Potential ADS-B Out CAA Mandate
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Vlad Belayev
Oct 6, 2025, 4:33:53 PMOct 6
to SoftRF_community
So guys, CAA in the UK are Consulting regarding a mandate for any manned aircraft < 140kn speed to carry ADS-B out equipment.
That would include paragliders and sailplanes.
What are you views? A bit of overkill?
Manned specific Position 4. Within non - segregated airspace, aircraft operating at <140 knots (Kts) IAS must use 1090MHz ADS-B devices emitting a SIL and SDA of at least 1, such as (for example) some CAP1391 devices, alternatively a TSO�C112 and TSO-C166 compliant transponder with extended squitter connected to TSO-C199 class B or TSO-C145 GNSS source. CAP3140 Electronic Conspicuity – Initial Technical Concept of Operations (EC ConOps) 2025
That would include paragliders and sailplanes.
What are you views? A bit of overkill?
Manned specific Position 4. Within non - segregated airspace, aircraft operating at <140 knots (Kts) IAS must use 1090MHz ADS-B devices emitting a SIL and SDA of at least 1, such as (for example) some CAP1391 devices, alternatively a TSO�C112 and TSO-C166 compliant transponder with extended squitter connected to TSO-C199 class B or TSO-C145 GNSS source. CAP3140 Electronic Conspicuity – Initial Technical Concept of Operations (EC ConOps) 2025
Tony Taylor
Oct 6, 2025, 4:48:57 PMOct 6
to Vlad Belayev, SoftRF_community
ADS-L is just about to become the EU standard for U-Space... if UK wants to implement aerial BREXIT and have a different standard then there will be fun...
Of course there will be a great market opportunity for ADS-B only varios for the UK market...
Maybe after the 50 plus PPGs whoch flew the English Channel (or La Manche for the Europeans!) A week or so back, they are expecting Small Planes to replace Small Boats crossing... 🙂
Tony
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Vlad Belayev
Oct 6, 2025, 5:31:29 PMOct 6
to SoftRF_community
Good point, and also many pilots travel to Europe to fly . It would make sense to own one device which works in most places.
Plus we do already have ADS-L enabled on most of our devices, XC Tracer rolled out new firmware. SoftRF already has it to.
I tested a few times and it work with UK OGN stations.
Plus we do already have ADS-L enabled on most of our devices, XC Tracer rolled out new firmware. SoftRF already has it to.
I tested a few times and it work with UK OGN stations.
Nigel Bray
Oct 7, 2025, 6:10:39 AMOct 7
to softrf_c...@googlegroups.com
I carry FLARM (Moshe's SoftRF) and 1090 MHz ADS-B, both In and Out. Long term, I would like to add 978 MHz UAT Out and In. I licence what I can and turn everything on wherever I am. I choose the risk/consequences of transmitting when not supposed to versus the additional safety factor.
From my point of view it is a gift that the UK CAA are prepared to mandate a system for all other aircraft to carry that would avoid them crashing into us.
I think the UK CAA's hand is being forced first by an increasing amount of air traffic (commercial drones soon) in a congested airspace.
Despite the potential bungling and popular push backs, I see only ADS-B as the "one" practical interoperable solution for EC instead of railing against it and letting this drag on with several incompatible solutions.
"EASA’s philosophy for ADS-B is to encourage voluntary adoption amongst GA pilots." I think the idea that "ADS-L" (a misnomer), or other systems incompatible with ADS-B, will be seen as an alternative is misguided. I see "ADS-L" as a variant or rebrand of FLARM software using the same low power unlicenced telematics frequencies and nothing at all like ADS-B. I read all the "ADS-L" articles mentioned on EASA web pages, but fail to see any kind of endorsement other than it works as well as FLARM does.
Many of us know that ADS-B includes a re-use of age old Secondary Surveillance Radar standard that evolved over 30 years before the Mode-S variant appeared in 1983. The most common (International) ADS-B systems operate at 1090 MHz and is a variant of the Mode S standard.
There are several types of certified ADS-B data links and the newer 978 MHz link is intended to add capacity on top of the 1090 MHz frequency. This extra 978 MHz capacity appears to be handled differently in different countries.
The technical differences are explained on Wikipedia:
"In both forms of ADS-B (1090ES & 978 MHz UAT), the position report is updated once per second. The 978 MHz UAT provides the information in a single, short-duration transmission. The 1090ES system transmits two different kinds of position reports (even/odd) randomly. To decode the position unambiguously, one position report of both kinds or a reference position nearby is needed."
I expect that in time the EFIS handling of ADS-B In will surpass the performance of FLARM etc. in popular opinion, then there will be an opportunity to deprecate FLARM and other Out systems.
From my point of view it is a gift that the UK CAA are prepared to mandate a system for all other aircraft to carry that would avoid them crashing into us.
I think the UK CAA's hand is being forced first by an increasing amount of air traffic (commercial drones soon) in a congested airspace.
Despite the potential bungling and popular push backs, I see only ADS-B as the "one" practical interoperable solution for EC instead of railing against it and letting this drag on with several incompatible solutions.
"EASA’s philosophy for ADS-B is to encourage voluntary adoption amongst GA pilots." I think the idea that "ADS-L" (a misnomer), or other systems incompatible with ADS-B, will be seen as an alternative is misguided. I see "ADS-L" as a variant or rebrand of FLARM software using the same low power unlicenced telematics frequencies and nothing at all like ADS-B. I read all the "ADS-L" articles mentioned on EASA web pages, but fail to see any kind of endorsement other than it works as well as FLARM does.
Many of us know that ADS-B includes a re-use of age old Secondary Surveillance Radar standard that evolved over 30 years before the Mode-S variant appeared in 1983. The most common (International) ADS-B systems operate at 1090 MHz and is a variant of the Mode S standard.
There are several types of certified ADS-B data links and the newer 978 MHz link is intended to add capacity on top of the 1090 MHz frequency. This extra 978 MHz capacity appears to be handled differently in different countries.
The technical differences are explained on Wikipedia:
"In both forms of ADS-B (1090ES & 978 MHz UAT), the position report is updated once per second. The 978 MHz UAT provides the information in a single, short-duration transmission. The 1090ES system transmits two different kinds of position reports (even/odd) randomly. To decode the position unambiguously, one position report of both kinds or a reference position nearby is needed."
I expect that in time the EFIS handling of ADS-B In will surpass the performance of FLARM etc. in popular opinion, then there will be an opportunity to deprecate FLARM and other Out systems.
gian marco
Oct 7, 2025, 6:46:42 AMOct 7
to SoftRF_community
"Despite the potential bungling and popular push backs, I see only ADS-B as the "one" practical interoperable solution for EC instead of railing against it and letting this drag on with several incompatible solutions. etc"
sorry i completely disagree there. ADS-B is expensive and overkill. especially expensive, and then dont know what regulators will come up with next round of great ideas. people operating small, cheap airplanes usually dont keep 2-3k euro/pounds floating around just to address the latest and brightest idea from some bureaucrat who knows next to nothing about flying except airliners and bizjets. add to that a suitable GNSS source, which can be also very expensive, and the inevitable ramp tests and isntallations from certified workshops.
that means that many people will have to divert money used for fuel/maintenance/whatever to yet another piece of equipment which btw is already a horrible kludge (ADS-B was designed to use UAT and the extended squitter is dumb and expensive) and we know where that goes: less hours flown, less current pilots, more dead pilots.
ADS-L or OGN are perfectly adequate solutions, cheap light and portable, and it would make more sense to equip bigger ships with receiver for those than force thousands of recreational pilots to spend money they do not necessarily have in something they do not necessarily need.
and btw, i thought the ADS-B out issue was solved in UK by the skyecho boxes? usually Uk CAA are quite sensible but if really want to force everyone including paragliders to onboard mode S-ES boxes they are out of their mind.
just for info, in switzerland, where i fly, mode S was made compulsory several years ago. result was that half small airplanes removed the mode C and fly without any EC device, to the point where i am >donating< softrf boxes to people i have narrowly avoided midairing in G airpspace. aha, these unintended consequences.
"I expect that in time the EFIS handling of ADS-B In will surpass the performance of FLARM etc. in popular opinion, then there will be an opportunity to deprecate FLARM and other Out systems."
Nigel, trust me, most light airplanes have no EFIS, many still do not have decent GPS's, if the idea is to get rid of recreational flying to make space for big corpo drones or VIP helos, then lets outlaw recreational flying and be done with it.
and lastly, i would like to point out that nobody flying VFR needs to squawk 200watts if the purpose is to deconflict traffics.
sorry i completely disagree there. ADS-B is expensive and overkill. especially expensive, and then dont know what regulators will come up with next round of great ideas. people operating small, cheap airplanes usually dont keep 2-3k euro/pounds floating around just to address the latest and brightest idea from some bureaucrat who knows next to nothing about flying except airliners and bizjets. add to that a suitable GNSS source, which can be also very expensive, and the inevitable ramp tests and isntallations from certified workshops.
that means that many people will have to divert money used for fuel/maintenance/whatever to yet another piece of equipment which btw is already a horrible kludge (ADS-B was designed to use UAT and the extended squitter is dumb and expensive) and we know where that goes: less hours flown, less current pilots, more dead pilots.
ADS-L or OGN are perfectly adequate solutions, cheap light and portable, and it would make more sense to equip bigger ships with receiver for those than force thousands of recreational pilots to spend money they do not necessarily have in something they do not necessarily need.
and btw, i thought the ADS-B out issue was solved in UK by the skyecho boxes? usually Uk CAA are quite sensible but if really want to force everyone including paragliders to onboard mode S-ES boxes they are out of their mind.
just for info, in switzerland, where i fly, mode S was made compulsory several years ago. result was that half small airplanes removed the mode C and fly without any EC device, to the point where i am >donating< softrf boxes to people i have narrowly avoided midairing in G airpspace. aha, these unintended consequences.
"I expect that in time the EFIS handling of ADS-B In will surpass the performance of FLARM etc. in popular opinion, then there will be an opportunity to deprecate FLARM and other Out systems."
and lastly, i would like to point out that nobody flying VFR needs to squawk 200watts if the purpose is to deconflict traffics.
regulators are on average 2 decades behind the curve. time to wake up?
Message has been deleted
Nigel Bray
Oct 7, 2025, 7:31:31 AMOct 7
to softrf_c...@googlegroups.com
Dear Gian,
Sorry, I should perhaps have elaborated on what practical ADS-B means to me.
I understand that there are other views and I am fine with that, but I hope you will allow me to express my view, not to disagree with you simply to express my own.
My insight is based on seeing the viability of SkyEcho2 and studies that say:
"Per DO-260B, the lowest category of ADS-B transmitter
intended for General Aviation conforms to 70 W of transmis-
sion power. According to our analysis, there is a space for
low power ADS-B trasceiver, considering transmission power
from 10 to 20 W."
https://www.researchgate.net/publication/347042821_Low-Power_ADS-B_for_GA_Operating_in_Low_Altitude_Airspace
I agree 'that bigger ships' should be equipped with ADS-L (aka FLARM) or OGN receivers but doubt that will be imposed or form part of allowing us to access airspace that gets restricted in future.
I would have dearly loved to see or even be involved in an alternative advanced radio system for EC, but I think that opportunity passed by in the 2000's. What we have will use a little bit more power and be less efficient with spectrum than what would be possible, but it works.
PS:
I don't need to work anymore but am studying Rust, Nix, and PlatformIO like toolchains to add to my existing skillset in case I can help developing open source SoftRF like solutions in this new world.
I have 40 years in the electronics/semiconductor industry, including commercialising transceiver products, have a PPL(A), fly Hanggliders in competitions, and 300 hours and 8000km in Sailplanes.
Sorry, I should perhaps have elaborated on what practical ADS-B means to me.
I understand that there are other views and I am fine with that, but I hope you will allow me to express my view, not to disagree with you simply to express my own.
My insight is based on seeing the viability of SkyEcho2 and studies that say:
"Per DO-260B, the lowest category of ADS-B transmitter
intended for General Aviation conforms to 70 W of transmis-
sion power. According to our analysis, there is a space for
low power ADS-B trasceiver, considering transmission power
from 10 to 20 W."
https://www.researchgate.net/publication/347042821_Low-Power_ADS-B_for_GA_Operating_in_Low_Altitude_Airspace
I agree 'that bigger ships' should be equipped with ADS-L (aka FLARM) or OGN receivers but doubt that will be imposed or form part of allowing us to access airspace that gets restricted in future.
I would have dearly loved to see or even be involved in an alternative advanced radio system for EC, but I think that opportunity passed by in the 2000's. What we have will use a little bit more power and be less efficient with spectrum than what would be possible, but it works.
PS:
I don't need to work anymore but am studying Rust, Nix, and PlatformIO like toolchains to add to my existing skillset in case I can help developing open source SoftRF like solutions in this new world.
I have 40 years in the electronics/semiconductor industry, including commercialising transceiver products, have a PPL(A), fly Hanggliders in competitions, and 300 hours and 8000km in Sailplanes.
gian marco
Oct 7, 2025, 8:06:32 AMOct 7
to SoftRF_community
lower power ADS-B transponders would be already an improvement, as the high power section of xpnds is by far the most expensive part which contributes to the high price tag.
still, i think mode S-ES is a kludge, which goes on top of an already crowded area where a ridiculous amount of EC solutions exist. i didnt go into details but i am under the impression the ADS-L is more similar to OGN and most importantly an open standard unlike FLARM, and thus much more preferable.
i would have welcomed a low cost S-ES solution (skyecho2 being a possible candidate) only on account of the fact that it is, for bad or good, a standard. but after all these years, prices havent budged, and stay consistently high. and compatibility issues still exist (S-ES is extremely complex and finicky even for manufacturers)
hope this mess is in some future unwound, but surely not holding my breath.
couple weeks ago i was in Italy and met this guy in a very crowded area of north italy, where airspaces have clearly been designed by madmen. all traffic is squeezed in narrow channels below 1500ft AGL, which is madness.
i saw this guy on my stratux, he didnt see me until i overtook him. now, remove stratux and put me 100ft above him, on a low wing airplane like mine.
ok, taken with tele lenses, still, we were very close, with intersecting routes.
and btw. still most people fly without any equipment to show surrounding traffic. hope they dont expect ATC to solve conflicts in G space.
and i still have to hear any regulator talking about mandating EC in.
and i still have to hear any regulator talking about mandating EC in.
Neil Oakley
Oct 7, 2025, 8:21:17 AMOct 7
to SoftRF_community
The British Gliding Association have sent a formal response to the consultation, focussing on the technical impracticalities and costs of the proposal, and calling out the lack of technical knowledge at the CAA to even consider rolling this out. You can read it here:
On 7 Oct 2025, at 13:06, gian marco <gian...@gmail.com> wrote:
lower power ADS-B transponders would be already an improvement, as the high power section of xpnds is by far the most expensive part which contributes to the high price tag.
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VirusPilot
Oct 7, 2025, 10:07:46 AMOct 7
to SoftRF_community
Just throwing in another piece of information: what is the implementation status of the TABS mode? Only Air Avionics have a plan for their upcoming AX-1 transponder. There is not much public information available on this TABS Mode, seems that "...it saves power and reduces the 1090MHz spectrum congestion because it does not reply to interrogations from Air Traffic Control. Even though you are not visible to ATC, in TABS mode, you remain visible to TCAS and electronic conspicuity systems in other aircraft. Also, you meet the latest surveillance requirements for European uSpace (SERA.6005C)."
gian marco
Oct 7, 2025, 10:28:21 AMOct 7
to SoftRF_community
amazing. i was not even aware such system exists even though i fly and play with avionics since almost 20 years now
i am sure we needed yet another system different from the pletora of systems already in place because... donuts.
i am sure we needed yet another system different from the pletora of systems already in place because... donuts.
as an aside, im pretty sure that i read in the mode S specs that it is able to respond to selective interrogation, but then again S-ES broadcasts all the time.
hope they will hire some adult in the CAA's at some stage, and this kindergarten stuff is finally over.
another aside. it seems to me very few people have any equipment to receive ADS-B/FLARM/OGN etc.
so everyone is broadcasting, but (almost) nobody is listening. what can possibly go wrong.
Nigel Bray
Oct 7, 2025, 10:54:42 AMOct 7
to softrf_c...@googlegroups.com
TABS is not much of a thing. While I am no flag waver, the UK CAA do get some positive press here (and it explains TABS quite well):
But the Brits lowered the bar even further with EC. Instead of coming up with a spec that was still interoperable with every surveillance system under the sun, they looked ahead to what was coming, and placed their bets only on ADS-B. Oh, and they allowed it to be truly portable with no installation whatsoever. We make the most popular model called the SkyEcho.
An EC device differs from TABS in important ways that really does result in cost reduction. The spec is called CAP1391, and has since been adopted by Australia and New Zealand, and is being evaluated by a half-dozen other countries.
https://uavionix.com/blog/electronic-conspicuity-vs-tabs/
But the Brits lowered the bar even further with EC. Instead of coming up with a spec that was still interoperable with every surveillance system under the sun, they looked ahead to what was coming, and placed their bets only on ADS-B. Oh, and they allowed it to be truly portable with no installation whatsoever. We make the most popular model called the SkyEcho.
An EC device differs from TABS in important ways that really does result in cost reduction. The spec is called CAP1391, and has since been adopted by Australia and New Zealand, and is being evaluated by a half-dozen other countries.
https://uavionix.com/blog/electronic-conspicuity-vs-tabs/
gianmarco
Oct 7, 2025, 11:46:55 AMOct 7
to Nigel Bray, softrf_c...@googlegroups.com
i like skyecho2. i know a few guys who actually use it only as receiver outside the UK.
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Vlad Belayev
Oct 7, 2025, 6:40:07 PMOct 7
to SoftRF_community
Some good info here , thanks.
Indeed , the name ADS-L caused confusion in the paragliding circles with resemblance of ADS-B although its nothing like it.
I only had a small experience with ADS-B mainly using GNS5892 and porting Moshe's decoding code to ESP32-C3 board. And aware of that odd/even packet position reporting, which seems nuts.
I do think 20-30W in near GigaHertz is still a lot of power, why it needs so much?
By comparison , I have looked at many flights (by collecting data from OGN APRS stream), with SoftRF Card as a FLARM transmitter (not ideal for range PSK modulation) still provided 120-140km range to the furthest OGN station. Not just an odd packet or two, but stable signal.
I am not saying FLARM is the way to go (especially the proprietary part of it) but it has worked well in a few years. There was big adoption from the paragliding pilots, since the rebate scheme begun. That provided transmitting devices mainly. Another wave of low cost SoftRF devices like T1000E allowed to receive FLARM as well, filled that gap, so now PG pilots not only transmit, and also can see each other and sailplanes as well. If I look around on the take off, everyone has an EC device or two or three .
In my view CAA needs to put emphasis on the ground infrastructure to allow multi protocols ( but only those that able to broadcast own position ( ie fitted with good GNSS). The ground infrastructure could aggregate the received signals and re-broadcast in a different protocol that is required say for drones to operate in the same airspace. Be it ADS-B UAT or whatever.
I wanted to ask what else is out there in terms of light weight , low power ADSB-Out device except SkyEcho2?
This looks interesting and DO-260 compatible by the looks .
https://uavionix.com/uncrewed-aircraft-systems/ping20si/
Not sure about the cost, though.
Cheers.
Indeed , the name ADS-L caused confusion in the paragliding circles with resemblance of ADS-B although its nothing like it.
I only had a small experience with ADS-B mainly using GNS5892 and porting Moshe's decoding code to ESP32-C3 board. And aware of that odd/even packet position reporting, which seems nuts.
I do think 20-30W in near GigaHertz is still a lot of power, why it needs so much?
By comparison , I have looked at many flights (by collecting data from OGN APRS stream), with SoftRF Card as a FLARM transmitter (not ideal for range PSK modulation) still provided 120-140km range to the furthest OGN station. Not just an odd packet or two, but stable signal.
I am not saying FLARM is the way to go (especially the proprietary part of it) but it has worked well in a few years. There was big adoption from the paragliding pilots, since the rebate scheme begun. That provided transmitting devices mainly. Another wave of low cost SoftRF devices like T1000E allowed to receive FLARM as well, filled that gap, so now PG pilots not only transmit, and also can see each other and sailplanes as well. If I look around on the take off, everyone has an EC device or two or three .
In my view CAA needs to put emphasis on the ground infrastructure to allow multi protocols ( but only those that able to broadcast own position ( ie fitted with good GNSS). The ground infrastructure could aggregate the received signals and re-broadcast in a different protocol that is required say for drones to operate in the same airspace. Be it ADS-B UAT or whatever.
I wanted to ask what else is out there in terms of light weight , low power ADSB-Out device except SkyEcho2?
This looks interesting and DO-260 compatible by the looks .
https://uavionix.com/uncrewed-aircraft-systems/ping20si/
Not sure about the cost, though.
Cheers.
gianmarco
Oct 8, 2025, 9:35:21 AMOct 8
to Vlad Belayev, SoftRF_community
"I am not saying FLARM is the way to go (especially the proprietary part of it) but it has worked well in a few years."
my point of view, as >sorta< informed user (i dont work on code for these devices) FLARM is not the way to go because it is proprietary so users are hostage of the FLARM company and they can change the protocol and kill anyone using non-original hardware (i think it happened already)
ideally we should all use one standard because for me when flying the most important thing is to see other flying objects, but even two would be workable if the alternative to S-ES is a cheap-ish, simple solution like skyecho2 or really simple, cheap solutions like SoftRF using one ff the various protocols.
until that happens, i dont really expect any progress. Me, i still run a mode C to make ATC happy but to be honest, making ATC happy is way low in my priority list, as i fly VFR and nobody gives a damn as long as i midair with another VFR and dont disturb the important people flying IFR (IFR in europe is a luxury for the few) and i broadcast the various protocols using the usual t-beam running softrf or ogn tracker sw.
and until that happens the dreams of having a network of ground stations rebroadcasting information remains a pipe dream; besides, in flight, i dont really care about having complete maps of traffics, i only care about what is around me in the 5 to 10 miles radius,
then safesky came in and dont get me started on that....
i happen to work for a major telecom equipment manufacturer so i know as a matter of fact that data in the air is the result of leaks from the antennas and it is going to get worse not better, no subscribers to speak of in the air so for me safesky is a problem and not a solution because it creates an excuse for people to avoid installing any EC (in the general meaning of the term) equipment.
"ie fitted with good GNSS"
well if we need to install a TSO C146 complaint gps then we are back to square one costwise.
sorry for hijacking the discussion from the tech aspects of SoftRF but at the end of the day, those who use these solutions dont do it for the fun of it but to stay alive.
i still see plenty airplanes in the air which broadcast nothing, something that is hard to believe in 2025.
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