Today's Message Index:
----------------------
0. 10:04 AM - List Contribution - Value of the List... (Matt Dralle)
1. 04:24 AM - Re: Re: Stratux Build (Clive Richards)
2. 05:19 AM - Re: Stratux Build (rampil)
3. 06:59 AM - Re: Re: Stratux Build (Kelly McMullen)
4. 07:48 AM - Re: Re: Stratux Build ()
5. 08:23 AM - Re: Re: Stratux Build (Eric Page)
6. 11:00 AM - Re: Re: Stratux Build (Tim Olson)
7. 11:51 AM - Re: Re: Stratux Build (Charlie England)
8. 11:56 AM - Re: Re: Stratux Build (Charlie England)
9. 04:55 PM - Re: Re: Stratux Build (Charlie England)
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| Subject: | List Contribution - Value of the List... |
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| Subject: | Re: 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@gmail.com> wrote:
>
> 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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| 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
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=449514#449514
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| Subject: | Re: 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:
>
> 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
>
>
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| Subject: | Re: 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@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:
>
> 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
>
>
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| Subject: | Re: 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
> On Nov 16, 2015, at 7:46 AM, <rd2@dejazzd.com> <rd2@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)?
Message 6
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| Subject: | Re: 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:
>
> 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
>
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| Subject: | Re: Stratux Build |
On November 16, 2015 12:58:37 PM CST, Tim Olson <Tim@MyRV10.com> wrote:
>
>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:
>>
>> 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
>>
>
>
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.
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| Subject: | Re: Stratux Build |
On November 16, 2015 12:58:37 PM CST, Tim Olson <Tim@MyRV10.com> wrote:
>
>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:
>>
>> 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
>>
>
>
Slould have added, it *is* true that mode C can get saturated (mode c disable
instructions at SNF, OSH, etc), but that's likely because a ground radar sweep
triggers every transponder in its beam at once.
--
Sent from my Android device with K-9 Mail. Please excuse my brevity.
Message 9
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| Subject: | Re: Stratux Build |
On 11/16/2015 1:48 PM, Charlie England wrote:
> On November 16, 2015 12:58:37 PM CST, Tim Olson <Tim@MyRV10.com> wrote:
>
>
> 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:
>
> <deej@deej.net> 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
>
>
> 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
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