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  #21  
Old 06-03-2015, 06:24 PM
BobTurner BobTurner is offline
 
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Quote:
Originally Posted by MarkW View Post
Ron,
I believe what you are saying is correct.
I have the Garmin G3x setup and i am sending out both. There were times that the FAA would drop me. Garmin has done a software upgrade to send out both but only tell the system that we are sending UAT. Now it is flawless.
The FAA has admitted to this problem.
I think you and Ron are talking about different things. You do not tell the FAA you are transmitting on 1090 or 978, you just do it. What you do tell them, in the ADSB-out signal, is if you have ADSB-in on 978, 1090, or both. And yes, I have heard that saying both has caused some issues; saying just 978 fixes it.

Ron, why would you pay for two "out" solutions? I do not the answer to your question, however, the system is supposed to already integrate ADSB targets and radar targets into one, so I would hope it would merge multiple ADSB signals, too.
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  #22  
Old 06-04-2015, 06:20 AM
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MarkW MarkW is online now
 
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Looks like you are correct Bob.
This whole ADS-B thing is a little fussy to me still. I am just glad I have it, it works and I am compliant for 2020.

Here is the explanation from Garmin.

http://www.vansairforce.com/communit...d.php?t=119844
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  #23  
Old 06-07-2015, 08:33 PM
BobTurner BobTurner is offline
 
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Quote:
Originally Posted by RONSIM View Post
If you were to install (or already have) a Mode S/ES transponder with 1090 out AND a UAT unit with 978 out, will there be some sort of conflict at the ATC end, or, with the receiver in the airplane?

Seems like I heard something that the FAA was not happy with that setup.

R.
I found the answer, this is addressed in AC20-165.

In short, an S-ES AND a UAT is not recommended but is acceptable, as long as:
there are single data entry points for squawk code, ident, AND
the UAT must be broadcasting your 24 bit code (mode S id). The UAT may not have the anonymous feature enabled, ATC would see that as two airplanes.

Two S-ES or two UAT's may NOT be operated at the same time.

Which brings up another question: the AC says ADSB-out must have an automatic air/ground determination method. All the S-Es transponders that I have seen discuss this (squat switch, pressure switch to determine some minimum IAS, air data computer input for minimum IAS...). But I have seen no discussion about air/ground switching for any UAT. Anyone know about this?
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  #24  
Old 06-08-2015, 03:42 PM
rwhittier rwhittier is offline
 
Join Date: Oct 2006
Location: Glendale, AZ
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Default Minimum speed toggles my UAT

Quote:
Originally Posted by BobTurner View Post

Which brings up another question: the AC says ADSB-out must have an automatic air/ground determination method. All the S-Es transponders that I have seen discuss this (squat switch, pressure switch to determine some minimum IAS, air data computer input for minimum IAS...). But I have seen no discussion about air/ground switching for any UAT. Anyone know about this?
The NavWorx ADS600B UAT installed in my not yet flying RV7A (the ADS-B system is installed and working) makes reference to a pin reserved for a future squat switch in the installation instructions. It uses minimum speed for air/ground determination. That must be coming from its own on board GPS since it has no other means to know speed.
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Last edited by rwhittier : 06-08-2015 at 06:14 PM. Reason: Correct typo
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  #25  
Old 06-08-2015, 04:09 PM
BobTurner BobTurner is offline
 
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Location: Livermore, CA
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Quote:
Originally Posted by rwhittier View Post
The NavWorx ADS600B UAT installed in my not yet flying RV7A (the ADS-B system is installed and working) makes reference to a pin reserved for a future squat switch in the installation instructions. It uses minimum speed for air/determination. That must be coming from its own on board GPS since it has no other means to know speed.
Interesting. The AC, which is not regulatory but rather 'demonstrates one acceptable means of compliance', suggests that using only gps (ground) speed 'has been demonstrated to be not satisfactory' as too many false change-overs occur (presumably slow aircraft, either climbing or on final approach, and into a headwind, can switch to ground while airborn due to a low ground speed). But they seem happy with using IAS, even though a strong headwind while taxiing could cause a false change to airborn mode.(?)
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