Stratus Disappointment

[GaryP1007]

This is an excerpt from a friend's letter to ForeFlight......

 

 

I've been using, (and learning about), Foreflight with a Stratus 1 receiver for a few months now.  The flight planning and GPS features, including the positioning on IFR plates and taxi diagrams, are great.  I remain, however, confused and disappointed with the weather and traffic features.  I've already contacted you concerning the traffic feature.  Although I didn't subscribe to Foreflight to get traffic, (most of my flights are IFR), it has recently been advertised that with the latest software and firmware downloads, some traffic would be displayed.  Since the required downloads, I've flown on four flights in and out of a busy class B airport and have yet to see a single traffic blip!  

 

I did, however, subscribe to get the weather product.  Two days ago I was in IMC with precip in the area for the first time since using Foreflight/Stratus.  I was very disappointed at the pixelated (block-type) display, and totally shocked by not being able to animate the cells.  Rereading the Stratus description on Shorty's web site and the  comparison between ADS-B and XM weather on yours, I was aware that there would be a slight difference in resolution (the difference is huge!) but can't find the lack of animation while in the air documented anywhere.  This, to me, is a major over site AND a potential safety issue.  Consider this please: I sat in my home during a rainy evening, getting used to my new software, and was totally impressed with the quality of the weather that was being displayed on my mini ipad AND the smooth animation ability.  I was connected, of course to my home's Wi-Fi.  I had no clue that while in the air I would get a completely different depiction of the weather and NOT be able to animate it.  My real world situation the other day had a red square a few miles from my home airport that not only didn't move for a twenty minutes; I was UNABLE to to find the "play" button to animate it. 

 

In an effort to understand this new technology better, is this a weakness in the Foreflight software or the Stratus hardware?  If my lack of traffic and disappointing weather displays are not typical, could I be having trouble with my Stratus unit?  Lastly, if this level of weather service is all that is being offered to date, what is the time frame for introducing improvements to raise your product to the level XM weather? (I cancelled my XM subscription based on the advertised descriptions of both Foreflight and Stratus but will have to subscribe again if this is all I can expect from Foreflight/Stratus)

 

[Marauder]

Gary -- I think people are having a hard time understanding the limitations of this technology. Doing a fixed motion map of Wx while on a WiFi based data feed is a lot different that doing a moving motion map depiction of that same information in flight uploading from low bandwidth ASDB transmissions. As well, I would have expected better traffic from what is described in the letter, but keep in mind that he needs to pick up the traffic from the environment if he doesn't have ADSB out capabilities. Last year ForeFlight spoke about why they were not offering traffic at that time. It had a lot to do what people could realistically expect to see.

[GaryP1007]

Gary -- I think people are having a hard time understanding the limitations of this technology. Doing a fixed motion map of Wx while on a WiFi based data feed is a lot different that doing a moving motion map depiction of that same information in flight uploading from low bandwidth ASDB transmissions. As well, I would have expected better traffic from what is described in the letter, but keep in mind that he needs to pick up the traffic from the environment if he doesn't have ADSB out capabilities. Last year ForeFlight spoke about why they were not offering traffic at that time. It had a lot to do what people could realistically expect to see.

Understood re: traffic.....however he is picking up ZERO traffic even when going into Boston Logan.  I am a huge ForeFlight supporter, but the weather will have to be the same of better when compared to XM in order for people to stay excited.

[jlunseth]

Well, or is it an issue with the Stratus 1 rather than the 2, which is later technology and probably has more bandwidth to deal with traffic and weather displays.

[Marauder]

Well, or is it an issue with the Stratus 1 rather than the 2, which is later technology and probably has more bandwidth to deal with traffic and weather displays.

You may be onto something. I think the Stratus 1 firmware update came after Stratus 2 came out. Wonder if there is a glitch in that update. From the graphical representation I have seen, the differences betwen composite and context display of weather (XM versus ADSB) was enough that some people felt things were missing.

[201er]

I have the Clarity SV, and it works great. I don't have the ADSB out but I get all the targets in the NY Class B airspace out of which I operate. In this busy airspace someone is bound to have out and this is where I need the traffic info the most. I intentionally chose a dual band receiver to double the chances of picking up someone else's traffic response.

[Bennett]

Since I have retained my XM subscription, displayed my my Garmin 796, and I have a Garmin GDL88 ADS-B IN/OUT installation displaying on my GTN750 and GTN650 I have had the opportunity to compare the weather displays.  In my opinion XM weather is far superior in flight to ADS-B NexGen weather, and worth the subscription cost. NexGen is not worthless, just not a good as XM's presentation, especially for winds aloft, and other XM extensions beyond just the basic weather display. NexGen, at least in my experience is "blocky" in comparison with XM.  But the traffic display is where ADS-B IN/OUT really shines.  As mentioned in earlier posts I am seeing more traffic on the GTN650 and GTN750 screens than I have ever seen with "eyeballs" alone. Actually awesome, and has been of great value in avoiding potential midairs. 

[Greg_D]

It looks like folks are unaware of the limitations of ADS-B weather and traffic.  Limited traffic, while received in the original Stratus was filtered out for precisely the reason the OP's letter mentioned.  With a firmare update, traffic is visible with the Stratus 1.  That said, very little (<5%) of traffic is going to be displayed as things sit right now.  In order to see ADS-B traffic on ANY device, something has to "wake up" the ADS-B ground station in your local area.  If you don't have ADS-B out in your plane, another aircraft that's nearby will have to do this.  The fact is, there aren't many ADS-B out equipped aircraft these days.  Therefore, nothing wakes the ground station to transmit the trafic data.  The limitations have nothing to do with available bandwidth between the Stratus 1 and 2 models.

[laytonl]

I have been flying with both XM and ADSB weather for a few months and XM weather is definitely better, but I'm comfortable enough with the ADSB weather to drop the $35 per month XM cost. I also have a Stormscope, which I believe is needed to get a good view of the weather in the Southeast.

Lee

[Piloto]

I dropped my XM\WX subscription due to the relative little use for it even though I fly in Florida. I found that most of the weather info I  wanted to have it before flight. I can easily get the same XM\WX weather info (and more) from the NOAA website on my Samsung S3 from the ground up to 6,000feet and on occassions to 9,000feet. I prefer to know about the TFRs before leaving to the airport rather than after takeoff. I also have Stormscope onboard that works pretty well for me, specially in the Caribbean. There is no XM\WX or ADS-B WX coverage in the Caribbean. But cell phone coverage is pretty good for getting weather onboard. Many of the islands have cell phone towers on mountain tops that helps on the coverage.

 

José  

[bnicolette]

There is no question that the radar displays using ADS/B is not nearly as "smooth" as on XM but it still works just fine.  I have run ADS/B right beside the XM and other than the ADS/B being "blocky" it is right on with what it's displaying.  For me, it's a no brainer to go with the ADS/B in my little airplane.  It's free.

 

This picture was actually taken on the ground picking up ADS/B.  I flew 7 legs in the last two days and used nothing but the ADS/B on Foreflight and found it to be outstanding and there was a fair amount of weather around.  Of course I had onboard radar though.  The Stratus unit had no problems picking up all the information at FL300 moving at  M.80

 

http://flightaware.com/live/flight/N211RN/history/20130510/1900Z/KAFJ/KTEB

 

 

We also did this route using nothing but Foreflight and ADS/B

 

http://flightaware.com/live/flight/N1162G

[jnisley]

I have an Angel Flight scheduled for Tuesday (KGKJ-KLOZ-KOSU-KGKJ), I'm planning on putting my Stratus 2 to the test for the first time along side my trusty GDL 69/XM weather/MX20, the KGKJ-KLOZ leg will take me through an area that doesn't have good ADS-B coverage according to their map so we'll see what happens.

[aviatoreb]

There is no question that the radar displays using ADS/B is not nearly as "smooth" as on XM but it still works just fine.  I have run ADS/B right beside the XM and other than the ADS/B being "blocky" it is right on with what it's displaying.  For me, it's a no brainer to go with the ADS/B in my little airplane.  It's free.

 

This picture was actually taken on the ground picking up ADS/B.  I flew 7 legs in the last two days and used nothing but the ADS/B on Foreflight and found it to be outstanding and there was a fair amount of weather around.  Of course I had onboard radar though.  The Stratus unit had no problems picking up all the information at FL300 moving at  M.80

 

http://flightaware.com/live/flight/N211RN/history/20130510/1900Z/KAFJ/KTEB

 

 

We also did this route using nothing but Foreflight and ADS/B

 

http://flightaware.com/live/flight/N1162G

 

509KTS.  That must be a Mooney Acclaim.  Nice jet.

[aviatoreb]

I am very curious to hear from you folks adopting the stratus 2 about the traffic.  It seems that the weather is clearly up to snuff.

 

I would think that the traffic would work well just when you need it most - in the B and C terminals since don't most/all of the airliners have adsb out to trigger the system?  I used to have an airplane with mode s and I received traffic in all these spaces about all the time for this reason.  So I would think something is wrong if the stratus 1 is not showing any traffic in a busy class B.

[Piloto]

Gary 

 

I think it is unfair to compare ADS-B WX with XM\WX. XM\WX is broadcasted on a clear channel from a single point in space with no interference issues. The fact that you can receive XM\WX signal inside a hangar anywhere in the US gives you an idea of the quality of the broadcast. While ADS-B UAT broadcasts are subject to interference from multiple sources. UAT broadcast are on the same band as DME and Transponder. 200W from your transponder or DME can cause data corruption in addition to other ADS-B planes broadcasting their position on the same UAT channel (978MHz). Next time you go up try turning off the DME and transponder to see if there is any improvement.

 

José 

[OR75]

Gary 

 

I think it is unfair to compare ADS-B WX with XM\WX. XM\WX is broadcasted on a clear channel from a single point in space with no interference issues. The fact that you can receive XM\WX signal inside a hangar anywhere in the US gives you an idea of the quality of the broadcast. While ADS-B UAT broadcasts are subject to interference from multiple sources. UAT broadcast are on the same band as DME and Transponder. 200W from your transponder or DME can cause data corruption in addition to other ADS-B planes broadcasting their position on the same UAT channel (978MHz). Next time you go up try turning off the DME and transponder to see if there is any improvement.

 

José

piloto

i really don't know but i sincerely and respectfully hope you are wrong.

if ads-b is subject to interference, i am really worried as this is the base of ATC future!

[jetdriven]

I have DME a transponder, and a GDL-39. I cant remember ever not getting data above 500 AGL in about 100 hours now.

[bnicolette]

Some more pics of ADS/B in action.  Also have 2 DME's in this airplane and no problems with receiving multiple stations even up in the flight levels with no external antenna, heated windshield and the Stratus 1 just thrown up on the glare shield.

[Piloto]

piloto

i really don't know but i sincerely and respectfully hope you are wrong.

if ads-b is subject to interference, i am really worried as this is the base of ATC future!

You can read more about DME interference on UAT at:

 

http://adsb.tc.faa.gov/WG5_Meetings/Meeting6/UAT-WP-6-12.pdf

http://adsb.tc.faa.gov/WG5_Meetings/Meeting3/UAT-WP-3-10.pdf

 

The issue is not new

 

The same happens with the onboard transponder and TCAS. Onboard transponder, TCAS and DME equipment transmit wide spectral pulses that can easily interfere with UAT reception even when not in the same frequency. To overcome corrupted data a comon suppresion line connects all the equipment. With TCAS, DME, and TXPR data corruption is minimal due to the very short messages nature and high PRF. But UAT WX broadcast messages are much longer thus more subject to corruption. Depending on the receiver design this can cause missing pieces of weather data or weather data delays.

 

José 

[bnicolette]

I have an Angel Flight scheduled for Tuesday (KGKJ-KLOZ-KOSU-KGKJ), I'm planning on putting my Stratus 2 to the test for the first time along side my trusty GDL 69/XM weather/MX20, the KGKJ-KLOZ leg will take me through an area that doesn't have good ADS-B coverage according to their map so we'll see what happens.

 

There in lies the real downfall of the ADS-B system currently.............the lack of coverage in certain areas.

 

 

The same happens with the onboard transponder and TCAS. Onboard transponder, TCAS and DME equipment transmit wide spectral pulses that can easily interfere with UAT reception even when not in the same frequency. 

 

I haven't noticed anything as far as interference goes and have everyone of these sub systems onboard.  Not to say that it can't happen but I've had seamless information since I've been using the Stratus 1 and like Jetdriven probably have close to 100 hours of use on it.  I am also located near Pittsburgh, PA and most of my flying takes place up and down the east coast so there are no voids in coverage here either.

 

I'm wondering that if you were going to have interference issues if they would be apparent all the time or just occasionally?  So if I haven't noticed any in my airplane, is it likely that I never will?

[Piloto]

There in lies the real downfall of the ADS-B system currently.............the lack of coverage in certain areas.

 

 

I haven't noticed anything as far as interference goes and have everyone of these sub systems onboard.  Not to say that it can't happen but I've had seamless information since I've been using the Stratus 1 and like Jetdriven probably have close to 100 hours of use on it.  I am also located near Pittsburgh, PA and most of my flying takes place up and down the east coast so there are no voids in coverage here either.

 

I'm wondering that if you were going to have interference issues if they would be apparent all the time or just occasionally?  So if I haven't noticed any in my airplane, is it likely that I never will?

Interference susceptibility is primarily a function of distance from the UAT station. The farther you are from a UAT station the weaker the signal thus more prone to be jammed by onboard equipment. It is also a function of the DME channel selected and operating mode (search/track). More at: http://leagueofextraordinarytechnicians.wikispaces.com/DIstance+Measuring+Equipment++-+Operation

 

You may have not experienced data problems because you may be in a good coverage area. But in the event of having UAT reception problems try turning off the DME and maybe the transponder.

 

José 

[FlyDave]

I'm curious as to the success and image quality using a GDL-39 and Garmin Pilot. Is anyone using that combination? Can you post images of it?

 

Thanks,

 

Dave

[Jeff_S]

I ran the firmware update for my Stratus 1 and flew with it last weekend, all around the metro Atlanta area which has good ADS-B coverage. I was especially keen to see how the traffic would work, knowing that since I don't have ADS-B out in my plane it would be hit or miss.

 

One one leg, I saw absolutely no traffic anywhere on the device. But on another leg, as I was returning to the city, I saw about a half-dozen traffic hits, including one that also corresponded fairly well with my PCAS device. So clearly, on the second leg someone else in my vicinity had ADS-B Out and I was benefiting from that.

 

Either way, even if I had ADS-B Out in my plane, I can't see using the ForeFlight/Stratus traffic information unless I had the iPad mounted somewhere and part of my regular scan. Since that isn't going to happen, I see traffic as a novelty item at best. 

[Piloto]

Either way, even if I had ADS-B Out in my plane, I can't see using the ForeFlight/Stratus traffic information unless I had the iPad mounted somewhere and part of my regular scan. Since that isn't going to happen, I see traffic as a novelty item at best. 

 

To be effective you need to have "traffic" voice annunciation. Otherwise you will need to be looking at the ForeFlight screen constanly. Pop-up traffic such as that departing from an airport may show within 1nm from you without prior indication. This is where the voice warning really helps. Pop-up traffic is common on TIS-B and UAT reported traffic. This is because the traffic needs to reach a minimum altitude to be visible by the ATC radar.

 

José 

[jetdriven]

We have that with the GDL-39 and Aera. Its tied into the audio panel.  Terrain alerts too.