ADS-B Not Receiving All AWOS Stations

[foxflyer2]

I just installed an ADS-B receiver in my Kitfox.  Everything is working great except I cannot receive metars for my home airport - 21D.  I get the message "Metars not available".  My question is whether anyone else has experienced this with their ADS-B receiver and an airport which have an alpha designation?  Is the problem with the FAA not transmitting the data from alpha designation airports (21D does have AWOS)?  Or is this a bug in the dynon software?  Any ideas?
Thanks!

 

[Garrett]

Get airborne the transmitter may be miles away. Also the FAA has not fully impemented the system yet. I believe the Eastern U.S. is mostly complete but not the West.

 

[foxflyer2]

My question was not stated very clearly.  I receive weather data from all airport is the MSP area with the exception of my home airport which has an alpha designation - 21D.  All the other airports have the conventional KXXX designations.

 

[dynonsupport]

You can't get 21D because it has no METAR.

ADS-B uplinks the same METARS and TAFs that you could get from FSS or on the internet. You can't get 21D because they don't report into the FAA's METAR system. It's a local broadcast only station. If you go to any internet site that looks up METARS and put in 21D it says there is none available. So it's not an ADS-B bug or a Dynon bug, it's just the way the FAA weather system works.

Here's a thread on why many AWOS systems don't make it into the FAA METAR system:

http://www.pilotsofamerica.com/forum/showthread.php?t=4288

 

[foxflyer2]

Hi Dynon Support:
Wrong! 21D does have a metar but it is listed under "K21D". Go to any internet site and put in K21D and it will display the metar. So again my question is why isn't K21D showing up an the ADS-B. Thanks.

 

[jlakins]

What I see is many state airports ( IE: 21D ) have metars but I think there is a disconnect between NWS and the FAA.
From NWS you access K21D but the official FAA registration for this airport is 21D.  If you search FAA for a K21D it will not find it.  If you search NWS for 21D it will not find it.
I notice the only weather reports showing up on my ADSB are ones prefaced with a K. My garmin 430W cannot find K21D but it will find 21D but for weather purposes it is K21D.

I think there are about 20,000 registered airports in the United States but only about 2,500 of them have official ICAO registrations.  Searching for METARS you must use the 4 letter ICAO format even if the airport is not registered in the ICAO database.

Dynon Support any comment?

 

[dynonsupport]

So it does appear we have a bug since we never knew that all METARS were preceded with a K. We thought they would always use the official FAA ident. Thus, we never associate the METAR K21D with the airport 21D.

We'll try and get this fixed in the next release so airports like 21D show up.

In looking at the data, this means we are leaving out about 300 METAR stations (out of 3,500). Interesting that nobody noticed in the last year we've had ADS-B!

 

[jlakins]

The following METAR field definition is from the AIM page 7-1-64.

ICAO Station Identifier.
The METAR code uses ICAO 4[ch8722]letter station identifiers.
In the contiguous 48 States, the 3[ch8722]letter domestic station identifier is prefixed with a “K;” i.e., the domestic identifier for Seattle is SEA while the ICAO identifier is KSEA.
Elsewhere, the first two letters of the ICAO identifier indicate what region of the world and country (or state)  he station is in.
For Alaska, all station identifiers start with “PA;” for Hawaii, all station identifiers start with “PH.”
Canadian station identifiers start with “CU,” “CW,” “CY,” and “CZ.”

 

[foxflyer2]

Thanks Dynon Support! If you indeed have a bug which is missing the alpha designations, it will be great if you can fix it and include Lake Elmo AWOS weather in your ADS-B receptions.

 

[jc2da]

Was KHAF affected by this bug?

I have been holding off on the ADS-B module mainly because it never recognized weather from our AWOS, which is reported by AWS.

http://aviationweather.gov/adds/metars/?station_ids=khaf&std_trans=standard&chk_metars=on&hoursStr=most+recent+only&submitmet=Submit

 

[dynonsupport]

KHAF is both the official FAA ident and the METAR ID, so KHAF should show up fine.

What data do you have that says it isn't shown via ADS-B?

 

[dynonsupport]

For future posterity, this was fixed in SkyView release 10.0.