ADS-B receivers

DouglasVB

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Thought I'd start a thread on ADS-B receivers. It's dealing with radios but only the receiving end so I think it almost fits this sub-forum 😁

I've got a dual ADS-B receiver setup at my parents place in the mountains of California. The receivers fill in a small coverage gap for the major ADS-B aggregator services for low-flying aircraft (mainly for fire fighting, and search and rescue). The other ADS-B receivers in the area are blocked by ridges and mountains so their place is useful and unique.

The receiver is based on a Raspberry Pi 4b 4gb model. It has a 32gb microSD card installed. I'm running two Flight Aware Pro Sticks at 1090 MHz (the primary frequency) and 978 MHz (sometimes used by light planes in the USA). I have two Flight Aware outdoor antennas -- one tuned for 1090 MHz and one tuned for 978 MHz. I have a genuine Raspberry Pi power supply designed for the 4b that can put out the required amperage (not all power supplies are created the same). I've got two coaxial cables to go from in the garage where the Raspberry Pi is located up through the attic and out to the peak of the roof where the two antennas are located.

I had been running a PiJuice Hat (a baby uninterruptable power supply) for about six months to prevent cooking the microSD card during a power outage and recovery (I cooked a couple cards before I realized what was going on -- Raspberry Pis don't always gracefully shutdown and recover from a power outage) but I recently ditched the PiJuice and installed the cheapest lead acid battery-based UPS on the market. My parents have a Generac backup generator with automated transfer switch running off a 500 gallon propane tank so unless the outage lasts longer than two weeks and no one is there to service the generator (it needs its oil topped off every two weeks of running), the UPS should be fine. The reason I got rid of the PiJuice is because the little cell phone battery it came with started bulging in a very angry way. I do not want a spicy pillow to detonate in my parents garage!

At one point I was running some Flight Aware brand bandpass filters but I realized that my parents live in such a RF quiet area that the receivers get many more ADS-B packets and can "see" much farther away without the filters in place. If I were in a dense urban area, I would probably be running the filters.

Antennas on the roof


Photo above is from when I mounted the antennas on the roof. I'm planning to redo this at some point. But they have held up through about six feet of snow sitting on the roof without complaint.

1630280599371.png


Photo above shows what the receivers can "see" from planes sending ADS-B packets transiting through. This is a pretty good match for the mountains and ridges that block sight lines in the area. The couple of little wedges of no ADS-B packet reception match up pretty well with where there are a couple of close trees. It would be much better if the antennas were on top of a tower with an uninterrupted line of sight but that's not possible with where my parents house is located.

I'm currently feeding ADS-B Exchange (free, open-source, nothing blocked or filtered), Flight Aware (the "big boy" in the ADS-B aggregator service market), Flight Radar 24, and Radar Box. The world of ADS-B aggregator services seems pretty wild based on my few interactions with each of these organizations. Flight Aware, Flight Radar, and Radar Box all seem to make their money based on subscription services including blocking certain transponders from their websites (rich people, dictators, and militaries can make their planes disappear on these services for a price) and expanded access to their data (historical flight tracking, longer before the session times out, etc.). ADS-B Exchange I think makes their money selling their unfiltered data to commercial organizations. The three regular commercial companies have pretty decent customer service and support. ADS-B Exchange has some very paranoid people who run their Twitter account.

The Raspberry Pi is running a vanilla copy of Raspbian (based on Debian which is a Linux operating system) with the 1090dump and 978dump packages installed. Then I installed each of the four ADS-B aggregator services' software packages that listen to the 1090dump and 978dump outputs and send that on to the aggregator servers. The overall amount of data sent out to the internet is basically negligible.

If you want to have an ADS-B receiver setup at your house, you can get everything to get up and running for under $200. For a "top of the line" setup with dual receivers for 1090MHz and 978MHz you're talking more like $300-350.

It does take a certain amount of familiarity with computers and command lines but there are a *ton* of really good guides online to get you 100% up and running.

The hardest part of the whole installation was getting the coax cables up through the attic and installing the antennas on the roof. From start to finish, it took me a weekend to assembly the Raspberry Pi, get the software installed, and install the antennas.

The reason I ended up installing my ADS-B receiver was after last year's Creek Fire and not knowing what the fire fighting aircraft were doing near my parents place. While it's true that the Air National Guard often runs with their ADS-B transmitters off (I guess they're not required to run them), most of the firefighting aircraft do keep their transmitters turned on. My dad enjoys being able to know which helicopters are buzzing by and where they are going and when they have to evacuate for the next big fire, they should have some extra peace of mind knowing where the aircraft are focusing their attention.

1630281791758.png


Above you can see all the planes and helicopters working a fire in the southern Sierra Nevada. It's a great way to see what's going on in the sky.

Is anyone else running an ADS-B receiver?
 

3rdGen4R

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Thought I'd start a thread on ADS-B receivers. It's dealing with radios but only the receiving end so I think it almost fits this sub-forum 😁

I've got a dual ADS-B receiver setup at my parents place in the mountains of California. The receivers fill in a small coverage gap for the major ADS-B aggregator services for low-flying aircraft (mainly for fire fighting, and search and rescue). The other ADS-B receivers in the area are blocked by ridges and mountains so their place is useful and unique.

The receiver is based on a Raspberry Pi 4b 4gb model. It has a 32gb microSD card installed. I'm running two Flight Aware Pro Sticks at 1090 MHz (the primary frequency) and 978 MHz (sometimes used by light planes in the USA). I have two Flight Aware outdoor antennas -- one tuned for 1090 MHz and one tuned for 978 MHz. I have a genuine Raspberry Pi power supply designed for the 4b that can put out the required amperage (not all power supplies are created the same). I've got two coaxial cables to go from in the garage where the Raspberry Pi is located up through the attic and out to the peak of the roof where the two antennas are located.

I had been running a PiJuice Hat (a baby uninterruptable power supply) for about six months to prevent cooking the microSD card during a power outage and recovery (I cooked a couple cards before I realized what was going on -- Raspberry Pis don't always gracefully shutdown and recover from a power outage) but I recently ditched the PiJuice and installed the cheapest lead acid battery-based UPS on the market. My parents have a Generac backup generator with automated transfer switch running off a 500 gallon propane tank so unless the outage lasts longer than two weeks and no one is there to service the generator (it needs its oil topped off every two weeks of running), the UPS should be fine. The reason I got rid of the PiJuice is because the little cell phone battery it came with started bulging in a very angry way. I do not want a spicy pillow to detonate in my parents garage!

At one point I was running some Flight Aware brand bandpass filters but I realized that my parents live in such a RF quiet area that the receivers get many more ADS-B packets and can "see" much farther away without the filters in place. If I were in a dense urban area, I would probably be running the filters.

View attachment 98006

Photo above is from when I mounted the antennas on the roof. I'm planning to redo this at some point. But they have held up through about six feet of snow sitting on the roof without complaint.

View attachment 98007

Photo above shows what the receivers can "see" from planes sending ADS-B packets transiting through. This is a pretty good match for the mountains and ridges that block sight lines in the area. The couple of little wedges of no ADS-B packet reception match up pretty well with where there are a couple of close trees. It would be much better if the antennas were on top of a tower with an uninterrupted line of sight but that's not possible with where my parents house is located.

I'm currently feeding ADS-B Exchange (free, open-source, nothing blocked or filtered), Flight Aware (the "big boy" in the ADS-B aggregator service market), Flight Radar 24, and Radar Box. The world of ADS-B aggregator services seems pretty wild based on my few interactions with each of these organizations. Flight Aware, Flight Radar, and Radar Box all seem to make their money based on subscription services including blocking certain transponders from their websites (rich people, dictators, and militaries can make their planes disappear on these services for a price) and expanded access to their data (historical flight tracking, longer before the session times out, etc.). ADS-B Exchange I think makes their money selling their unfiltered data to commercial organizations. The three regular commercial companies have pretty decent customer service and support. ADS-B Exchange has some very paranoid people who run their Twitter account.

The Raspberry Pi is running a vanilla copy of Raspbian (based on Debian which is a Linux operating system) with the 1090dump and 978dump packages installed. Then I installed each of the four ADS-B aggregator services' software packages that listen to the 1090dump and 978dump outputs and send that on to the aggregator servers. The overall amount of data sent out to the internet is basically negligible.

If you want to have an ADS-B receiver setup at your house, you can get everything to get up and running for under $200. For a "top of the line" setup with dual receivers for 1090MHz and 978MHz you're talking more like $300-350.

It does take a certain amount of familiarity with computers and command lines but there are a *ton* of really good guides online to get you 100% up and running.

The hardest part of the whole installation was getting the coax cables up through the attic and installing the antennas on the roof. From start to finish, it took me a weekend to assembly the Raspberry Pi, get the software installed, and install the antennas.

The reason I ended up installing my ADS-B receiver was after last year's Creek Fire and not knowing what the fire fighting aircraft were doing near my parents place. While it's true that the Air National Guard often runs with their ADS-B transmitters off (I guess they're not required to run them), most of the firefighting aircraft do keep their transmitters turned on. My dad enjoys being able to know which helicopters are buzzing by and where they are going and when they have to evacuate for the next big fire, they should have some extra peace of mind knowing where the aircraft are focusing their attention.

View attachment 98008

Above you can see all the planes and helicopters working a fire in the southern Sierra Nevada. It's a great way to see what's going on in the sky.

Is anyone else running an ADS-B receiver?

ADS-B is super powerful. Whats a bummer for you is that you don’t get anything besides air traffic, but in reality, as a pilot I use it for everything information wise in the cockpit besides the required weather briefing at the airport I plan to land at. ADS-B will report lightning (FIS-B), forecast weather, radar, TFRs, and other data. Because you don’t get those stations because you are on the ground it’s kind of a bummer because if you did you would bring it with you every time you were in the outdoors.

To be honest, you really can get a top of the line setup for $200 and you can fly with it and broadcast your airplanes tail number. Piaware makes some good receivers. Check them out if you get a chance.

Does flightaware not give you the same data in regards to what you get for the ADS-B device?

R,



Phillip
 

DouglasVB

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To be honest, you really can get a top of the line setup for $200 and you can fly with it and broadcast your airplanes tail number. Piaware makes some good receivers. Check them out if you get a chance.

Yup $200 is about what it takes to get an ADS-B receiver setup on the ground that will feed all the various ADS-B aggregators. I'm running the Flight Aware (they make Pi Aware) USB stick receivers but I assembled all the parts myself rather than getting a pre-built system.

Unless I win the lottery, there aren't any planes in my future so no need for the transmitter part that they use on planes :)

Does flightaware not give you the same data in regards to what you get for the ADS-B device?
So I'm feeding four different ADS-B aggregators using 1090dump and 978dump. ADS-B Exchange doesn't filter anything like Flight Aware, Flight Radar 24, and Radar Box do (they generally filter military flights and tail numbers of people who pay $$$ to not be reported on their services). But ADS-B Exchange doesn't have quite as good of coverage as the others.

Whats a bummer for you is that you don’t get anything besides air traffic, but in reality, as a pilot I use it for everything information wise in the cockpit besides the required weather briefing at the airport I plan to land at. ADS-B will report lightning (FIS-B), forecast weather, radar, TFRs, and other data. Because you don’t get those stations because you are on the ground it’s kind of a bummer because if you did you would bring it with you every time you were in the outdoors.
I believe that those info streams are available if I was line of sight to one of the FAA transmitters. When I did some tests at my house in Monterey with line of sight to the airport, I got all of those data packets. I think they're called TIS-B as a group? While there is a USFS heliport for firefighting near my parents place, there aren't any transmitters there.

But with the ADS-B aggregators, they suck up all the data needed from the thousands of receivers that send their data in. So it's not just my receiver but a whole bunch of receivers. Here's what it looks like right now with the planes coming into and out of the SF Bay area:

1630298391742.png


And here's the nearby stations to my parents place that are feeding Flight Aware.

1630298493764.png


Lots of folks just in their area are feeding. The more that feed, the better the tracking data and the more places that get filled in on the coverage map. One area that I see having trouble is the canyons in the mountains -- there aren't any houses in there so no one has feeders. So when there's a helicopter working a fire in a canyon, it's rare to get more than a few packets once in a while to show something's going on there. There are some satellites now selling a service for ADS-B tracking over oceans but I don't think any satellites are currently feeding any of the commercial ADS-B aggregators. Maybe someday there'll be some amateur radio satellites with ADS-B receivers aboard.
 

DaveInDenver

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To be honest, you really can get a top of the line setup for $200
It doesn't have to cost $200 but it could add up if you have to start from zero and want a stand-alone system where you'd need a RPi and everything. If someone's just interested in tinkering using a PC they already have all you strictly need to start is a generic R820T SDR dongle (around $20) and an antenna, which you can make yourself.

https://www.rtl-sdr.com/adsb-aircraft-radar-with-rtl-sdr/

You don't need a dedicated Raspberry for this even if you want to stream it to FlightAware. It just ties up your computer if you do it 24/7/365 though. But I use an ancient 32-bit laptop (Core Duo even!) running Ubuntu for stuff like this. Those are cheaper than RPis, usually people are happy to give them to you instead of trying to recycle them. And they have a built-in display, keyboard and mouse already. Although it's getting to the point where you need 64-bits to do anything. SDRtrunk won't run on low level hardware as it's doing the AMBE vocoding in software, along with trunking and DSP, so a RPi 4 (e.g. 64-bit ARM) would be minimum.

If you're really trying to make a decent receiving station a band pass filter around 1090MHz is very helpful (these dongles can hear their own USB ports and are really prone to close-in overload (e.g. strong local stations, nearby computers, your microwave oven) and intermod, so weak signals are definitely not their strong suit). It always better to have an external antenna mounted somewhere and a run of coax, which might then require an LNA depending on the coax you use. Using decent coax, RG-8, it's only 5 dB per 100 feet at 1 GHz, so maybe not if you have a little bit of antenna gain to compensate.

If you've built a decent antenna and give the radio a fighting chance with some filtering you probably don't need anything more. You have to be careful with adding LNAs not to saturate the front ends of these sticks. With a good antenna they almost never need more help and too much gain just causes the AGC to roll back anyway. These dongles were originally designed to receive broadcast TV with a coat hanger hung on them inside a brick apartment building afterall.

One thing to be very careful about with these dongles with external antennas is static. They are *very* easily damaged unless you bleed static from your antenna. Not to speak of during thunderstorms... But just the breeze causes static to build on antennas and you need to have a way to ground them. That's almost always the first thing that is eliminated when reducing the size and cost of a radio.

The Rafael R820T has a built-in LNA already that tops at 49 dB of gain. The tuner has a kind of high noise floor (about 3.5 dB at max gain), so if you spend some money one a *good* LNA at the antenna you can certainly improve the overall performance but only if you use an LNA that's better quality than the dongle itself, which is unlikely until you spend perhaps $75 or more. And even then the limitation is the dongle itself. You can't expect to pay $35 for an SDR and get high quality. They are very handy (I have several, I like the RTL-SDR v3 personally) but they are not substitutes for real radios.
 
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Inukshuk

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I figured if you all are talking about it, maybe it matters. But not really for 99% of us. As I learnde me at

"ADS-B" for dummies!

What is ADS-B?
At heart, ADS-B is really just a new way to manage air traffic. As such, it will eventually replace radar as Air Traffic Control's (ATC) primary tool for separating aircraft. It's different from radar in that it does not depend on controllers in a central location watching radar scopes. Instead, aircraft self-report their GPS position in a networked environment, so pilots can see the entire air traffic picture around them. There is also the added benefit of datalink weather and traffic available through ADS-B.

now, where is that unsubscribe button .... :)
 

DouglasVB

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If you're really trying to make a decent receiving station a band pass filter around 1090MHz is very helpful (these dongles can hear their own USB ports and are really prone to close-in overload (e.g. strong local stations, nearby computers, your microwave oven) and intermod, so weak signals are definitely not their strong suit).

Through trial and error I found with my setup that the filters were great in the city for getting more packets but were worse in the mountains in a very RF quiet area.

One thing to be very careful about with these dongles with external antennas is static. They are *very* easily damaged unless you bleed static from your antenna. Not to speak of during thunderstorms... But just the breeze causes static to build on antennas and you need to have a way to ground them. That's almost always the first thing that is eliminated when reducing the size and cost of a radio.

What are you doing to bleed the static off the antennas and make the setup safe in a lightning storm?

now, where is that unsubscribe button .... :)

Haha too late now you're sucked in!!!
 

DaveInDenver

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What are you doing to bleed the static off the antennas and make the setup safe in a lightning storm?
There's various ways to protect and ground your stations, but most people use some type of block, usually with a discharge tube or slug. The main names I know of are PolyPhaser, Alpha Delta, Morgan Systems and Array Solutions.

https://www.polyphaser.com/search?Category=RF+Surge+Protectors&sort=y&view_type=grid

https://www.arraysolutions.com/surge-and-rf-protection

https://www.surgestop.com/

https://www.alphadeltaradio.com/

I should note that per NEC Article 810 receiving and transmitting antennas are required to be grounded and lightning/surge protected. So this plus doing an RF exposure analysis is something every one with a home station should be doing.
 
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DanS

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ADS-B is super powerful. Whats a bummer for you is that you don’t get anything besides air traffic, but in reality, as a pilot I use it for everything information wise in the cockpit besides the required weather briefing at the airport I plan to land at. ADS-B will report lightning (FIS-B), forecast weather, radar, TFRs, and other data.
Hah! Our ADS-B doesn't do any of that. Some of that information I can access through ACARS, but not much more than METARs and TAFs. Everything else relies upon our dispatcher to forward to us.

We don't even get traffic info from ADS-B, even though we are obviously transmitting it and have a full TCAS II setup (which is why we don't have any traffic info from ADS-B).

But now that this thread is up... I'm kind of surprised how many things fly over my place that don't show up on any of the aggregators. Guess this is why. I might need to put up my own antennae just because. Even crossing the pond we get full ADS-B coverage, but I'm not entirely sure where from. Guess I never though about it that much. But the discussion of the range of ADS-B in RF quiet areas probably explain why someone sees us at 30West.

Fascinating.

Dan
 

DouglasVB

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I figured for sure you'd have an ADS-B setup at home already, Dan!

One thing we've noticed is a lot of low flying air traffic near my parents with their transponders turned off. Some of it is Air National Guard but some of it isn't. Not sure why they'd be flying dirty but they are. Helicopters are the worst offenders. We can visually see them but usually can't catch a tail number.
 

3rdGen4R

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I figured for sure you'd have an ADS-B setup at home already, Dan!

One thing we've noticed is a lot of low flying air traffic near my parents with their transponders turned off. Some of it is Air National Guard but some of it isn't. Not sure why they'd be flying dirty but they are. Helicopters are the worst offenders. We can visually see them but usually can't catch a tail number.
What airspace is in your parents area? If you are in class E you are only required to have ADS-B at 10,000 feet MSL. Look up 91.215. Most likely they aren't doing anything illegal at all.
 

DouglasVB

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I don't really know how to read sectional charts... When I look at this: https://sua.faa.gov/sua/siteFrame.app they're in the Foothill 1 MOA which is on the San Francisco VFR sectional chart. Their house is at 6000 ft. One mile away the terrain tops out at 7500 ft and seven miles away it tops out at 10300 ft. About three miles away there's a 9800 ft prominence. There is wilderness area about 5 miles from them.
 

DaveInDenver

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I don't really know how to read sectional charts... When I look at this: https://sua.faa.gov/sua/siteFrame.app they're in the Foothill 1 MOA which is on the San Francisco VFR sectional chart. Their house is at 6000 ft. One mile away the terrain tops out at 7500 ft and seven miles away it tops out at 10300 ft. About three miles away there's a 9800 ft prominence. There is wilderness area about 5 miles from them.
I believe it's class E if I understand things right. Acknowledging I know next to nothing as well, just like to look at maps and read about stuff.


Screen Shot 2021-09-11 at 9.53.36 AM.png


Screen Shot 2021-09-11 at 10.08.06 AM.png
 
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3rdGen4R

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If hey are in the MOA (Military use) airspace it’s class g most of the time. So it’s not required to use ADS-B.
 
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