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AirNav RadarBox and RadarBox24.com => AirNav RadarBox and RadarBox24.com Discussion => Topic started by: FL350 on October 04, 2011, 11:52:57 PM

Title: Hardware Error?
Post by: FL350 on October 04, 2011, 11:52:57 PM
Greetings to all,

V3.13 / Windows 7...

I'm experiencing a new problem with my radarbox. I usually filter for ADS-B only aircraft, and my timeout is set to 30 seconds for hardware flights.

In the last few days, the number of hardware flights returned has been fluctuating by multiples of 10 or more (from say, 60 to 50) all at once without any timeout at all. This has never happened before, and the flights should time out for 30 seconds before disappearing off the screen. In fact, I'm not seeing any flights time out - They simply disappear from the screen.

I've cycled power on all hardware and checked all connections to the USB cable (edit: I've also switched to an Windows XP Pro machine and reproduced the problem)

Any input or experience with this issue?

Thanks to all!
Title: Re: Hardware Error?
Post by: AirNav Support on October 05, 2011, 07:40:57 AM
Hi FL350,

If you don't filter only by the ADS-B aircraft do you see the time-outs in the list, is there also such variation?

The reason why we ask this, is that some aircraft will show as ADS-B and the as they leave your reception area you won't be getting the longer positions messages from them and they will only show in the full list then appear to time-out when all signals are lost.
Title: Re: Hardware Error?
Post by: FL350 on October 05, 2011, 02:42:42 PM
Thanks AirNav for the quick reply,

Yes, if I don't filter Hardware Flights I do return a handful of Timeout flights.

However, I no longer see any Timeouts for filtered flights (ADS-B Only) at all. Regardless of filtering, they are dropping in and out (without timeouts) in areas well inside my polar diagram range. In general, I'm also seeing fewer returns during peak times.

So, if I am seeing multiple ADS-B flights (well within my reception range) drop in and out of reception without turning grey on the map I can only assume the hardware or software was somehow affected.

If I loose 10 flights at once, I should see 10 grey returns on the screen (and 10 Timeouts on the list) for time specified to display them. Instead, my screen now glimmers with returns completely dropping off and then returning within a few seconds.

Many thanks for your help, and I hope I've explained this well! Please let me know if I can elaborate on anything.

FL350
Title: Re: Hardware Error?
Post by: FL350 on October 06, 2011, 08:31:28 PM
From what I have described in my reply, does this sound like a hardware issue?

1) I am returning much fewer hardware flights
2) Hardware ADS-B flight returns fluctuate by as much as 10 to 15 all at once, without timing out on the screen or list
3) What used to be solid trail lines (within strong reception areas) now look very punctuated due to frequency of flights dropping in and out
4) If flights are lost they should first turn to Timeout colour and remain for specified Timout for MyFlights. This is what they did until a few days ago.
Is this possibly a negative effect of upgrading to live network traffic? Please advise if I should consider returning the box for examination.

Thanks
Title: Re: Hardware Error?
Post by: AirNav Support on October 06, 2011, 08:57:27 PM
We would suggest trying to take the box to another location. It could be local interference which is causing such large fluctuations. If its still same contact support and we will give you return details.
Title: Re: Hardware Error?
Post by: tarbat on October 07, 2011, 09:00:41 AM
Is this possibly a negative effect of upgrading to live network traffic?

Possibly.  My understanding is that aircraft that timeout on the hardware will immediately transition to the Network list if that aircraft is on the live network.  Try turning OFF the live network (untick the "Get Flights from Radarbox Network" box), and see what happens.

Also, check your timeout settings for MyFlights and Network Flights.
Title: Re: Hardware Error?
Post by: FL350 on October 16, 2011, 12:40:40 AM
Is this possibly a negative effect of upgrading to live network traffic?

Possibly.  My understanding is that aircraft that timeout on the hardware will immediately transition to the Network list if that aircraft is on the live network.  Try turning OFF the live network (untick the "Get Flights from Radarbox Network" box), and see what happens.

Also, check your timeout settings for MyFlights and Network Flights.

Thanks Tarbat,

Actually, that part of the functionality does indeed work properly. Flights on the edge of my range immediately show the network asterisk when I loose them. My timeout setting is 30 seconds and that's what they used to do.

I'm guessing that the issue (while it's intermittent) isn't going to go away, but am checking everything else before I send the box back.
Title: Re: Hardware Error?
Post by: Northern Watch on October 16, 2011, 07:19:03 PM
Hi FL340

This is a bit of a long shot but have you changed the USB lead, known problem with some users in the past although this particular problem is a new one on me.

Just a thought!

Hope you get it fixed soon.

Rgds

Keith
Title: Re: Hardware Error?
Post by: FL350 on October 16, 2011, 09:33:07 PM
Hi FL340

This is a bit of a long shot but have you changed the USB lead, known problem with some users in the past although this particular problem is a new one on me.

Just a thought!

Hope you get it fixed soon.

Rgds

Keith

Hi Keith,

Yes, I did switch it out in the beginning and I had hoped that was the root cause, but no luck.

Airnav, while I think of it, there are no electrical sources near the box (within 3m or so) I did try and move it but no luck there, either.

This issue is clearly intermittent. If it were the aerial, I would of course simply have less returns, shorter range, etc.

When the box is operating properly I have many more returns, solid trails and consistent returns that fluctuate gradually by one or two at a time. Still no timeout flights, but no great fluctuations, either.

When it acts up, the returns I do receive fluctuate immediately by a factor of 5, 10 or more, and the screen looks like a christmas tree. The trails are never solid in this case.

I'd be happy to upload a screen video to demonstrate this if need be.

I hate to be down, and can only guess that I have an audience when I'm running. I return tons of activity right down to the tarmac at KJFK (and happily share, of course).

Thanks!





Title: Re: Hardware Error?
Post by: AirNav Support on October 17, 2011, 07:48:31 AM
The hardware has no moving parts so it does seem strange that sometimes it starts playing up, if there is an issue it should affect it always. I would suggest checking a few items first such as when the variations occur check your task manager and check whether the memory or cpu is spiking.

Also close down the software and start it again and see whether the issues go away. Also note the time when it happens.
Title: Re: Hardware Error?
Post by: tarbat on October 17, 2011, 11:19:31 AM
Also check for anything that might be turning on around the house that is causing interference.  I believe others have reported problems in the past with certain types of lighting, for example.

EG: http://www.airnavsystems.com/forum/index.php?topic=2743.msg24597#msg24597
Title: Re: Hardware Error?
Post by: FL350 on November 15, 2011, 08:32:33 PM
The hardware has no moving parts so it does seem strange that sometimes it starts playing up, if there is an issue it should affect it always. I would suggest checking a few items first such as when the variations occur check your task manager and check whether the memory or cpu is spiking.

Also close down the software and start it again and see whether the issues go away. Also note the time when it happens.

Thanks Airnav for you help thus far.

I have 4GB RAM in which at least 2 is free during typical operation with the software. The CPU isn't over tasked, either. Perhaps 20 per cent max.

I fully understand the box is completely solid state. To that end, I have read that it has been susceptible to ESD in the past. Purely speculation on my part, but it this did happen to be the cause, ESD can most certainly cause intermittent failures in operation.

I do have another question:

Is there a limit to the amount of ADS-B and Mode S data the RadarBox can handle? I have a well-tuned vertical aerial which is mounted about 12m off the ground. The cable to the box is very low loss (about 7m) so I don't require a pre-amp.

What I have noticed since my last post is that the most annoying part of the problem is occurring during heavy traffic periods. I typically return 500 - 800 (and above) messages per second during these times.

During light traffic times the flights don't 'flicker' on and off the screen, the trails are quite solid behind the aircraft, indicating a steady processing of the incoming data. The 'MyFlights' count never jumps by more than 1 or 2 during this time. I still never see 'My Flights' Time Out at all anymore, but this is much less bothersome to me.

Please reference the 4 attachments demonstrating both cases. Two show affected operation and two show normal operation. Also note the time periods for the pairs of screenshots. Also take notice that flights are affected well within my polar diagram, which is more or less the maximum reported range.

I appreciate your help and want to make sure I've addressed all possible causes on my end before sending the box back. I don't want to be without the box if I can fix it myself, and certainly don't want to waste your time, either!

Regards,

FL350

Title: Re: Hardware Error?
Post by: FL350 on November 15, 2011, 08:40:00 PM
Also check for anything that might be turning on around the house that is causing interference.  I believe others have reported problems in the past with certain types of lighting, for example.

EG: http://www.airnavsystems.com/forum/index.php?topic=2743.msg24597#msg24597

Hi Tarbat,

I did wonder about that as well, but no changes have occurred in what's turned on in the house. There's nothing electrical (either lines or appliances) close to the box.

Cheers,

FL350
Title: Re: Hardware Error?
Post by: tarbat on November 15, 2011, 09:33:52 PM
I have 4GB RAM in which at least 2 is free during typical operation with the software. The CPU isn't over tasked, either. Perhaps 20 per cent max.

Is that 20% of a single CPU core, or across all cores?  For example, if it's a quad core CPU, then 25% would be max'ing out a single core.

What I have noticed since my last post is that the most annoying part of the problem is occurring during heavy traffic periods. I typically return 500 - 800 (and above) messages per second during these times.

I guess you might be getting data collisions with high message volumes - ie. messages being received at the same time interfering with each other.  Maybe others in high traffic areas can comment.

I still never see 'My Flights' Time Out at all anymore, but this is much less bothersome to me.

Is that with the network on or off?  And what exactly are your timeout settings - the two values for local flights?  For example, I use 13 seconds and 107 seconds, so aircraft get marked as TIMEOUT after 13 seconds, and dissapear after another 107 seconds - so appear with TIMEOUT status for 107 seconds.
Title: Re: Hardware Error?
Post by: FL350 on November 15, 2011, 09:52:10 PM
What I have noticed since my last post is that the most annoying part of the problem is occurring during heavy traffic periods. I typically return 500 - 800 (and above) messages per second during these times.

I guess you might be getting data collisions with high message volumes - ie. messages being received at the same time interfering with each other.  Maybe others in high traffic areas can comment.

I still never see 'My Flights' Time Out at all anymore, but this is much less bothersome to me.

Is that with the network on or off?  And what exactly are your timeout settings - the two values for local flights?  For example, I use 13 seconds and 107 seconds, so aircraft get marked as TIMEOUT after 13 seconds, and dissapear after another 107 seconds.

I've attempted to change the values to a number of ranges, but it really makes no difference. Currently I'm set to 20/30 for radarbox flights. No map (greyed out) or status timeouts at all for ADS-B flights regardless of settings.

In any case, it seems repeatable to see more stable returns during slow hours (not a very large window of opportunity around here).
Title: Re: Hardware Error?
Post by: tarbat on November 15, 2011, 09:56:35 PM
In any case, it seems repeatable to see more stable returns during slow hours (not a very large window of opportunity around here).

I guess you could test with the standard antenna rather than your DPD to simulate a reduced volume of messages in order to help diagnore the cause of the problem.

Also test with network OFF and no filters (such as ADS/B only) applied.
Title: Re: Hardware Error?
Post by: FL350 on November 15, 2011, 10:07:53 PM
I have 4GB RAM in which at least 2 is free during typical operation with the software. The CPU isn't over tasked, either. Perhaps 20 per cent max.

Is that 20% of a single CPU core, or across all cores?  For example, if it's a quad core CPU, then 25% would be max'ing out a single core.

What I have noticed since my last post is that the most annoying part of the problem is occurring during heavy traffic periods. I typically return 500 - 800 (and above) messages per second during these times.

I guess you might be getting data collisions with high message volumes - ie. messages being received at the same time interfering with each other.  Maybe others in high traffic areas can comment.

I still never see 'My Flights' Time Out at all anymore, but this is much less bothersome to me.

Is that with the network on or off?  And what exactly are your timeout settings - the two values for local flights?  For example, I use 13 seconds and 107 seconds, so aircraft get marked as TIMEOUT after 13 seconds, and dissapear after another 107 seconds - so appear with TIMEOUT status for 107 seconds.

That's about 25% of a single core. 2 cores are typically 'parked', btw., and this behaviour occurs regardless of network being on or off.
Title: Re: Hardware Error?
Post by: FL350 on November 15, 2011, 10:16:07 PM
In any case, it seems repeatable to see more stable returns during slow hours (not a very large window of opportunity around here).

I guess you could test with the standard antenna rather than your DPD to simulate a reduced volume of messages in order to help diagnore the cause of the problem.

Also test with network OFF and no filters (such as ADS/B only) applied.

I have checked it with the stock antenna before and seem to remember it didn't act up as much. It certainly wouldn't hurt  to try again (and with filters/network off as you suggest).

In fact, I'll try both, then each suggestion independently. I'm not sure that I've turned off the filter and network simultaneously.

If you happen to be watching the network now, you'll notice the ground returns disappear from JFK. Kudos to the DPD! Also, my range was hugely expanded with this setup. What a nice aerial!!!

Cheers
Title: Re: Hardware Error?
Post by: tarbat on November 15, 2011, 10:24:00 PM
If you happen to be watching the network now, you'll notice the ground returns disappear from JFK. Kudos to the DPD! Also, my range was hugely expanded with this setup. What a nice aerial!!!

Sorry, I don't have a network subscription anymore :(  Yes, the DPD is a great antenna, but I guess there is a chance that it's overloading your system with a large message volume.  Non-ADS/B messages are a lot shorter than ADS/B messages, so could be colliding with ADS/B messages that then get lost/corrupted.  Maybe someone with a similar message volume can comment - I rarely get above 80 messages per second!!
Title: Re: Hardware Error?
Post by: FL350 on November 15, 2011, 10:32:48 PM
If you happen to be watching the network now, you'll notice the ground returns disappear from JFK. Kudos to the DPD! Also, my range was hugely expanded with this setup. What a nice aerial!!!

Sorry, I don't have a network subscription anymore :(  Yes, the DPD is a great antenna, but I guess there is a chance that it's overloading your system with a large message volume.  Non-ADS/B messages are a lot shorter than ADS/B messages, so could be colliding with ADS/B messages that then get lost/corrupted.  Maybe someone with a similar message volume can comment - I rarely get above 80 messages per second!!

I've just connected the stock aerial and am averaging about 250 / sec. I'll have to leave this connected for a while (of course at the expense of range and returns) and make some observations.

Judging by your locale you get more or less northernmost transoceanic flights, correct?
Title: Re: Hardware Error?
Post by: tarbat on November 15, 2011, 10:42:04 PM
Judging by your locale you get more or less northernmost transoceanic flights, correct?

Yes, a lot of transatlantic flights (ADS/B) and local ModeS civilian and military aircraft.  My main interest is military from the local airbases.

Good luck with the testing, and let us know how you get on.  It really doesn't sound like a hardware problem to me.  It may be that with a range of 200+ nm your receiving so many ModeS messages that the ADS/B messages get corrupted mid-transmission.
Title: Re: Hardware Error?
Post by: CoastGuardJon on November 15, 2011, 10:52:51 PM
Hi all, I don't thinks I've ever had solid trail lines, always broken/breaking up and bits disappearing as in :

Title: Re: Hardware Error?
Post by: FL350 on November 15, 2011, 11:00:15 PM

Good luck with the testing, and let us know how you get on.  It really doesn't sound like a hardware problem to me.  It may be that with a range of 200+ nm your receiving so many ModeS messages that the ADS/B messages get corrupted mid-transmission.

I'll let it run on both antennas for a few days and compare. I would consider this to be a serious limitation if it were simply the inability of the radarbox to handle that kind of data. It would seem countless others in congested areas of Europe would have encountered the same issue. Either way I eagerly await to hear from others with similar message returns.

Regards
Title: Re: Hardware Error?
Post by: FL350 on November 15, 2011, 11:03:12 PM
Hi all, I don't thinks I've ever had solid trail lines, always broken/breaking up and bits disappearing as in :



Hi CGJ,

It seems from the screenshot that you're displaying network data. Do you radarbox returns 'punctuate' in the same manner? I'll assume this is just a good example of your local returns (dotted)...
Title: Re: Hardware Error?
Post by: tarbat on November 15, 2011, 11:45:54 PM
Hi all, I don't thinks I've ever had solid trail lines, always broken/breaking up and bits disappearing as in :

Jon, we're discussing local hardware received aircraft, not network aircraft.  The trail lines will always be broken for network aircraft since you only receive position data every 20 or 30 seconds from the network.

I would consider this to be a serious limitation if it were simply the inability of the radarbox to handle that kind of data.

Of course I could be totally wrong about the explanation!!  Although I don't think its a limitation of the Radarbox, since if the Radarbox receives an ADS/B message that gets corrupted by a ModeS message transmitted at the same time, the checksum error checking must reject the ADS/B message.

I would imagine that as message rates increase then the chances of data collisions also increase.  At 800 msgs/sec, that's almost one message every millisecond, with an increasing chance of one message being corrupted by another.  And it's always more likely that the longer ADS/B message will get corrupted.

NASA have done some research (http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.118.6251&rep=rep1&type=pdf) on ADS/B message collisions, and came to this conclusion:
Quote
ADS-B performance trends were confirmed. Areas of increasing traffic density such as aircraft converging on a meter fix, showed higher probabilities for message collisions. With increasing traffic levels, overall reception probability decreased. When comparing to the industry standard LA Basin 2020 scenario for required traffic density to test ADS-B performance, the Joint Experiment had much fewer targets broadcasting ADS-B, especially nearer to LAX. Joint Experiment traffic levels do not follow the rapidly increasing trend close in to the airport because the significant impact of Mode A/C messaging over 1090Mhz from other vicinity airports and General Aviation traffic was not modeled.
Title: Re: Hardware Error?
Post by: FL350 on November 19, 2011, 03:05:12 AM
Many thanks Tarbat,

I've perused the NASA document and found it quite interesting. Perhaps the diminished returns I'm seeing are indeed typical of high traffic convergence limitations of the technology itself. Time will ultimately tell I suppose... I'd like to compare to other users in similar conditions.

I did connect the stock aerial and seemed to confirm that radarbox (or Mode S/ADS-B) is more stable with a weaker signal during heavy traffic. I've also confirmed that my radarbox (and assume others) will not show timeout flights at all when set to filter ADS-B only flights. They do show up for non-filtered flights for the most part, but occasionally drop off even in strong reception areas. That may be related to message collisions and/or an overloaded chipset as well.

FL350
Title: Re: Hardware Error?
Post by: tarbat on November 19, 2011, 08:58:05 AM
I've also confirmed that my radarbox (and assume others) will not show timeout flights at all when set to filter ADS-B only flights.

Remember that ADS-B equipped aircraft also transmit non-positional ModeS messages.  So, as an aircraft leaves your coverage area, the ADS-B messages may have stopped getting through intact, but the occasional non-ADS-B message (eg Altitude, FlightID, Squawk, etc.) will still be getting through intact.  Non-ADS-B messages are more likely to get through intact because they're shorter - 56µs against 112µs for ADS-B messages.

So, the aircraft hasn't timed-out, but you've stopped receiving ADS-B messages.  That's why the aircraft simply dissapears from your MyFlights list if it's filtered for ADS-B only.  They should still appear as timed-out flights (in grey) on the map.