less than 1 minute apart the second having unchecked 'Process Hardware Flights.
Up pop a load of a/c on the Heathrow flight path.
Any comments gratefully received.
J.

[AirNav Support]

Jeremy,

Where is your home location on that map? If you don't want broadcast it PM us, as it seems you are getting network flights for low altitude flights which means you don't have them in line of sight fully.

The issue your showing is nothing to do with the issues mentioned from people in New Zealand and Australia. In your case Jeremy you may be getting a weak signal from those aircraft but only Mode-S, these messages are then blocking out the network aircraft as your receiving from them locally.

We can fine tune the settings of aircraft going from local to network flights but it’s sometimes not an easy item as some aircraft might go back and forth out of range.