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  #1  
Old 06-04-2018, 09:34 PM
MartySantic's Avatar
MartySantic MartySantic is offline
 
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Location: Davenport, IA
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Default uAvionix EchoUAT and Disappearing Targets

A few locally, and a few in Texas have experienced targets that disappear and sometimes reappear randomly. Anyone else experiencing the same? Anyone know if uAvionix is working on this issue?
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  #2  
Old 06-05-2018, 02:22 AM
Timberwolf Timberwolf is offline
 
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I've got the latest software and have seen the same on mine. It usually seems to happen with the traffic that's close by.
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  #3  
Old 06-05-2018, 04:55 AM
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maniago maniago is offline
 
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This is a known issue. It was discussed at length on the GNS480Yahoo group, and not that I fully understand the guts of the Echo, but the up shot as I believe is that the Echo does not filter or prioritize targets based on range or altitude. It just fires all it gets down the 232 pipe. When that pipe gets overloaded, it drops and re-acquires targets at random...........

I believe Uavionix argument for this implementation is to let the EFIS mfg do the prioritization and filtering - I cant explain how that works if stuff is getting dropped at the input cause that makes no sense to me - maybe someone better can explain it. In anycase, I talked to Jeff at GRT about it and they know about it and do some processing to handle the situation, but more work apparently needs to be done.

Again, if someone else can explain it better/knows more, like you guys, I'm all ears.....
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Mustang II (FoldingWing) "Firewall Fwd stage.Yea!" IO-360B1E,RSA,C2YR-BF/F7666-2,Superior sump,James; 2xHXr,MiniX,EIS,480,327,240,SL30,(maybe)Echo; SteamAlt,AS,VSI
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Last edited by maniago : 06-05-2018 at 05:00 AM.
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  #4  
Old 06-05-2018, 05:59 AM
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rleffler rleffler is online now
 
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Quote:
Originally Posted by maniago View Post
This is a known issue. It was discussed at length on the GNS480Yahoo group, and not that I fully understand the guts of the Echo, but the up shot as I believe is that the Echo does not filter or prioritize targets based on range or altitude. It just fires all it gets down the 232 pipe. When that pipe gets overloaded, it drops and re-acquires targets at random...........

I believe Uavionix argument for this implementation is to let the EFIS mfg do the prioritization and filtering - I cant explain how that works if stuff is getting dropped at the input cause that makes no sense to me - maybe someone better can explain it. In anycase, I talked to Jeff at GRT about it and they know about it and do some processing to handle the situation, but more work apparently needs to be done.

Again, if someone else can explain it better/knows more, like you guys, I'm all ears.....
There is also another known issue with some of the other UAvionics receivers in metro areas where you may have line of sight to multiple adsb towers. The quick fix was to use the Flightaware ADSB filter in series in the antenna input.

When I was testing the new Dynon unit, this greatly improved the reliability of the 472, until Dynon had uAvionic add the filters into the final production unit.

While I have no specific knowledge, it may help with the other uAvionics units too. Its about $15, so it doesn't cost a whole lot to experiment a bit.
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  #5  
Old 06-05-2018, 02:48 PM
TimO TimO is offline
 
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I had horrible experiences all the way around with the Echo, but fixed most of the issues by building a GDL90 filter/converter box that also allows transponder and altitude encoder input for the Echo. There will be more information on it that I'll be posting towards the end of June and it's potentially something that I'll open-source out so that others can have the fixes too. Without it, the Echo is not a system I'd be happy with. Some of the issues are fixed behind the scenes by AFS/GRT/Dynon, for users of their systems, but most do not address the root cause...bad software on the Echo.

Anyway, more to come later. PM me if you want me to email you later, and shoot me your email address. Or email me if you wish. I'll be doing an extensive test flight in less than 2 weeks that'll cover a few thousand miles with 2 planes, and once that is done, I may share the project.
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  #6  
Old 06-06-2018, 06:22 AM
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maniago maniago is offline
 
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Default Triple play!

Kinda funny, I think theres 3 Echo threads active right now....

http://www.vansairforce.com/communit...d.php?t=160755
http://www.vansairforce.com/communit...d.php?t=161049

Too bad we cant merge them cause its all good info....tho I suppose it does show some angst over the product....lol

Too bad we cant get Uavionix to come up here and clear the air once and for all.
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Mani
Mustang II (FoldingWing) "Firewall Fwd stage.Yea!" IO-360B1E,RSA,C2YR-BF/F7666-2,Superior sump,James; 2xHXr,MiniX,EIS,480,327,240,SL30,(maybe)Echo; SteamAlt,AS,VSI
Don't be a hater; I'm a cousin with thin wings!
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  #7  
Old 06-06-2018, 09:01 AM
Bo1000 Bo1000 is offline
 
Join Date: Nov 2013
Location: Austin
Posts: 18
Default Hemispheric Altitude Rules?

My GRT EX lets me select the thickness of the airspace puck in which it shows traffic (traffic above and below the puck isn't displayed).

So, if I tell it to show traffic from 2000ft below to 2000ft above, and I fly at 4500ft, then traffic at 2500ft and 6500ft will blink on/off as my plane or the traffic bobbles around our respective hemispheric altitudes. I think this is all but guaranteed by the thickness selections in the GRT menu.

Seems like an easy fix would be for the GRT menu to allow setting a puck of arbitrary thickness (eg, 1750ft), or for the GRT display to add a little time hysteresis (keeps displaying the traffic for a while after it has moved out of the puck in case it moves back in).

Bo
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  #8  
Old 06-06-2018, 09:06 AM
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maniago maniago is offline
 
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Quote:
Originally Posted by Bo1000 View Post
.............to add a little time hysteresis (keeps displaying the traffic for a while after it has moved out of the puck in case it moves back in).

Bo

Jeff told me they do that, and I mention it in the other thread linked above where I posted his comments. In anycase, its called "coasting".....but how long the coasting window is, that I dont know...
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Mustang II (FoldingWing) "Firewall Fwd stage.Yea!" IO-360B1E,RSA,C2YR-BF/F7666-2,Superior sump,James; 2xHXr,MiniX,EIS,480,327,240,SL30,(maybe)Echo; SteamAlt,AS,VSI
Don't be a hater; I'm a cousin with thin wings!
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Dec2017
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  #9  
Old 06-06-2018, 11:32 AM
bhughes bhughes is offline
 
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Iím experiencing disappearing traffic also. In one instance I had visual on an army helo about 1000 ft. below at two miles and it the target would disappear and reappear every few seconds. It was not a puck size altitude issue. My old AFS EFIS wonít support ADSB so traffic display is limited to Foreflight. I sure miss my Navworx EXP. Iím considering firing the old Stratux back up and using it for traffic.
Bobby
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  #10  
Old 06-06-2018, 04:10 PM
TimO TimO is offline
 
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The blinking traffic is not from the traffic falling into and out of the puck around your aircraft, it's from that traffic not getting properly transmitted to your EFIS on the serial line. In my opinion, one of the huge flaws in the Echo is that it does not filter traffic at all to put on the RS232. We've done some work to calculate how many targets you can send via RS232, because in my case, the EFIS needed 38,400 baud. You really can't effectively run an EFIS sending it what may end up being 200 targets, at 38,400 baud. You can't even effectively send 200 targets at 115,200 baud. So if they don't filter them down to only the targets that you care about, the stock Echo will continuously overload the RS232 connection. They even break standards for what the GDL90 doc says, in that you're supposed to send all of the traffic in one message, but their message had to be broken into multiples in order to even send that many, so they send it in multiples. That means that, lets say your EFIS gets only 1 or 2 huge messages a second, you may not get the same traffic repeating in the timeframe that your EFIS wants to see it coming in. So it blinks. Miss more than maybe one or two sequences and you have blinking targets. It's just plain bad programming, which may be caused by hardware limitations...not sure.

What you WANT to do is first figure out what is REASONABLE to display. Maybe set an outer boundary of 50-100 miles that you simply ignore anything that's even out there. Closer, if you live in high traffic areas. Then, set a puck around the airplane vertically, so that you ignore all the airliners 20,000+ feet above you. Maybe set that puck to +/- 5000' vertically. So now that you're only looking at maybe 60 miles ahead and +/- 5000', you have a far lower count on traffic. You also increase SAFETY because, and people will poo poo and discount this, but EVERYTHING you display on the EFIS takes mental cycles to process. Add in traffic that is absolutely no factor, and it may cause you to have a higher workload just to mentally process it. Do that in an IFR environment and you are just asking for problems. Also, clutter the map page with too many targets and you may not be able to read map features or airport identifiers. So it's a safety thing.

So once you have that traffic pared down and you ignore all of that stuff you don't care about anyway, you sort it out by distance. That way you can focus first on sending out the traffic that is nearest your position. If you have 20 planes within 5 miles of you, like at OSH, WHY in the heck do you even CARE about the 150 planes that are 50 miles away? You don't. So sort them in a table, and track them. Maybe track 50 or so, just as a random number. A new one comes in that's closer than #50 and it bumps #50 off the list and re-sorts.

So now you have the nearest 50 targets, and you track them...speed, altitude, Vertical Speed, distance, closing rate, and such.

Now you pick a number that your EFIS can handle, without overwhelming the RS232 line. I'm sure if you ask GRT and AFS if they LIKE having a firehose of non-critical traffic coming at them, they would say they don't. But if you say you want to only display the nearest 20, you just peel off the top 20 on that list of 50 and transmit those via RS232.

Now the EFIS is happy. And, you can even coast them since you're tracking all of the targets parameters, so if someone is in a turn and their antenna doesn't transmit to you for 5 seconds, you don't blink them out...you calculate where they should be, so you still know which direction to look. Not too long, or you could have them significantly out in a different position...but maybe 5-10 seconds. As long as you calculate where they were headed and at what speed and vertical speed, you should be able to at least have a close approximation, which is better than having them there and not having any knowledge of them.

So that's a little preview of how this box that I've been working with another RV-10 guy on works. And, it works real well. I was ready to throw my Echo against a brick wall, but this makes it actually useful.

Sadly, I had one more big hurdle to overcome. The Echo doesn't have any sort of traffic collision algorithm that I can find. So, every target on my chelton EFIS would NEVER alert. I could literally aim my 2 planes at eachother (and I did) and fly at 150kts each right at eachother and then pass by eachother off our wing, and never get an alert. That was a function NavWorx DID offer, that uAvionix isn't as far as I can tell. NOT A HAPPY CAMPER after finding that out. But, thank goodness we had this project that I was working on. Thanks to a lot more programming, we added a bit of collision algorithm to it so that we can try to calculate if traffic is a factor or not, and alert well ahead of when we'll hit it. That was a lot of work to do just by general thinking it through. But, it works now.

There is more than that, but, suffice it to say that at least with my EFIS, I would never want to have that product in my plane, without being able to modify things a bit. Those of you who have GRT and AFS there to help overcome these issues are in a better situation for sure, but sadly, those companies are still going to suffer from the strangulation that the Echo puts on that RS232 line by trying to pass all that non-essential traffic. Were they (uAvionix) to do a bit more software development and product improvement, they could make the manufacturers (and users) much happier.

I have zero knowledge about their SkyBeacon and other products, such as their new transponders, so I can't really comment on those other than to say that I'm shocked enough by how many holes there are in the Echo that I will likely never look at those other products as an option. Once I pull this Echo out sometime down the road, I'm going with something like the Garmin 345 or Lynx NGT-9000. To me, traffic and especially weather, is far too important to skimp on.
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