A bit over three months ago we exhibited at Sun-N-Fun with DroidEFB, one of our application partners. The show was a huge success and resulted in over 250 orders over the next month. However, one of the most common refrains we heard was, “If you had them for sale here, I would buy one!”. Well, we heard you.
We’re showing up to Oshkosh with nearly 400 dual-band FlightBox kits plus remote antenna kits, friction mounts, and remote GPS units. We’re exhibiting with Aerovie, another application partner. You can find us in Hangar C, Booth 3078.
Sun-N-Fun was a solo gig for me, which was something of a challenge. This time the whole team will be at the show, plus we have a number of volunteers who will be joining us. We’re offering a new service as part of the Oshkosh experience. The new offer – called “20 Minutes To Taxi” – is a factory assisted build: you can borrow our tools and work with one of our expert builders to get your FlightBox system assembled, tested, and ready – usually in less than 20 minutes.
We will be exhibiting all week, so if you’re able to make it up to the big show please stop in and introduce yourself.
At least once a week somebody sends me an email about an ADS-B traffic target that suddenly appeared on their EFB app, often just a hundred feet above or below, and less than half a mile behind. The reporter is never able to spot the target, which appears to doggedly follow them for a few minutes before disappearing. No, this is not a UFO or a new stealth drone. It’s just an annoying (and occasionally panic-inducing) artifact of the way ADS-B works.
If you’re being chased by ghosts, don’t worry – you’re not alone. It’s not an issue that’s specific to FlightBox or to whatever EFB app you’re using. Every ADS-B In system occasionally displays a ghost, even for those of us equipped with ADS-B Out. Here’s what appears to be happening:
You’re receiving ADS-B traffic data from the FAA ground towers. Those towers are receiving data from secondary surveillance radar. The radar data is collected at various center and terminal radar sites and sent to the towers for processing and broadcast. The software in the towers use the “hockey puck” algorithm to determine what traffic targets get broadcast.
Apparently, the delay between the time the radar site picks up a target and the time it arrives in your cockpit can vary quite a bit. Most of the time your EFB is able to determine which of the various targets it’s receiving is your aircraft (often referred to as “ownship”) which it filters out. But if the latency (time lag in delivery) is too great, the software can’t be absolutely sure if a given target is really “you” so, so it displays it – frequently with a traffic conflict warning.
Theoretically, this shouldn’t happen with aircraft that are equipped with ADS-B Out. Each Out-equipped aircraft broadcasts a unique identifier (ICAO code) which should allow both the towers and your local software to filter it out, preventing ghosts. But even the towers sometimes can’t correlate between your radar target and your position as received directly from your ADS-B Out transmissions. They fall victim to the same latency-induced issues that plague your EFB. Rather than take a chance on miss-reporting a conflict, they rebroadcast the radar data as an anonymous target which suddenly appears on your screen as a ghost.
The ghost effect appears to be worse when you’re in an area covered by multiple radars and multiple ADS-B towers. In talking with ADS-B experts, it does not sound like there’s any obvious fix for this. Lower latency links between the radar sites and the ADS-B towers can help, but even that’s not a guaranteed fix. As we get closer to 2020 and more aircraft are equipped with ADS-B Out, it should get better. Until then, don’t panic every time a mysterious traffic target appears on your screen. But don’t ignore it, either – that way lies midair ugliness.
Just a quick “thank you” to everyone who has waited patiently for the past two weeks. The vacation in France was amazing and an excellent opportunity to recharge the batteries. I’ve already begun digging out and will be shipping all of the backorders on Monday. I’ll also be going through nearly 500 email messages. It may take a day or so, but I will respond to all of them.
One other item of business: I’m extending the deadline for the AHRS Challenge. If you’re interested, you now have until July 15. Please keep in mind that the entries will be tested in the order they were received. The first entry to meet the qualifications will receive the bounty, so get your entry in as soon as you have it tested and feel confident that it will work.
Many users have contacted me over the past few days with reports of a new issue. In flight (or when near an ADS-B tower) the data flow from FlightBox periodically stops. It typically happens after 5 – 10 minutes of operations, does not cause the wifi connection to drop, and is remedied (temporarily) by a disconnect / reconnect. It only impacts systems running UAT – users with 1090-ES systems in Europe and Australia are not impacted.
After a bit of research, it turns out that our friends at the FAA recently changed weather providers and that some of the new weather data is a bit dirtier (less scrubbed for format errors) than before. Specifically, the format of certain AIRMET messages causes a fault in the Stratux software that kills the process. The issue required a very minor tweak to the code to remedy.
My family and I are going to be out from June 6 – June 17 on a long-awaited vacation. We will be in France, exploring museums and enjoying awesome food. During this time, technical support will be limited email. Phone support will not be available. Orders placed between June 5 and June 17 may be delayed.
If you need any sort of support, please contact me ASAP. If you’re hoping for a FlightBox as a Father’s Day gift, please get your order in sooner rather than later.
Thanks in advance for your patience. We’ve had five solid months of FlightBox, and we’re already gearing up for Oshkosh. This break is going to really help recharge the batteries.
I’ve had a number of users ask for an easy way to keep their FlightBox from sliding around on the glare shield. I ran a number of prototypes on the 3D printer and eventually settled on a design that is both simple and effective. It includes a broad base with a layer of sticky open cell neoprene rubber that prevents the system from moving. It’s made from the same Botaron aviation-grade plastic as the FlightBox and can be left on the glare shield for those who take their FlightBox home at the end of each flight.
I’ve ordered 100 of these from the fabricator and should have them by the time we get back from vacation. They will sell for $26.50 plus shipping. We will start offering them as an add-on to the kits as soon as they arrive.
FlightBox user Mike Albertson sent in a great suggestion for anyone who has their remote GPS receiver installed in a hard to reach location. Rather than removing the GPS every time you want to take the FlightBox out of the airplane, use an inexpensive USB pigtail cable:
Unlike the other players in the ADS-B market, we don’t have a great deal of budget for marketing. That’s a large part of what makes FlightBox so much less expensive. If you happen to have a few minutes, please do us a favor. Download and print our flyer and hang it up on the bulletin board at your airport or in your EAA chapter hangar.
For the past several weeks I’ve been receiving reports from FlightBox customers of “missing traffic” – traffic observed visually or on some other system (TIS, TCAS) but not seen on their EFB application from ADS-B. In some cases the answer was a simple misunderstanding of the way ADS-B traffic currently works, but a subset of the reports sounded suspiciously like we had a problem – somewhere. Either a bug in the Stratux software that powers FlightBox, or something going on with the ADS-B network.
Yesterday morning I decided to figure out what’s going on – or at least give it my best shot. From my own experience and from customer reports, we have no problem seeing aircraft that are equipped with ADS-B Out. What is missing is the rebroadcast secondary surveillance radar data – the copy of “everything in your hockey puck” that you’re supposed to get if you have ADS-B Out. I figured that one of the following was happening:
A) Stratux was not getting the data because of poor reception
B) Stratux was receiving but ignoring ATC traffic data due to a bug
C) Stratux was not getting the data because the FAA towers are not sending it
D) Secondary surveillance radar was not picking up the traffic
To figure out which of the above is causing the problem I put together a simple, practical test.
I own an Appareo Stratus 2 which I use as the ‘control’ in my experiments. If the Stratus has data flow from a tower but FlightBox does not, it could be failure mode A – poor reception. If both devices connect to and receive the same data from the towers, that essentially rules out condition A. If the Stratus receives and displays traffic that is not visible to the FlightBox, the root cause might be failure mode B – a bug in the Stratux code. But if both devices display the same traffic, that rules out condition B. Failure modes C and D take a bit more effort to test.
My 1976 Grumman Tiger is equipped with FreeFlight Systems RANGR Lite UAT transmitter, and I regularly request status reports from the FAA. As of the last test (a few months ago) I was 100% ADS-B Out compliant. In other words, I should absolutely trigger the towers and receive a “puck” of ATC radar data for aircraft in my vicinity. To test if the ATC radar is making its way to the ADS-B network, I enlisted the help of my friend Larry. Larry flies an Arion Esqual – a precursor to the popular Lightning homebuilt – which has a standard Mode C transponder but no ADS-B Out. His job was to fly in relatively close formation with me to present a controlled traffic target.
Yesterday morning Larry and I took off from Roosterville (our home airport). I had two iPads running ForeFlight – one connected to the FlightBox and the other connected to the Stratus 2. I took off first and climbed to 1000’ AGL where both systems showed solid connection to two ADS-B towers. When Larry took off, I kept an eye on the iPads looking for him to appear on ForeFlight.
We flew south from Roosterville towards Liberty Landing. I let Larry stay roughly a half mile ahead and 200 feet above me. He did not appear on either iPad at 2,000′ MSL (~1100′ AGL). After roughly five minutes at 2,000′, I asked him to climb up to 3,000′. At roughly 2,500′ MSL, he appeared as an ADS-B traffic target 100’ above me an less than a mile head. Ok, it appeared to be working as expected.
To figure out the “bottom” – the lowest altitude at which it worked – I asked him to descend. He dropped off the screen at roughly 2,200′ MSL. We made a turn out towards the east and decided to see where he re-appeared. He began a steady climb that eventually topped out at 3,500′ MSL, without reappearing on either device. A quick check of the Weather tab showed that FlightBox was continuing to receive ADS-B data from the towers. Both the Stratus and the FlightBox continued to show both 1090-ES and UAT targets, but all appeared to be direct.
We flew for another 30 minutes at various altitudes. Larry only appeared again briefly, at 3,900′ MSL. On the off chance that we were too close – that ATC saw one target instead of two – we diverged to at least a mile separation. No joy. We contacted Kansas City approach to make sure that we being seen by radar. They had us 5-by-5 in exactly the right spot. Larry was at 3,900′ and I was below him at 3,200′. That would seem to eliminate the admittedly far-fetched failure mode D.
To review the facts:
Later in the day I went back up alone and spent some time in the airspace below the Kansas City class B directly along the approach path for runway 18 at MCI. I was within 10 miles of the ADS-B tower at Dearborn, Missouri and maintained a solid connection to it. I spent twenty minutes or so visually observing airliners arriving and departing above me. None of them appeared on either ADS-B system.
All of this seems to indicate that the cause of the missing traffic is failure mode C – the ADS-B network simply is not sending the data. The next question is, of course, why? My ADS-B Out transmitter was running. I should have had a puck that included Larry and the MCI traffic. Why wasn’t I able to see either?
Hard to say. It might be that the only radar that feeds into the ADS-B system is ARTCC (“Center”) and the altitude range we tested (2,000′ – 4,000’ MSL) was below the visibility “cone” for their radar. But they did have Larry as low as 2,500′ MSL for a while. It seems more likely that whatever gateway feeds ATC secondary surveillance radar data into the ADS-B network is flaky. Or that the software in the towers that calculate the “pucks” has a problem.
Whatever the cause, never assume that ADS-B provides a complete picture of traffic – even if you’re equipped with ADS-B Out. We’re still very much in a “see and avoid” world, and probably will be until at least 2020.
If you have two ADS-B In systems and a friend who’s willing to play along, please try to replicate my experiment. I would love to have enough evidence to take this to the FAA and get some kind of response.
As most of you know, we’re working on a hardware add-on for FlightBox that will include AHRS – the sensors and software necessary to drive a virtual attitude indicator or provide attitude data to a synthetic vision system. We’ve made good progress on this. Our hardware engineer has selected components and is currently working on the board design. What may not seem obvious is that the hardware is the easy part. Software is where the real challenge begins.
If you’ve ever played with a motion-sensitive game on a smartphone that may seem counterintuitive. A $100 Android phone can easily determine attitude, right? Well, yes – in some situations. It’s easy to accurately determine attitude when standing still or moving at a steady pace. It’s far more complicated when you take into account fixed-wing flight dynamics.
There are several products on the market today that claim to provide backup attitude, and they appear to do – as long as you’re flying straight and level. Drop into a 30° bank and the screen will show it – for a few seconds. But hold the turn for a few seconds and you’ll notice something disturbing: the display starts to level out. After another few seconds the display shows straight and level again – while you’re still turning. Huh?
It turns out that without some very clever software, the hardware sensors fall victim to the same effect that makes your inner ear such a bad attitude indicator – centrifugal force. In straight and level flight, your ear and the inertial sensors in the phone both detect one acceleration, that of gravity. When you’re turning, you are subject to two accelerations: gravity and the “false gravity” of centrifugal force. In VFR your brain compensates for this using your view of the horizon to override what your inner ear thinks is happening. To accurately display attitude the AHRS system needs something similar – a means of determining what sensory inputs it should ignore.
Many, perhaps most, off the shelf IMUs (inertial measurement units) – the core sensors of an AHRS – are built for use in cell phones or quadcopter drones. Neither of these are subjected to fixed wing flight dynamics. To build a real AHRS, the data from the IMU must be filtered to eliminate noise and must have the inertial (centrifugal) vector factored out of the readings. This is the real challenge of AHRS. Without this, you don’t have an AHRS – you have a toy.
Fortunately, there are people out there who are very good at the kinds of mathematics required and who could create a set of algorithms that combines data from an IMU and a GPS to provide a realistic attitude solution. Unfortunately, I am not one of those people. Thus the Open Source AHRS challenge:
Open Flight Solutions in partnership with Aerovie, Hilton Software, and DroidEFB is offering a bounty of $4,000 to the first developer or team of developers who can provide an open source AHRS implementation that can successfully return an accurate and timely orientation based on raw IMU (3 axis accelerometer, magnetometer, and gyroscope) and GPS data. Please see “The Rules” for details on the requirements and terms.
If you are a developer and you think you might be able to solve this, please jump in. If you know any developers who might be interested, please pass this along. We’re know that this problem can be solved in a way that makes GA safer and more affordable.
UPDATE: We’ve decided to extend the challenge through July 15, 2016.
This isn’t my first entrepreneurial rodeo, but it’s been a while. I’ve spent the past several weeks re-learning several lessons. The first of these is that platform changes are never as easy as you expect. We recently switched from using the Raspberry Pi 2 to the new Raspberry Pi 3. In theory the change should have been quite simple and a small net positive for both users and Open Flight. I ordered two of them the day they were released and put more than 25 flight hours on them before we made the switch. But – as anyone in the IT field knows – just because something works perfectly on one system (or two) is no guarantee that it will do the same on all systems – even theoretically identical semi-embedded devices like the Raspberry Pi. I re-learned the hard way that a larger sample is mandatory.
At the end of April we sent out the first 75 kits based on the Pi 3. We had approximately 25 of them mysteriously fail – no wifi. After a weekend of research it turned out to be an incredibly subtle change in the shell script command interpreter on the new Linux operating system. A script that had been working fine for months on the Pi 2 failed to work correctly on some of the new Pi 3s. A somewhat longer power cable that we shipped with the Pi 3 kits exacerbated the problem significantly. I spent the next several days writing and testing a new script. We tested it on 10 different Pi 3s from two lots. We re-imaged 250 SD cards, built up over 50 “recovery packs”, and shipped them out to anyone who had problems Pi 3. A week later we had almost everyone up and running. (If you’re not, please contact me ASAP.)
The lesson is to never, ever take for granted that something works. If we make another platform change in the future, I will round up as many beta testers as I did for the original FlightBox launch early in the year. We had close to a dozen people test-flying the first build, and we had very little in the way of trouble with it. Lesson learned. Sincere apologies to anyone who was bit by this bug.
For everyone who’s been waiting for a remote GPS option, the wait is over. We have 100 remote GPS units in stock and more on order. You can order them here. The list price is $35, but I am offering a one-time $10 discount to all existing FlightBox owners (anyone who has completed an order prior to to today). Please email me for your personal discount code. Before you order, please note that we’re working on a complete “remote kit” that includes the GPS as well as cables and a suction cup window mount for the ADS-B antennas. If you want the full remote solution, wait another few weeks you can save yourself a bit on shipping. The $10 discount will apply to that as well.
The remote GPS will require a bit of minor surgery on your FlightBox case. You may have noticed the U-shaped partial cut at the end of the box near the USB risers. To use the remote GPS you will need to cut out the “U” to make room for the USB plug from the GPS. I hope to publish a video showing how this is done in the next few days. The plastic is thin and it is quite simple to make the cut with an Xacto knife.
We’ve made the decision to phase out the VK-172 GPS module that we’ve been shipping since we launched. When they work, the VK-172s are great little GPSs, but we’ve had enough marginal performers that it makes more sense to remove it and instead offer an optional product that has top-notch quality, stateside technical support, and an RMA program. (Sending products back to China is… problematic.) We’re dropping the price of the dual band kit from $250 to $240. The remote GPS will be available as a $35 add-on, which makes it a bit more expensive than it is today – but only if you want or need the GPS feature.
(Note that any outstanding orders placed prior to today will go out with the internal VK-172. Anyone with an outstanding order qualifies for the $10 discount on the remote GPS.)
At the same time we are adding an option for high gain antennas. These are 978 MHz and 1090 MHz tuned antennas that are 1/2 wave, rather than the 1/4 wave of the stock antennas. They significantly increase the receiving power (gain) of the system, which can be useful in areas with limited ADS-B coverage. They’re rather large (about twice the size of the stock antennas) but well worth it if you’re a long way from towers and need to boost the signal. They will add $10 to the cost of a kit.
The arrangement I’ve worked out with the manufacturer only allows us to sell them as part of a kit, but they are available on Amazon. (As of this moment they are out of stock. The seller assures me that more are on the way.)
I probably get five emails a week asking about the state of the AHRS project, so here’s an update. We’re making good progress. We have the initial hardware design complete and hope to get our first round of prototypes later this month. We are still working towards Oshkosh as a launch target. I will have a blog post dedicated exclusively to AHRS next week, so please check back.
Last week was something of a blurr. On Sunday I loaded up the Tiger with everything I needed for an exhibit (table, banner, demo FlightBoxes, tablet stands, tablets, etc.) and flew from Liberty, Missouri to Thomasville, Georgia. I spent the night there with some old friends (thanks, Ryan and Gina!) then got up on Monday morning and flew on to Lakeland for Sun-N-Fun 2016.
If you’ve never done an arrival into a busy show like SnF, I highly recommend it – it’s both challenging and a lot of fun. I was really glad to have ADS-B traffic on the way in, as the airspace became rather crowded as I approached the rendezvous point near Lake Parker. Everything went exactly as described in the NOTAM – everyone queued up and flew west to I-4, then followed it south-west until we crossed a golf course. We turned south and entered the pattern mid-field. The controllers called our entry into downwind, base, and final from that point using our aircraft type and color. Huge kudos to the controllers – that has to be a stressful job, and they all handled it with grace and humor.
I’ve been to Oshkosh several times, but this was my first time at Sun-N-Fun. It’s not as big, but that hardly tells you anything as Oshkosh is huge. I parked the Tiger in General Parking, picked up my rental car, and hauled my gear over to the exhibit area. I partnered with Avilution for SnF. They make Droid EFB, an excellent flight planning and navigation app build for Android tablets and phones (it works brilliantly with FlightBox). They also are in the process of rolling out XFS, or eXtensible Flight System – a new concept in avionics based on the idea that the hardware should be generic and the actual functionality should be entirely driven by software. Big thanks to Mark, Jacek, and the rest of the Avilution team for sharing space and helping cover the booth when I stepped out.
Most of the week was spent talking FlightBox with hundreds of pilots. We had a system up and running, receiving data from all the ADS-B out equipped aircraft around Lakeland and from the ground tower located across the field. That fed traffic and weather to two tablets: a Samsung Galaxy Tab S2 running Droid EFB and Avare and an iPad Mini 4 running ForeFlight* and Aerovie Reports. I used a second FlightBox kit to show potential customers just how easy it is to assemble. I think I must have put that kit together 200 times, and every time somebody in the group gathered around the table said, “Wow, that really is easy.”
One of the most interesting things to come out of Sun-N-Fun was the announcement that Dynon Avionics and EAA had collaborated to receive STC approval for Dynon’s D10A mini-EFIS. This is huge news because it’s the first time that a product built for the experimental market has been approved for use in certificated aircraft without going through the usual TSO process. The AML currently covers the Cessna 172 and 150 families as well as the Piper PA-28 and PA-38 lines. Additional aircraft will be added to the AML in the near future. I’m friends with several of the people at Dynon and immediately volunteered the Tiger as a test platform. (I suspect that many other people did the same.)
Dynon and EAA made use of a new ASTM Standard: 3153-15 Verification of Avionics Systems. I’m extremely proud to mention that I served on the task group that developed that standard. Where the TSO process makes use of a very complicated, expensive, and frankly rather hand-wavy approach to software safety called DO-178, the new ASTM standard follows best practices used by manufacturers serving the experimental and LSA markets. Where DO-178 is several hundred pages of process, ASTM-3153-15 is two pages long and uses a simple, practical procedure to identify critical functions, specify tests, execute those tests, and document the results. The cost to the manufacturer is a fraction of what it would take for TSO approval, with a level of safety which is appropriate for a light, personal aircraft.
I really can’t overstate how important this is. It’s a small step but it may be the first of many that will ultimately allow owners of legacy aircraft to update with safety-enhancing technology. The D10A is officially seen as an attitude indicator, not an EFIS – you can’t remove any of your other instruments. Only the attitude is “primary” with the many other features being advisory. Understood. I’ll take it.
We’ve had a number of users contact us looking for an easy way to remote-mount the GPS. The radio noise from the wifi transceiver, the brushless motor on the fan, and the Raspberry Pi all impact the sensitivity of the GPS. Add to that the radio noise from various aircraft systems and you can wind up with only modest performance. While we would never recommend using the FlightBox GPS as a primary navigation source (that requires FAA testing and certification) we are considering offering an option that would allow you to remote-mount a somewhat more sensitive GPS for greater accuracy.
The FlightBox case is designed to allow you to cut out the U-shaped notch at the end and insert a USB extension cord. This can be used to remote the existing GPS, but you then need to build some kind of housing for it. We’ve done some research and it looks like we may be able to offer a somewhat more sensitive GPS that comes with a 4′ USB cable. This would give you the flexibility to locate the receiver “puck” away from the FlightBox. It would also make it much easier for anyone who wants to blind-mount their FlightBox by remoting the standard antennas or by using a belly-mounted transponder or DME antenna.
If you’re interested in a remote GPS or antenna option, please send me an email. If I get enough interest, I will place an order and write up some instructions.
Low Power Blues: Over the past few weeks I’ve had a number of people call up with systems that appear to be working but which do not establish a “FlightBox-XXXXX” wifi network. In every case the cause has been weak power supplies: either a 1 amp wall charger or even the low-power USB port on a laptop. PLEASE don’t try to run FlightBox off of any power source – battery or adapter – that is not rated for at least 2 amps. It will not work!
Floppy Antenna: I’ve also received a number of calls regarding the 978 MHz antenna flopping over. This happens when you can’t screw it on tight enough for the SMA connectors to properly mate. You need to either tighten up the nut on the SMA bulkhead connector. If that doesn’t fix it (and don’t go crazy and strip the nut or the connector) you may need to remove the lock washer. That will give you enough thread on the SMA barrel to properly tighten up the antenna.
This Fan Sucks: When I wrote up the instruction guide, I failed to mention that the fan needs to blow out through the top. I covered it on the video, so if you watched that, all is probably well. If you didn’t, there’s some chance that your fan is sucking in air from on top of the box and blowing it out the vents in the side. That’s backwards. You want to mount the fan so that the sticker is facing the plastic top and not visible. You’ll find arrow marks molded into the plastic showing the direction of spin and air motion. Air should go out through the top!
New FAQ and Troubleshooting Guide: We’ve compiled some of the most common questions about FlightBox into an FAQ (Frequently Asked Question) page. We’ve compiled many of the most common issues users experience into a Troubleshooting Guide page. If you have questions or troubles, take a look at either / both for answer. If you don’t find what you need there, give us a call or drop us an email.
If you like what FlightBox does for you and think other pilots at your airport might want give it a try, please download this flyer, print it, and post it on the bulletin board. We truly appreciate your help in making aviation safer and more affordable.
Since we’ve started shipping FlightBox kits, I figured it was time to put up some instructions. The goal has always been to keep the process as simple and quick as possible. I’ve timed myself, and I can assemble a Dual Band FlightBox in about 4 minutes. A friend who agreed to act as a guinea pig took about 15 minutes, and he was using only the printed Assembly Guide. Based on his feedback and input from a number of other helpful reviewers, I tweaked the guide to make a few steps even clearer.
We also now have an Assembly Tutorial video that should help those who prefer to learn visually:
It’s permanent home is here: https://www.openflightsolutions.com/flightbox/tutorial/
Last Friday evening I had the honor and privilege of giving a presentation on ADS-B, Stratux, and FlightBox at VAA Chapter 16 in Gardner Kansas. The talk covered all the basics of ADS-B In and Out, as well as an introduction to Stratux and FlightBox. There were something like 30 – 40 people at the meeting, and they seemed to like the presentation, so I’ve decided to share a PDF of it for anyone who’s interested. They devoted over two hours of their weekend, asked a lot of good questions that I hope to wrap up into an FAQ, and in general were great hosts and a wonderful audience. (I ended up joining the chapter – $20 well spent.)
ADS-B is confusing: two system (UAT / 1090) and two function (out / in). I hope this helps clear up some of the questions. Please let me know if you would like a live presentation – I really enjoy meeting people and geeking out on all-things aviation.