Jump to content

ADSB vs XM weather


markmn

Recommended Posts

In the name of safety I would like to put a little personal experience out there.

 

I have a CFI the I regularly fly with. He has ADSB on his ipad with and when comparing the XM on the G3X it has not been nearly as detailed or accurate. I also noticed a comment in aviation consumer saying you can not look out farther than 250nm from your current location. Thats not very far if you going someplace. I dont know if it is true or not.

And of course we know there are some holes in ADSB coverage in less populated areas but should be filled soon.

 

Because I do a fair amount of VFR cross country flights I am going to keep my XM weather along with ADSB in the G3X and continue to do comparisons.

Based on my experiences so far I would not count on it for extended cross country flying.

 

Mark

Link to comment
Share on other sites

Reception was not the problem.

 

The actual depiction was not as clear or detailed and did not have the 'weather in motion" for trend analysis or cloud cover.

 

It was way better than nothing but not in the same league as nexrad.

 

Has anyone else used both and So I can be sure Im not missing anything here?

 

Mark

Link to comment
Share on other sites

My understanding is that you can look beyond 250nm, but that the weather depiction outside that range is low detail. You'll see major weather systems, but not really detailed information. This seems okay to me, since as you are moving you will constantly get 250nm of detail around you. That is plenty of time to make good decisions on diverting or changing your flight plan, and even the low-res long range weather will give you an idea of the trends.

 

Of course this doesn't address ADSB coverage gaps, and you might really want detailed weather for your whole route. But I don't think the ADSB scheme is "unsafe", and almost certainly it will get better over time.

Link to comment
Share on other sites

I would agree that when zoomed out it does not look bad. Its when you zoom in that you notice it is not as detailed.

 

If you regularly fly VFR near or around weather my experience says it will be wise to stick with Nexrad XM.

I see a number of people going the ADSB route and for the price why not?

I just want people to be aware ADSB weather is not Nexrad.

 

As far as Ipads I agree with gbigs. I would not depend on for navigation or weather. That said

many pilots do not have the luxury of dual EFISs and the I pad can bring awareness into the cockpit.

 

My ADSB and XM nexrad experience comes from having both in the aircraft at the same time and comparing.

If you had a different experience in direct comparison please let me know.

 

I am in no way poo pooing ADSB weather just saying it has less features and capability than nexrad and I want pilots to be aware of that.

 

Mark

Link to comment
Share on other sites

ADS-B radar resolution is less than XM but I wouldn't classify this as 'accuracy'. I also wouldn't bank on either of these sources being 100% accurate at the point in time you see them. They can be 15 minutes out-of-date so you shouldn't be using these to snake your way through a T-storm. Were the timestamps of the ADS-B weather and XM weather the same for your comparison? Timing plus resolution may explain the visual differences.

 

Also, don't worry about the 250nm 'regional' coverage as this is based (loosely) on your position so you'll always have the higher resolution product. Given we're flying at 1/2 this, it would take an hour (assuming you're in the middle) to reach the edge of your first regional image but by then you'd receive a feed from another ground station, thus creating a new region. Don't know how Foreflight works, but my 795 can interleave region and national radar, which gives you the best of both worlds.

Link to comment
Share on other sites

I have flown quite a few long cross country flights using Stratus/Foreflight and find it useful for planning and maybe route modification. If you want something that will help guide you thru cells, I would stay with xm.

 

After you learn the nuances between the 2 systems you will find that they give you basically the same info, at least that is what I have found.

 

Chris Marinello

N530CT

 

 

Link to comment
Share on other sites

Agree with S3 that the adsb accuracy is not less than nexrad just not as much information overall.

 

As far as the timing I cant say that I noticed one being updated quicker than the other but I dont think the ADSB was any slower than nexrad.

I will continue to compare and report if I learn anything new.

 

Because I fly cross country the "map in motion" feature is nice for anticipating the weather movement along with cloud coverage areas. Something I use regularly on XM.

 

Mark

Link to comment
Share on other sites

I have the integrated Dynon ADS-B box and have tried the weather a couple of times while out flying. On my last flight I zoomed out and storm activity over Michigan was shown while I was flying just north of Houston, so the 250 nm issue wasn't present.

 

I haven't checked to see if I get METARS from that far aways. I'm planning on flying this Friday. I'll pick an airport up north in the ADS-B coverage area and see if I can see a current METAR and TAF.

Link to comment
Share on other sites

Dan,

 

Did you have nexrad before using ADSB or?

 

Mark

 

Mark,

I didn't have anything before I got the Dynon ADS-B installed. I'm a low time new sport pilot, so I'm quite careful with the weather and my primary use of the ADS-B is for the enhanced traffic capability. The weather is also nice, but I use it mainly to check winds at airports.

 

But if I ever get "caught out" with a bad interpretation of a forecast or just a bad forecast then it will surely be useful.

Link to comment
Share on other sites

It all depends on your proximity to the ground station. For example:

  • I have coverage on the ground at my local airport in the DFW area with the closest station 18nm away
  • I have picked weather at 4-5000' MSL in areas that supposedly have no coverage
  • I received multiple station coverage at 1000' AGL with the closest station 50nm away

I do have a permanent installation with an external antenna which may be a factor.

Link to comment
Share on other sites

I went flying this past Friday and was able to zoom out to see radar for the entire continental US, but METAR's and TAF's were not available for the 2 airports I picked in Wisconsin. I selected them prior to takeoff.

 

Next trip I'll pick some airports around the 250 nm range to see about METAR's and TAF's. Probably will pick a range of distances starting at 50 nm.

 

I also have coverage on the ground, but I'm under the IAH airspace.

Link to comment
Share on other sites

  • 1 year later...

Skywalker, you'll need some form of ADS-B in solution for weather and spotty traffic.  If you want full traffic you have to go ADS-B in+out at considerable expense, probably $5k or more.

 

Since you have a Garmin 696, I'd probably suggest starting by looking at the Garmin GDL-39.  If you use an iPad with ForeFlight, Garmin Pilot, or WingX then which software you use will dictate the hardware to buy.  

Link to comment
Share on other sites

Skywalker are you asking because you want to get ADS-B "in" now so you can see weather and traffic or because you want to know how to be 2020 compliant for ADS-B "out".  The answer will differ depending on the question.

Link to comment
Share on other sites

I have the garmin 696 in my ctls along with the dual dynons .What do I need to do to-convert to the ads- b for weather and traffic.

If you have the Dynon transponder, then it it us simply adding their ADS-B in module ($ 1,000) to get full ADS-B until 2020.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...