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  #11  
Old 11-03-2019, 04:20 PM
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Thermos Thermos is offline
 
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Quote:
Originally Posted by moosepileit View Post
The FAA picked a bad title for that webpage, as it doesn't show ADS-B ground segment availability. It shows areas where TSO C129 (ie., non-WAAS) GPS receivers have sufficient integrity to be used as position sources for ADS-B Out.

HTH

Dave
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Last edited by Thermos : 11-03-2019 at 04:26 PM.
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  #12  
Old 11-03-2019, 04:31 PM
maus92 maus92 is offline
 
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Location: Annapolis MD
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Only the "Out" side is mandated. The 'In" is basically an enhancement, thus optional.
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  #13  
Old 11-03-2019, 04:34 PM
BobTurner BobTurner is online now
 
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Location: Livermore, CA
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Quote:
Originally Posted by Thermos View Post
The FAA picked a bad title for that webpage, as it doesn't show ADS-B ground segment availability. It shows areas where TSO C129 (ie., non-WAAS) GPS receivers have sufficient integrity to be used as position sources for ADS-B Out.

HTH

Dave
I must be confused. I thought Non-WAAS boxes never had sufficient accuracy for ADSB use.
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  #14  
Old 11-04-2019, 05:44 AM
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Thermos Thermos is offline
 
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Quote:
Originally Posted by BobTurner View Post
I must be confused. I thought Non-WAAS boxes never had sufficient accuracy for ADSB use.
With enough satellites in view, non-WAAS GPS receivers *might* have sufficient accuracy and integrity for ADS-B Out over the time and route of your flight but you'd have to use a coverage prediction tool to know for sure - and that's what this website provides. WAAS differential corrections and automatic integrity monitoring eliminate the need for predictions.

The FAA granted US airlines a five-year exemption from the WAAS requirement so they can use their older GPSs for ADS-B Out while updating aircraft to meet the ADS-B requirement. They'll be required to run these predictions for each flight by a non-WAAS aircraft in ADS-B airspace. Unfortunately, this exemption doesn't apply to GA.

HTH

Dave
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  #15  
Old 11-11-2019, 12:39 AM
ron sterba ron sterba is offline
 
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Location: salem Oregon
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Could it be a line of sight frequency on the rebroadcast positioning data. Maybe a new building was built near the ground base antenna. Segmented airspace broadcasting might exist. Also data to the antenna might be interrupted through copper wire cable or fiber fed facilities . I had a strange thing happen when monitoring the GTN650 /ADSB ABOUT FOUR YEARS AGO. Just departed the class “D” airport and was passing a 700’ High country hill when another aircraft inbound passed to my right BuUT DIDNT SHOW UP ON MY ADSB SCREEN,! What,!! The other Aircraft did not have ADSB out but did have a working transponder but the FAA radar couldn’t pick up the transponder signal because we were behind the hill and therefore they could not re-broadcast the position of the other aircraft with just the transponder. Had We been in position a mile farther out or a mile before the hill I was told I would’ve received a re-broadcast signal from the other aircraft transponder by the FAA broadcast tower. I primarily look for other aircraft visually NOW and appreciate the added ADSB added position report info.
Ron in Oregon. RV9A the grandma GRANDPA AIRPLANE,
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  #16  
Old 11-12-2019, 05:48 AM
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bjdecker bjdecker is offline
 
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Location: Georgetown, TX
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Default TIS-B Update, a tale of two towers...

Ron,

As my father-in-law says "You can watch the dog run away for 2 days..."
-- it's comparatively flat terrain-wise in Central Texas.

Your point about radar coverage is spot on. If ASR/ARSR/ATCBI doesn't "see" and correlate a target (primary + secondary), that data won't make it to the TIS-B rebroadcast and therefore "disappear" from your display.

This issue is something more fundamental, our TIS-B receivers are not allowed to receive TIS-B service (Client is 0%).

TIS-B Service DID function on 11/1 and 11/9.

I have observed my GTX-345 flip between tower sites and TIS-B service availability come & go during that transition; roughly midway between two tower sites (see http://towers.stratux.me/ ) in San Angelo, TX and Round Rock, TX. At 9500' the aircraft is able to receive a number of towers, and it will use the data received from the site with the best signal strength/quality.

More email sent to ADS-B program director at FAA and response received, but no update on root cause -- yet.

B
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2020 RV-14 QB -- Under construction - Tailcone & Empennage Complete.
2018 RV-7 QB -- Built, Flying
2007 RV-7 QB -- Built, Drowned, Resurrected and flying
1998 RV-8 QB -- Started, Sold
1986 Mooney 205SE
1980 Mooney 231

Aided and abetted building a number of other RV's.
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  #17  
Old 11-12-2019, 06:29 AM
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Ed_Wischmeyer Ed_Wischmeyer is offline
 
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It took a while for my observations at KSAV to generate any action. Tower reported that all the hardware checked out properly, ASRS report went nowhere. Turns out it was a software problem and the hardware was working properly, just doing things incorrectly...

Finally I got the adsb@faa.gov email address. That email was complete in factual data and I also tossed in a bunch of extraneous but true BS about my career to give the report more weight...

Ed
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Previously RV-4, RV-8, RV-8A, AirCam, Cessna 175
ATP CFII PhD, so I have no excuses when I screw up
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Retired - "They used to pay me to be good, now I'm good for nothing."
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  #18  
Old 11-22-2019, 01:42 PM
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bjdecker bjdecker is offline
 
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Default Fixed...

I got an email back from the FAA --

--
After receiving several independent pilot reports (and the associated details), we were able to determine that a recent ADS-B maintenance action caused a software anomaly that resulted in unreliable delivery of TIS-B ?Service Status? messages in the region where you were flying. The avionics would then interpret the lack of the TIS-B Service Status message as the TIS-B Service being unavailable. However, the TIS-B Targets were still being sent by the ADS-B system and received by the avionics. The ADS-B maintenance procedures have been modified to eliminate the anomaly in the future.
--

So I guess it's fixed now...
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Brian Decker
Retired Firmware Guy and Airplane Builder

2020 RV-14 QB -- Under construction - Tailcone & Empennage Complete.
2018 RV-7 QB -- Built, Flying
2007 RV-7 QB -- Built, Drowned, Resurrected and flying
1998 RV-8 QB -- Started, Sold
1986 Mooney 205SE
1980 Mooney 231

Aided and abetted building a number of other RV's.
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