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ceengland7(at)gmail.com
Guest

Posted: Sat Nov 14, 2015 12:12 pm Post subject: Stratux Build

Sorry; I thought I'd read on the interwebs that the 330 would fit a 327 

tray, with just a few added pins. I guess I've discovered the first 

error on the 'net. 



Charlie



On 11/14/2015 9:44 AM, Bill Bradburry wrote:

[quote] 



 I think you can upgrade the GTX330 to the ES version for about $1K, but per

 the Q&A at AC Spruce the GTX327 tray and harness is not interchangeable.

 Will the GTX 330 ES fit the same rack as the GTX 327? How about the harness?

 The Garmin GTX 330 ES and the GTX 327 use both different racks and

 harnesses.



 Bill



 --

rampil

Joined: 04 May 2007
Posts: 870

Posted: Sun Nov 15, 2015 6:11 am Post subject: Re: Stratux Build

Just a Nota Bene:



I have reviewed the Pilot Aware docs and discovered the following:



1) It is not open source. In fact it requires a license code from the author.



2) It uses the iOS hardware GPS.  The GPS Chipset in an iPhone or 

iPad is not a certificated TSO location source, nor does it even meet

TSO specs.  Therefore it would not be legal to transmit data into the 

NAS in the US even under the lenient requirements for experimental 

aircraft.



3) It only does 1090 Extended squatter (for now). In the UK, ES is the 

only game in town. In the US most GA traffic is 978 Hz TISb.  So, in the US

PilotAware will show you mostly Transport Category stuff in the Flight Levels

but basically no traffic below FL180 (except near big airports).

_________________
Ira N224XS

Kellym

Joined: 10 Jan 2006
Posts: 1706
Location: Sun Lakes AZ

Posted: Sun Nov 15, 2015 8:36 am Post subject: Stratux Build

A large proportion of high performance GA aircraft have or will get 

1090ES because their aircraft can go above 18,000 and/or they already 

had a Garmin 330 and upgrade to ES is their cheapest option.

Of flight schools in Phoenix that have ADS-B (all the big ones) one uses 

978, the rest are all 1090ES.



On 11/15/2015 7:11 AM, rampil wrote:

 	  Quote: 	
		   



 Just a Nota Bene:



 I have reviewed the Pilot Aware docs and discovered the following:



 1) It is not open source. In fact it requires a license code from the author.



 2) It uses the iOS hardware GPS.  The GPS Chipset in an iPhone or

 iPad is not a certificated TSO location source, nor does it even meet

 TSO specs.  Therefore it would not be legal to transmit data into the

 NAS in the US even under the lenient requirements for experimental

 aircraft.



 3) It only does 1090 Extended squatter (for now). In the UK, ES is the

 only game in town. In the US most GA traffic is 978 Hz TISb.  So, in the US

 PilotAware will show you mostly Transport Category stuff in the Flight Levels

 but basically no traffic below FL180 (except near big airports).



 --------

 Ira N224XS





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=449410#449410

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

deej(at)deej.net
Guest

Posted: Sun Nov 15, 2015 9:12 am Post subject: Stratux Build

On 11/15/2015 9:11 AM, rampil wrote:

 	  Quote: 	
		   3) It only does 1090 Extended squatter (for now). In the UK, ES is the

 only game in town. In the US most GA traffic is 978 Hz TISb.  So, in the US

 PilotAware will show you mostly Transport Category stuff in the Flight Levels

 but basically no traffic below FL180 (except near big airports).


	




It would be interesting to see actual numbers, but my guess is that at 

present, most traffic in the US is on 1090 since most of the aircraft 

that are currently equipped are commercial and business.  There are also 

a likely large number of GA aircraft using 1090 as well, since they will 

want to do IFR at reasonably high altitudes.



As we get closer to 2020, we will likely see more GA traffic using 978, 

but my gut is telling me that the largest number of traffic overall will 

still be on 1090 for the reasons above.  There really doesn't seem to be 

an advantage to using 978 "Out" as far as I can see, but that does give 

good reasons for equipping with a dual band "In" so you can see both.



-Dj



-- 

Dj Merrill - N1JOV - EAA Chapter 87

Sportsman 2+2 Builder #7118 N421DJ - http://deej.net/sportsman/

Glastar Flyer N866RH - http://deej.net/glastar/

bbradburry(at)verizon.net
Guest

Posted: Sun Nov 15, 2015 11:41 am Post subject: Stratux Build

Are you saying that the FAA is not going to broadcast the "out" on both

freqs?  That makes absolutely not sense to me.

You will be just as dead no matter what airplane you run into.



With the possible exception of Wonder Woman's plane...  :>)   Does she have

to install ADS-B as well??



--

wrmaxwell(at)bigpond.com
Guest

Posted: Sun Nov 15, 2015 1:29 pm Post subject: Stratux Build

I think your Nota Bene         somewhat undersells Pilot Aware, Ira. It is not open-source but         the beta licence is free and once it enters the market, the         projected annual licence fee is very, very cheap. It can use the         iOS GPS but it can equally use any other GPS. In fact, an         external GPS is now the developer's preference. I take your         point that it might not suit the US at the present time but the         potential is there for most locations, provided they solve the         ISM transmitter issues and there is widespread adoption so that         lower level traffic use it and therefore can be seen.

         

         Bill.

     

     On 16/11/2015 1:11 AM, rampil wrote:

     

      	  Quote: 	
		          	  Quote: 	
		  --> AeroElectric-List message posted by: "rampil" <ira.rampil(at)gmail.com> (ira.rampil(at)gmail.com)



Just a Nota Bene:



I have reviewed the Pilot Aware docs and discovered the following:



1) It is not open source. In fact it requires a license code from the author.



2) It uses the iOS hardware GPS.  The GPS Chipset in an iPhone or 

iPad is not a certificated TSO location source, nor does it even meet

TSO specs.  Therefore it would not be legal to transmit data into the 

NAS in the US even under the lenient requirements for experimental 

aircraft.



3) It only does 1090 Extended squatter (for now). In the UK, ES is the 

only game in town. In the US most GA traffic is 978 Hz TISb.  So, in the US

PilotAware will show you mostly Transport Category stuff in the Flight Levels

but basically no traffic below FL180 (except near big airports).



--------

Ira N224XS





Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=449410#449410

Kellym

Joined: 10 Jan 2006
Posts: 1706
Location: Sun Lakes AZ

Posted: Sun Nov 15, 2015 4:16 pm Post subject: Stratux Build

Your out signal contains what type of In receiver you have, and the 

ground station sends you data on your freq. Mostly a moot point for the 

ground stations...1090 does not have bandwith for more than TIS-A, so 

you get no weather or TIS-B traffic unless you have 978 receiver. Way 

more complex than it needed to be.



On 11/15/2015 12:40 PM, Bill Bradburry wrote:

[quote] 



 Are you saying that the FAA is not going to broadcast the "out" on both

 freqs?  That makes absolutely not sense to me.

 You will be just as dead no matter what airplane you run into.



 With the possible exception of Wonder Woman's plane...  :>)   Does she have

 to install ADS-B as well??



 --

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

rampil

Joined: 04 May 2007
Posts: 870

Posted: Sun Nov 15, 2015 5:39 pm Post subject: Re: Stratux Build

Hi Bill,



I noted the discrepancy about Open Source because the original poster Clive

described it as such.



I have not seen any hard data about the division between  1090 and 978.

However, I have been using a dual receiver Stratux for more than a month.

In my neck of the woods, the traffic I see is airline and corporate on 1090

and the traffic doing less than 300 kts is all 978.  Time will tell.



1090 traffic received by an aircraft receiver is solely direct transmission from other aircraft in range.

978 traffic is a combination of direct reception from other aircraft plus 

ground-based retransmission of targets both 978 and 1090. (Not to 

mention the FISb data)

_________________
Ira N224XS

stephencliverichards(at)g
Guest

Posted: Mon Nov 16, 2015 4:24 am Post subject: Stratux Build

Hi Ira                  I am sorry for my mistake I should have written Open Hardware I have been following the topic on the Flyer Forum and got my misconception from their.   As some of the other posters on the list were looking for ADSB out I thought it might be worth a look, any grade GPS could be used. If the concept  is of any use to add to Stratus Pi they could write their own code. Our CAA are conducting trials at the moment  using uncertified GPS. There are not a lot of Certified GA aircraft in UK with Mode S transponders using ES because it is a Major mod to connect the two wires to a certified GPS.  I will build one when the transmit is sorted out as due to low cost I think a lot of pilots will take it up and we will be able to see each other + ES traffic.           A lot of pilots are now using Tablets with navigation software like Skydemon or Easy VFR and GPS work with no problem  this is where the traffic would be displayed.

Clive

On 16 November 2015 at 01:39, rampil <ira.rampil(at)gmail.com (ira.rampil(at)gmail.com)> wrote:

 	  Quote: 	
		  --> AeroElectric-List message posted by: "rampil" <ira.rampil(at)gmail.com (ira.rampil(at)gmail.com)>

 

 Hi Bill,

 

 I noted the discrepancy about Open Source because the original poster Clive

 described it as such.

 

 I have not seen any hard data about the division between  1090 and 978.

 However, I have been using a dual receiver Stratux for more than a month.

 In my neck of the woods, the traffic I see is airline and corporate on 1090

 and the traffic doing less than 300 kts is all 978.  Time will tell.

 

 1090 traffic received by an aircraft receiver is solely direct transmission from other aircraft in range.

 978 traffic is a combination of direct reception from other aircraft plus

 ground-based retransmission of targets both 978 and 1090. (Not to

 mention the FISb data)

 

 --------

 Ira N224XS

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=449511#449511

 

 

 

 

 

 

 

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rampil

Joined: 04 May 2007
Posts: 870

Posted: Mon Nov 16, 2015 5:18 am Post subject: Re: Stratux Build

As things stand at the moment in the US domain, there are multiple distinct

hurdles to homebuilding ADSB-Out



1) The first is that microwave (near 1 GHz) circuit design and construction

is complex, much more so than VHF. Not to say it can't be done, but 

it requires expert level skill set. There some UHF amateur radio folks who

are proficient, but it is way different than command line hacking a RaspPi.



2) Outside of the ham bands, transmitters of this power output require FCC

certification for a variety of specs including frequency spread, power output, stability, etc. 



3) Any transmitter sending data into the NAS (National Airspace System)

requires FAA TSO or, for OBAM and gliders, as I understand the current state 

of affairs, meeting TSO spec without actual certification. The specs are

onerous to meet, needless to say.



You get around 1-3 by using a commercial transponder which will take

position data and transmit 1090ES in a regulatory approved manner.



4) So far as I can determine, it is mandatory in the US to use a certified

position source to feed the 1090ES. I'd be shocked to discover that the EU

is less discerning about positional accuracy. I'm not saying that the specs 

of a cheap chip set like the RY835 aren't good, they just are not

certified for TSO for ADSB out (so far as I know, and I have read their docx).

_________________
Ira N224XS

Kellym

Joined: 10 Jan 2006
Posts: 1706
Location: Sun Lakes AZ

Posted: Mon Nov 16, 2015 6:59 am Post subject: Stratux Build

The best comparison of what it takes is the Dynon Skyview system. They 

started with a Trig 1090ES transponder, and had EFIS and moving map 

running of commercial grade GPS WAAS chips, with the GPS unit costing 

$200 retail. To meet the 2020 requirement, after the FAA clarified that 

the GPS had to meet TSO performance specs, but did not need actual TSO  

approval for experimental OBAM aircraft; Dynon designed a GPS that had 

all the integrity checking features the TSO called for, and is now 

offering a "certified" grade GPS that will be legal in US for 2020, at 

retail cost of $590. Combined cost of the Trig transponder and the legal 

GPS is around $2700 on top of the cost of the EFIS. Not bad, but more 

than the Freeflight combination UAT and WAAS GPS unit that is TSO 

approved priced around $2000 plus install.



On 11/16/2015 6:18 AM, rampil wrote:

 	  Quote: 	
		   



 As things stand at the moment in the US domain, there are multiple distinct

 hurdles to homebuilding ADSB-Out



 1) The first is that microwave (near 1 GHz) circuit design and construction

 is complex, much more so than VHF. Not to say it can't be done, but

 it requires expert level skill set. There some UHF amateur radio folks who

 are proficient, but it is way different than command line hacking a RaspPi.



 2) Outside of the ham bands, transmitters of this power output require FCC

 certification for a variety of specs including frequency spread, power output, stability, etc.



 3) Any transmitter sending data into the NAS (National Airspace System)

 requires FAA TSO or, for OBAM and gliders, as I understand the current state

 of affairs, meeting TSO spec without actual certification. The specs are

 onerous to meet, needless to say.



 You get around 1-3 by using a commercial transponder which will take

 position data and transmit 1090ES in a regulatory approved manner.



 4) So far as I can determine, it is mandatory in the US to use a certified

 position source to feed the 1090ES. I'd be shocked to discover that the EU

 is less discerning about positional accuracy. I'm not saying that the specs

 of a cheap chip set like the RY835 aren't good, they just are not

 certified for TSO for ADSB out (so far as I know, and I have read their docx).



 --------

 Ira N224XS





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=449514#449514

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

rd2(at)dejazzd.com
Guest

Posted: Mon Nov 16, 2015 7:48 am Post subject: Stratux Build

Just wondering - could the same $590 "certified" GPS (antenna) be used to simultaneously feed a X-ponder and 430W or GTN650 with a splitter ? 

(instead of feeding the X-ponder from the 430W; the reasoning is to remain ADS-B compliant in case the 430W is temporarily removed)



---- Kelly McMullen <kellym(at)aviating.com> wrote: 



=============




The best comparison of what it takes is the Dynon Skyview system. They 

started with a Trig 1090ES transponder, and had EFIS and moving map 

running of commercial grade GPS WAAS chips, with the GPS unit costing 

$200 retail. To meet the 2020 requirement, after the FAA clarified that 

the GPS had to meet TSO performance specs, but did not need actual TSO  

approval for experimental OBAM aircraft; Dynon designed a GPS that had 

all the integrity checking features the TSO called for, and is now 

offering a "certified" grade GPS that will be legal in US for 2020, at 

retail cost of $590. Combined cost of the Trig transponder and the legal 

GPS is around $2700 on top of the cost of the EFIS. Not bad, but more 

than the Freeflight combination UAT and WAAS GPS unit that is TSO 

approved priced around $2000 plus install.



On 11/16/2015 6:18 AM, rampil wrote:

 	  Quote: 	
		   



 As things stand at the moment in the US domain, there are multiple distinct

 hurdles to homebuilding ADSB-Out



 1) The first is that microwave (near 1 GHz) circuit design and construction

 is complex, much more so than VHF. Not to say it can't be done, but

 it requires expert level skill set. There some UHF amateur radio folks who

 are proficient, but it is way different than command line hacking a RaspPi.



 2) Outside of the ham bands, transmitters of this power output require FCC

 certification for a variety of specs including frequency spread, power output, stability, etc.



 3) Any transmitter sending data into the NAS (National Airspace System)

 requires FAA TSO or, for OBAM and gliders, as I understand the current state

 of affairs, meeting TSO spec without actual certification. The specs are

 onerous to meet, needless to say.



 You get around 1-3 by using a commercial transponder which will take

 position data and transmit 1090ES in a regulatory approved manner.



 4) So far as I can determine, it is mandatory in the US to use a certified

 position source to feed the 1090ES. I'd be shocked to discover that the EU

 is less discerning about positional accuracy. I'm not saying that the specs

 of a cheap chip set like the RY835 aren't good, they just are not

 certified for TSO for ADSB out (so far as I know, and I have read their docx).



 --------

 Ira N224XS





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=449514#449514

edpav8r(at)yahoo.com
Guest

Posted: Mon Nov 16, 2015 8:23 am Post subject: Stratux Build

Assuming Dynon's GPS outputs standard NEMA sentences over serial comm (they don't have a proprietary data stream) it should be possible.  Being a position source itself, does the 430W have provision for position input?



Does anyone know if, or how, the Feds' ADS-B ground system verifies that data it receives from airborne sources is coming from a compliant position source?  Does the data stream contain a model-specific code that's compared against an approved list?  Or, is compliance enforced like the requirement for a pilot license (i.e. by ramp check)?  And no, I'm not advocating $10 eBay GPS receivers! 



Eric

 	  Quote: 	
		   On Nov 16, 2015, at 7:46 AM, <rd2(at)dejazzd.com> <rd2(at)dejazzd.com> wrote:

 Just wondering - could the same $590 "certified" GPS (antenna) be used to simultaneously feed a X-ponder and 430W or GTN650 with a splitter (instead of feeding the X-ponder from the 430W; the reasoning is to remain ADS-B compliant in case the 430W is temporarily removed)?

Tim Olson

Joined: 25 Jan 2007
Posts: 2881

Posted: Mon Nov 16, 2015 11:00 am Post subject: Stratux Build

One thing I have been curious about lately is something I heard

about back a couple years before ADS-B really took off.

I've been running a 978 system since 2009 now, and I personally

think it makes the most sense for 85%+ all of the piston

singles.  That said, I think that ideally all systems would

be dual receive.  I queried NavWorX about the ADS600B that I have

and it does sound like they intend to add 1090 In to the box

also, to make it a dual receive system, which will be a good thing.



The thing I'm curious about is that I was told by a couple

people within the avionics indrustry that were well knowing,

that the 1090 Mhz system was already fairly "busy" and

nearing saturation for what that frequency could handle for

these communications.  It was said at the time basically,

to paraphrase a memory "If every aircraft equipped with

1090 out, it would bring the system to it's knees."



So if that's true, I am surprised we haven't seen any

rulemaking or guidance to the consumer that they should

equip with the most *appropriate* system for their

aircraft.  So if you are a small GA aircraft owner, who

has a plane that won't be flying above the 978mhz ceiling,

you use that 978mhz system by default.  Maybe they just

assumed that so many pilots would want the 978Mhz systems

anyway, for the free weather products?  When getting my Ham

radio license, it was clear that to be radio frequency

friendly that you don't unnecessarily broadcast things

that could interfere, and if the 1090 system is really

that saturated already, I certainly don't need to broadcast

there.



So is there truth the saturation issue, or not?



Tim

On 11/15/2015 11:09 AM, Dj Merrill wrote:

 	  Quote: 	
		   



 On 11/15/2015 9:11 AM, rampil wrote:

> 3) It only does 1090 Extended squatter (for now). In the UK, ES is the

> only game in town. In the US most GA traffic is 978 Hz TISb.  So, in

> the US

> PilotAware will show you mostly Transport Category stuff in the Flight

> Levels

> but basically no traffic below FL180 (except near big airports).

 It would be interesting to see actual numbers, but my guess is that at

 present, most traffic in the US is on 1090 since most of the aircraft

 that are currently equipped are commercial and business.  There are also

 a likely large number of GA aircraft using 1090 as well, since they will

 want to do IFR at reasonably high altitudes.



 As we get closer to 2020, we will likely see more GA traffic using 978,

 but my gut is telling me that the largest number of traffic overall will

 still be on 1090 for the reasons above.  There really doesn't seem to be

 an advantage to using 978 "Out" as far as I can see, but that does give

 good reasons for equipping with a dual band "In" so you can see both.



 -Dj

ceengland7(at)gmail.com
Guest

Posted: Mon Nov 16, 2015 11:51 am Post subject: Stratux Build

On November 16, 2015 12:58:37 PM CST, Tim Olson <Tim(at)MyRV10.com> wrote:[quote] [quote]--> AeroElectric-List message posted by: Tim Olson <Tim(at)myrv10.com>One thing I have been curious about lately is something I heardabout back a couple years before ADS-B really took off.I've been running a 978 system since 2009 now, and I personallythink it makes the most sense for 85%+ all of the pistonsingles.  That said, I think that ideally all systems wouldbe dual receive.  I queried NavWorX about the ADS600B that I haveand it does sound like they intend to add 1090 In to the boxalso, to make it a dual receive system, which will be a good thing.The thing I'm curious about is that I was told by a couplepeople within the avionics indrustry that were well knowing,that the 1090 Mhz system was already fairly "busy" andnearing saturation for what that frequency could handle forthese communications.  It was said at the time basically,to paraphrase a memory   "If every aircraft equipped with1090 out, it would bring the system to it's knees."So if that's true, I am surprised we haven't seen anyrulemaking or guidance to the consumer that they shouldequip with the most *appropriate* system for theiraircraft.  So if you are a small GA aircraft owner, whohas a plane that won't be flying above the 978mhz ceiling,you use that 978mhz system by default.  Maybe they justassumed that so many pilots would want the 978Mhz systemsanyway, for the free weather products?  When getting my Hamradio license, it was clear that to be radio frequencyfriendly that you don't unnecessarily broadcast thingsthat could interfere, and if the 1090 system is reallythat saturated already, I certainly don't need to broadcastthere.So is there truth the saturation issue, or not?TimOn 11/15/2015 11:09 AM, Dj Merrill wrote:[quote] --> AeroElectric-List message posted by: Dj Merrill <deej(at)deej.net> On 11/15/2015 9:11 AM, rampil wrote: 	  Quote: 	
		   3) It only does 1090 Extended squatter (for now). In the UK, ES is the only game in town. In the US most GA traffic is 978 Hz TISb.  So, in the US PilotAware will show you mostly Transport Category stuff in the Flight Levels but basically no traffic below FL180 (except near big airports). 	
 It would be interesting to see actual numbers, but my guess is that at present, most traffic in the US is on 1090 since most of the aircraft that are currently equipped are commercial and business.  There are also a likely large number of GA aircraft using 1090 as   well,       - -- 

 Sent from my Android device with K-9 Mail. Please excuse my brevity.

ceengland7(at)gmail.com
Guest

Posted: Mon Nov 16, 2015 11:56 am Post subject: Stratux Build

On November 16, 2015 12:58:37 PM CST, Tim Olson <Tim(at)MyRV10.com> wrote:[quote] [quote]--> AeroElectric-List message posted by: Tim Olson <Tim(at)myrv10.com>One thing I have been curious about lately is something I heardabout back a couple years before ADS-B really took off.I've been running a 978 system since 2009 now, and I personallythink it makes the most sense for 85%+ all of the pistonsingles.  That said, I think that ideally all systems wouldbe dual receive.  I queried NavWorX about the ADS600B that I haveand it does sound like they intend to add 1090 In to the boxalso, to make it a dual receive system, which will be a good thing.The thing I'm curious about is that I was told by a couplepeople within the avionics indrustry that were well knowing,that the 1090 Mhz system was already fairly "busy" andnearing saturation for what that frequency could handle forthese communications.  It was said at the time basically,to paraphrase a memory   "If every aircraft equipped with1090 out, it would bring the system to it's knees."So if that's true, I am surprised we haven't seen anyrulemaking or guidance to the consumer that they shouldequip with the most *appropriate* system for theiraircraft.  So if you are a small GA aircraft owner, whohas a plane that won't be flying above the 978mhz ceiling,you use that 978mhz system by default.  Maybe they justassumed that so many pilots would want the 978Mhz systemsanyway, for the free weather products?  When getting my Hamradio license, it was clear that to be radio frequencyfriendly that you don't unnecessarily broadcast thingsthat could interfere, and if the 1090 system is reallythat saturated already, I certainly don't need to broadcastthere.So is there truth the saturation issue, or not?TimOn 11/15/2015 11:09 AM, Dj Merrill wrote:[quote] --> AeroElectric-List message posted by: Dj Merrill <deej(at)deej.net> On 11/15/2015 9:11 AM, rampil wrote: 	  Quote: 	
		   3) It only does 1090 Extended squatter (for now). In the UK, ES is the only game in town. In the US most GA traffic is 978 Hz TISb.  So, in the US PilotAware will show you mostly Transport Category stuff in the Flight Levels but basically no traffic below FL180 (except near big airports). 	
 It would be interesting to see actual numbers, but my guess is that at present, most traffic in the US is on 1090 since most of the aircraft that are currently equipped are commercial and business.  There are also a likely large number of GA aircraft using 1090 as   well,       - -- 

 Sent from my Android device with K-9 Mail. Please excuse my brevity.

ceengland7(at)gmail.com
Guest

Posted: Mon Nov 16, 2015 4:55 pm Post subject: Stratux Build

On 11/16/2015 1:48 PM, Charlie England       wrote:

     

      	  Quote: 	
		         On November 16, 2015 12:58:37 PM CST, Tim         Olson <Tim(at)MyRV10.com> (Tim(at)MyRV10.com) wrote:          	  Quote: 	
		              	  Quote: 	
		  --> AeroElectric-List message posted by: Tim Olson <Tim(at)myrv10.com> (Tim(at)myrv10.com)



One thing I have been curious about lately is something I heard

about back a couple years before ADS-B really took off.

I've been running a 978 system since 2009 now, and I personally

think it makes the most sense for 85%+ all of the piston

singles.  That said, I think that ideally all systems would

be dual receive.  I queried NavWorX about the ADS600B that I have

and it does sound like they intend to add 1090 In to the box

also, to make it a dual receive system, which will be a good thing.



The thing I'm curious about is that I was told by a couple

people within the avionics indrustry that were well knowing,

that the 1090 Mhz system was already fairly "busy" and

nearing saturation for what that frequency could handle for

these communications.  It was said at the time basically,

to paraphrase a memory "If

every aircraft equipped with

1090 out, it would bring the system to it's knees."



So if that's true, I am surprised we haven't seen any

rulemaking or guidance to the consumer that they should

equip with the most *appropriate* system for their

aircraft.  So if you are a small GA aircraft owner, who

has a plane that won't be flying above the 978mhz ceiling,

you use that 978mhz system by default.  Maybe they just

assumed that so many pilots would want the 978Mhz systems

anyway, for the free weather products?  When getting my Ham

radio license, it was clear that to be radio frequency

friendly that you don't unnecessarily broadcast things

that could interfere, and if the 1090 system is really

that saturated already, I certainly don't need to broadcast

there.



So is there truth the saturation issue, or not?



Tim

On 11/15/2015 11:09 AM, Dj Merrill wrote:

 	  Quote: 	
		   --> AeroElectric-List message posted by: Dj Merrill <deej(at)deej.net> (deej(at)deej.net)



 On 11/15/2015 9:11 AM, rampil wrote:

 	  Quote: 	
		   3) It only does 1090 Extended squatter (for now). In the UK, ES is the

 only game in town. In the US most GA traffic is 978 Hz TISb.  So, in

 the US

 PilotAware will show you mostly Transport Category stuff in the Flight

 Levels

 but basically no traffic below FL180 (except near big airports).

	




 It would be interesting to see actual numbers, but my guess is that at

 present, most traffic in the US is on 1090 since most of the aircraft

 that are currently equipped are commercial and business.  There are also

 a likely large number of GA aircraft using 1090 as well,

since they will

 want to do IFR at reasonably high altitudes.



 As we get closer to 2020, we will likely see more GA traffic using 978,

 but my gut is telling me that the largest number of traffic overall will

 still be on 1090 for the reasons above.  There really doesn't seem to be

 an advantage to using 978 "Out" as far as I can see, but that does give

 good reasons for equipping with a dual band "In" so you can see both.



 -Dj 	


	
         	
       

       Shouldn't be too hard to do the math. How many micro seconds does       each squit occupy & how many Micro seconds must the       transponder listen before squitting? The 'window' could be many       seconds wide, so if there's, say, a 5 million micro second window       and a 50 micro second 'listen/squit' interval, that would be room       for 100,000 planes.

       -- 

       Sent from my Android device with K-9 Mail. Please excuse my       brevity.     	
     

     Followup; just found a pdf comparing ES to mode A & C. max time     according to the doc is ~120 uSeconds, & a/c transmit once per     second, without interrogation.  So, if we roughly double that to 250     uSeconds & assume a 1 second repetition rate, that's     1,000,000/250= only 4000 planes in a given area. If we halve that     again to be really conservative, it's still 2k planes in an area.

     

     Link to the doc (1st one I landed on):

     http://www.ssd.dhmi.gov.tr/getBinaryFile.aspx?Type=3&dosyaID=195

     

     Charlie

richard.beebe(at)yale.edu
Guest

Posted: Tue Nov 17, 2015 7:04 am Post subject: Stratux Build

For Experimental Aircraft, the Navworx ADS600-EXP is a self-contained 

ADS-B in and out for about $1200. The ADS600-B at $1999 is for certified 

aircraft and seems very similar to the FreeFlight unit. However the 

Navworx units are both in and out and for $100 you can add wifi to 

display traffic & weather on a tablet. The $1999 FreeFlight unit is out 

only. Their in/out box is $3700.



I went to an ADS-B seminar on Sunday and the presenter said that Mexico 

is going to require 1090ES. I haven't been able to verify that, however. 

Just another datapoint if you're trying to decide on UAT vs 1090ES.



Something else I hadn't realized--for those thinking they can avoid 

airspace where you need ADS-B out--is that you can't fly over the top of 

any Class-B (actually the mode C veil) without ADS-B because the veil 

extends to 10,000' and ADS-B is required (in most places) above 10,000'. 

In my part of the country that's a significant inconvenience.



--Rick



On 11/16/2015 09:57 AM, Kelly McMullen wrote:

 	  Quote: 	
		   

 <kellym(at)aviating.com>



 The best comparison of what it takes is the Dynon Skyview system. They

 started with a Trig 1090ES transponder, and had EFIS and moving map

 running of commercial grade GPS WAAS chips, with the GPS unit costing

 $200 retail. To meet the 2020 requirement, after the FAA clarified that

 the GPS had to meet TSO performance specs, but did not need actual TSO

 approval for experimental OBAM aircraft; Dynon designed a GPS that had

 all the integrity checking features the TSO called for, and is now

 offering a "certified" grade GPS that will be legal in US for 2020, at

 retail cost of $590. Combined cost of the Trig transponder and the legal

 GPS is around $2700 on top of the cost of the EFIS. Not bad, but more

 than the Freeflight combination UAT and WAAS GPS unit that is TSO

 approved priced around $2000 plus install.

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