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  #1  
Old 02-08-2019, 09:21 AM
RandyAB RandyAB is offline
 
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Location: St Albert, Alberta, Canada
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Default Aireon space based ADS-B

I sent a note to Garmin but I thought I would throw this out to the group Iím case others have insight or alternatively, a similar question. For the space based Aireon system that is going to be utilized in Canada for ADS-B, is the standard Garmin GTX transponder install going to allow for full functionality or is additional equipment needed? I see that Aireon says a top mounted antenna is required. Is this a need or is it just desirable? If necessary, i would like to do it now. My understanding is that the system mostly caters to commercial aircraft and that GA is an afterthought. Clarification?
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  #2  
Old 02-08-2019, 11:18 AM
moosepileit moosepileit is offline
 
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I only find 2 current light GA type Diversity enabled transponders.

Good thread: http://forums.avidyne.com/diversity-...topic1589.html

Says the Garmin GTX 330D (ES version) supports Diversity. Note the "D" in the hardware model.

L-3's Lynx 9000NGTD, "D" for diversity, or top and bottom antennae, lists for $6300 USD as an all in one solution. 1090ES out with WAAS built in, ADS-B In and Out.

I assume these 2 types would be the "hope" for a reasonable, existing solution assuming this becomes a Canadian mandate. Would possibly have to know if use of both antennae is constant and compliant with the needs of the OP space-based system.

The issue I see is I believe WRT ATC transponder/radar, the diversity is controlled to give best performance from air to GROUND. No idea what software or hardware makes Aireon "happy".

Large aircraft have had diversity for transponders with TCAS for at least a generation. I assume that the upper and lower antennae receive simultaneoulsy and the software controls reply transmissions directed to the stronger receiving antenna.

Just the S.W.A.G. of a pilot, not engineer or avionics guru. Walt?

ETA, Garmin FAQ leads to assuming they offer antennae diversity on some options. No idea about the other manufacturers.

https://www.garmin.com/us/intheair/a...ven-questions/

"Why should I consider a dual (diversity) antenna installation for my ADS-B solution?
Antenna diversity technology configures your aircraft with both top- and bottom-mount antennas to reduce the potential for antenna “shading,” which helps prevent target drop out during turns and maneuvers. An optional top-mounted antenna also comes in handy during ground operations, when a bottom-mount mount antenna might not have clear line-of-sight to receive ADS-B ground station signals or transmissions from other participating aircraft."

The Aireon website does not even mention light GA.
https://aireon.com/resources/overvie...pecifications/
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Last edited by moosepileit : 02-08-2019 at 12:20 PM.
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  #3  
Old 02-08-2019, 12:57 PM
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Ed_Wischmeyer Ed_Wischmeyer is offline
 
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I think it requires an Iridium radio. Reasonably certain.
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  #4  
Old 02-08-2019, 01:06 PM
moosepileit moosepileit is offline
 
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Surveillance Datalink 1090ES ADS-B (DO-260 versions 0,1,2)

Aircraft Transmitter Classes Supported A1 or higher with a top-mount antenna

Rides on the 66 Sat Iridium constellation. No mention of needing anything termed Iridium on your aircraft.


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  #5  
Old 02-08-2019, 01:11 PM
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vlittle vlittle is offline
 
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An antenna mounted at a 45 degree angle to the longitudinal access and located on the 'stinger' position of the rudder would provide an almost 360x360 view of both ground and satellite stations.

Alternatively, if Microavionix would develop a dual mode ADS-B in + 1090es transponder for the stinger position, that would be ideal.
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Last edited by vlittle : 03-02-2019 at 09:20 AM.
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  #6  
Old 02-08-2019, 10:08 PM
RandyAB RandyAB is offline
 
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Thanks for the info guys and especially the links Moose. I got a reply from Garmin who said that a single bottom mounted UHF was all that was needed but I'm thinking that this is specific to the US with their ground stations. I asked them to clarify if is was still applicable to satellite based ADS-B.
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  #7  
Old 02-09-2019, 02:54 AM
JackZ JackZ is online now
 
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Location: neustadt ontario
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I sent an email to trig in the UK about this before purchasing a transponder. The response I got from them was that the waves can bend somewhat. The typical single mount transponder antenna if it is properly located (on the bottom of the fuselage behind the wing ) will work just fine. In Europe,diversity antenna is only required for larger aircraft where the waves would not bend enough for consistent coverage.
I purchased a trig tt22 and will be testing early this summer when my rv9a takes first flight.
Hope this helps

Jack
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  #8  
Old 02-09-2019, 04:45 AM
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Thermos Thermos is offline
 
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You'll certainly get a stronger signal to Aireon's satellite ADS-B receivers if you have a diversity transponder and an upper antenna. But they've released some early test data that show their receivers are sensitive enough to pick up ADS-B Out replies from aircraft with only a lower antenna.

Aireon's systems ride on Iridium Next satellites but no Iridium system is required on our airplanes...a 1090ES ADS-B Out transponder is all that's needed.

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Last edited by Thermos : 02-09-2019 at 04:49 AM.
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  #9  
Old 02-09-2019, 10:33 PM
RV-4 RV-4 is offline
 
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Location: St-Jerome,Quebec,Canada
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Question Space Based vs US Ground Based ADS-B

Hello Gents

I just read the previous posts and it was very informative but just to make it clear, if I wanna operate in Canada and the US, what type of Transponder do I need...

I was planning to install a GDL-82 with my GTX-327 so that I could fly in the US next year but don't wanna install something costing $$$$ if I have to install another one to fly in Canada..

Do Garmin or someone else have a TXPR that work on 978MHZ & 1090 MHZ making it a single box for both country??

Makes you wonder why the US didn't go with a 1090 MHZ system from the start like the rest of the world...

Thanks

Bruno
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  #10  
Old 02-10-2019, 08:05 AM
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Jesse Jesse is offline
 
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The US does run on 1090ES as well as UAT. The weather information is a UAT broadcast. Traffic is broadcast on either 1090 or UAT, depending on what the receiver can handle. 1090ES is the international standard and is required up in the flight levels.
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