When your near the ground it acts as a ground plane and reflects the signals from the planes above you. But when your at 400' you lose the ground plane. Try a clover leaf or a spider instead. And also the planes adsb are designed to be picked up by ground stations so their antennas point downwards. Just a thought.
Mostly is an antenna problem beacuse other planes in the sky use the same signals to keep track of each other, I have a tracking station on the roof so...
I grew up in Danville and used to ride my motorcycle up the mountain all the time. I haven't been there in over 20 years but I still recognize your drive up the mountain. Great memories from that mountain and my numerous camping trips there.
Nice job. Great technical improvisational skills. You are good at walking and talking through technical issues on your feet. Since these are the real-life issues one faces while in the field.
You need to find the RF study of that mass of hi power RF behind you...you are in the dead zone on the ground so visitors don’t get high RF exposure. As you climbed with the drone you probably flew right into some hot transmissions saturating your receiver. Fly your RF sniffer around and map your fields looking for high levels and nulls. Also figure a way check your input saturation on your dongle....”you were listening for crickets right next to the stadium loud speakers -metaphorically” . Perhaps you might need to find an RF quiet mountain top or just a good discone with ground plane on the roof of your building...
I want to thank you two for the wealth of information on your channel. I happened upon your SDR series kinda by accident. I've been into scanner monitoring for about 35+ years and the hobby has gotten stale due to first responders going to encrypted protocols such as P25. But now monitoring planes, ships, etc as made it exciting again. You guys break things down into layman's terms and your experiments are very exciting!!! Thank you again for giving me new ideas.
Shannon & Darren I appreciate the fact that you looked up the FAA regs on R/C flight. As an aviation mechanic (not a pilot yet :) ) I love ALL aspects of aviation. You are setting a standard on how things should be done.
ADS-B is 1090 MHz; it wouldn't surprise me in the least that you began getting a lot of interference from the adjacent antenna farm. Another thing, as you get more and more signals, False Replies Unsynchronized in Time (FRUIT) from the transponders may be stepping on the ADS-B broadcasts causing signals which are really present to be discarded.
Being close to those antenna towers certainly didn't help. The dongle was effectively jammed by the antenna tower's transmitter signals. Your high gain colinear antenna only made it worse. Their transmit power (and your higher gain antenna) which could overload the receiver dongle (which mixes all the RF signals also) causing the dongle to attenuate all received signals by the same factor, but the desired signal is so weak compared to the radiated power of the tower, your adsb drops into the noise and all is lost. So yes, it did work a bit better with a 2 element colinear antenna than it did with a 16 element antenna because less power was feeding into the dongle and it wasn't as overloaded.
2 Things.. First, you were mis-interpreting when you were losing the signal.. Each entry shows the last time the beacon was heard.. It is timing out at 60 seconds, so you need to look for beacon times that are low (1-5 seconds) to know when you just received something, and when Shannon is saying "we lost them.." you really lost them a whole minute prior, and they just timed out off of the screen.. Second, I agree with some of the other comments - I think the motors are interfering with the SDR dongle.. So, you are receiving a small number of planes on the ground, and when you take off, you swamp the radio, and slowly as you climb up, they're timing out.. Perhaps a USB extension to get that radio dangling a little bit further below the quad, or maybe devise some kind of shielding for the USB dongle??
I haven't watched for awhile, but man Daren you and Shannon both have exceeded the skills necessary to become an Amateur Radio Operator and REALLY open another world of experimenting and tinkering! Get with the HamNation guy's over at TWIT and get your license! Leo did it, you can EASILY , you both could probably just test up to General in one session! 73
Hello everyone, Thanks Darren, Shannon and the team for this greats experiments, now let me do some recomendations with this last one experiment :) 1- Back to la montaña del diablo again. 2- Use the same last scenario BUT using "rtl_tcp" to SEE what is happening with the signal at 1090MHz using SDR# (SDRsharp) over TCP/IP, and in that way we will see what is interfering or how much clean is this RF band. 3- Record the Montaña del Diablo part 2. I cant wait to see what happend :D~ ,come one guys go ahead !. Thanks a lot for your amazing work.
I know this video was a while ago, but thought I'd pass on some recent experience (today). I just moved my antennacraft st2 from ground level mounted on a 10 foot mast, to the top of my house (chimney mount) which puts the st2 at approximately 30 feet above ground. I'm at 250 feet ASL (Vancouver, Washington). Today I was tracking aircraft 300 NM from my house using adbscope, the "NooElec" RTL-SDR dongle and that st2 on the roof. So it appears there's no need to go so high as 400 agl. :-)
For me, it's more interesting when something like this happens. If everything goes according to the plan, it's kinda boring. Trying to debug those problems is a lot of fun.
The DJI radio also use 2.4 GHz... it use wider spectrum and use bigger power than wifi... so your 2.4GHz wifi is jammed by DJI system... please try again with 5.4GHz wifi... good luck...
PS, the advantage of the 'slim jim' antenna over an open rod, is that it is in fact a closed loop. Your rod antenna, in any form, is off-resonance just a wire that will pick up any signal, while the closed loop is a short for off-resonance signals, especially those lower than the resonance. This prevents overloading the DVB stick by alien (:-) ) signals. I use 2 slim jims, one for 70 cm amateur radio, and one for about 160 MHz AIS ship identification signals. Both work very very good. A 1090 MHz one would be really really small. Looking for ship AIS at about 160 MHz would be a much better demo for showing the effect of drone height, as the distance is in km 4 * (sqrt(height_transmitter) + sqrt(height_receiver) ) (heights in meters) and ships will usually be quite low. There is plenty of software around for receiving AIS, for example opencpn. I do that my way: panteltje.com/panteltje/xgpspc/index.html Yes I am into using the antenna on my drone too, but want to power the drone via the same coax that the antenna uses, so it can stay up as long as I want, work in progress, at least my H501S has brushless motors.. Hope any of this helps. :-)
Really the only explanations for the sudden loss of signal at a specific height are interference from the microwave dishes nearby, or temperature at the high altitudes effecting the signals stability
Dump1090 was dropping the flights above 50 ft, even before they disappeared from the list (since time seen was increasing steadily until it deletes them after 60 seconds). My money is also on the nearby tower. You ought to try again with a simple FFT running at 1090mhz, as you climb in altitude. To do that with the pineapple you'd probably need to run GR and have it decimate the incoming radio data, taking 1024 samples every 1/30th second, or something like that, saving to SD ... then you could run an FFT on the ground. I bet we'd see a steady increase in interference as you climb. Another thing to check is that you are using auto gain on the RTL. That might help deal with the nearby tower interference if it's pushing your total rx power up too high. Great test!
Thanks for the Video especially in this case where not everything worked out perfectly, just by admitting a fault we can learn and Improve things. I know lot of comments are like “you should this and that” but hey learning by burning or ;) From my Point I looks all fine, the Antennas in the Background won’t be a big issue these are Point to Point connections with directional antennas your fare above them and they operate in usually in higher frequency’s (these days) and no broadcasting station is near the ADS-B Band. You are on such a Exposed spot and Airplanes have really strong signal you can receive signals without a connected Antenna so the Gain seems to be the biggest Issue obviously What about using a Symmetric Dipole mounted on the Side so you could “follow” the Plane that would also help to keep General Noise down. May also worth to look into the Drone itself using (additional) ferrites and /or shielded cable for every cable which is connected with the Motor, these are Brushless DC Motors with frequency converter which are known as not “EMV friendly” and cause a lot of noise, proportional to your RPM so both point the High gain and the high gain source g what about a Symmetric Dipole for the RTL and inside the Drone using ferrites and /or shielded cable for every cable which is connected to the Motor, the normaly use Brushless DC Motors with frequency converter
If that messes with you don't even think about San Bruno MT. You'd might as well go hang out @Sutro. What other high places do you have that have not been touched inappropriately by radio infrastructure?
There is a lot of electrical/radio noise generated from the four motors on the quadcopter. Altitude was not the issue. If you used a balloon you'd verify radio noise vs. altitude.
something you guys could try is using a kite to hold your pineapple. I don't know what the wind speeds on your mountain are like but it could be an interesting way of sustained flight for the pineapple.
Whats funny is if you look in the seen colom it counts to 60 and drops. So therefore the signal was lost one minute befor 400 Ft. However a ground plane would probabily help.
awesome video. maybe next time you could try a helium balloon, also stay away from transmitter towers. use horizontally polarized antennas for the wifi. great fun. :)
You could make dump1090 use binary encoding ADS B supports that so you could watch it live. You could also use screen so if you lose connection, the session doesn't stop, it keeps running in the background. Love the show!
it looked to me as if Sharon reported signals were lost, when in fact they were lost 60 seconds before; the 'last seen' figure in the last column kept rising until it was at 60 sec, leading me to believe it was the antenna after all.
4 possible theories why it would fail to catch a signal at an altitude: - Too many packets for the CPU to process in time, aka CPU overflow. CPU utilization was about 100% when processing samples. To verify this, either use a more powerful system or reduce RF gain in dump1090 to a lower level. - RF interference from the nearby tower - increasing EMF from the electric motors ramping up - wind/cold/heat affecting the dongle chip or crystal performance (frequency deviation?)
Note on the 2.4GHz isuse: Remote of quadcopters are they 2.4GHz Same question goes for video transmitters on the quads. Suggestion for the future experiments: if you were to use some DIY quad with RC receiver that supports telemetry(check FRsky) you could connect the uart of the pineapple directly to the receiver and using FTDI cable connect the remote to the PC. This way you'll get at least 2km of range for ssh/telnet.
Looks like you guys had great time even if it was a bit of a fail. I have a feeling one of those antenna towers were interfering with the results, if you look at the output, the "last seen" time starts going up as soon as you started to climb. Wish i could afford an SDR Drone :)
I attempted something similar but with VHF voice. The issue is the RF interference caused by the motors on the Phantom. Next time use shielded coax to get the antenna as far away from the quad as possible.
I am wondering if the antenna had too many elements. This would have the affect of squashing the lobes on the antenna - so planes below and above the horizontal plane of the antenna will be missed.
Because the planes have very strong 1090 MHz signals, they are much easier to receive than a GPS satellite. So, even a small low gain 1090 antenna will work wonders on a nice high hill top.. (Since the planes will be line-of-sight). I have a pretty good antenna setup and a cheap dongle feeding RTL1090 and I'm seeing planes out to about 172 miles.. Only using the RTL AGC and leaving the other one off..
Put Your antenna in a sleeve of heat shrink tubing you can buy it by the foot! It would make your antenna more durable. Also your antenna probably likes a Ground Plane!
+Hak5 I *DEMAND* that you guys redo this with a WiFi Pineapple Terra, this did not go too well, and the Terra has many more antennas to capture your AP's signal.
Do you use resistor termination on your colinear antenna? I am using 50 ohm on the end of my colinear between that two feeds and its working fine and in my opinion even better. You should try it. Just saying...
Would have been nice if you had an extra drone and a couple more of them alfa cards. Send one up to the altitude you was trying for, use the second drone with a alfa card as a relay and the third for video.
You almost certainly where losing connection because of the nearby microwave antennas behind you. When the colinear was longer the problem is worse because the antenna can pick up more energy from the nearby transmitters, overloading the front end of the sdr receiver even more so. When the copter was on the ground, the receiving pattern of the colinear is actually effected by the ground and probably has a more “vertical” pattern, shielding it from the antennas to the horizontal. When in the air this ground effect wouldn’t happen any more. I’m guess you were just lucky that you didn’t lose wifi connection to the pineapple. Also, the dongle probably just has crappy front end circuitry. My two cents worth anyway. Great show.
The tower probably didn't help, but you could also be degraded from the emf of the electric motors of the quad copter. Perhaps helium balloons and a tether could give a longer up time without the digital noise.
but they got planes when the drone was hovering low (around eye level), wouldn't there be just as much interference from the motors at that level as at 400 ft? I guess there is more strain when climbing, but would that really make such difference?
Muromuro I get ATSC stations on my HDTV when my LED lights are on in the house. But I get a lot more stations when they're off. Just something low tech to try to potentially improve the signal (or the landings).
wwwShadow7 And I agree that it might be a problem, but my point was that if the engines are on wouldn't they produce same amount of interference no matter how high you are flying? Considering they got 10+ planes while hovering low and lost all of them when they flew higher.
Muromuro It is by no means the only influence. Perhaps the van or human bodies provided some shielding from the primary influences. Or the lower wind provided the proper orientation of the attennae when down low.
ya, I'm thinkin a simple moxon or even a inverted v dipole out the top built with a coat hanger would be the better way to go up that high, even an cloverleaf built around 33cm band - but ya the kite tail fail ... + you have no ground propo and a whole lotta RF on that Mtn. top. - If you took your tech license you would understand what was happening :) Some keywords to look up: RF Phase , wavelength, polarization, antenna resonance.
You were loosing connection between the modem ( on Drone ) and the receiver card with antenna on table ! I think that was the problem. It was very obvious I guess .I don't know why you did not pay attention to that part ?!
I am thinking that big ass array behind is killing the frames. Even if nothing else is running on 2.4. Same thing happen when my Neighbor got into HAM radio. every time he transmitted it would wreak havoc on our Wifi. still had connection but nothing would transfer. Drop on a sniffer and see what the Frames are looking like.
Hey, Hak5 / Shannon Morse / ***** just a quick thought (I'm at 21:27 into the episode); when you are shooting the quad up in the air, I'm noticing that the right-most col on the term session (labeled 'seen') keeps on climbing...and right about when they reach 60s, they drop from the screen. My thought -- and keep in mind I haven't played w/ any of the awesome equipment you guys are rocking -- is that you are losing the connection much sooner (ie, closer to the ground), and by the time you've climbed to 400ft, the 60s period has elapsed and thus the airplanes are appearing to drop from the capture, when in reality the SDR stopped seeing them when the quad was much closer to the ground... this 'seen' col could be when a signal from the particular aircraft was last seen w/ a default of 60s to no longer show the aircraft in the output.. Totally open to your thoughts, like I said, I haven't actually had a chance to play with any of this cool stuff (yet!), so I could be totally wrong!
I suppose I should also note, that this does not explain why getting, oh, 6+ ft off the ground doesn't yield the signals...that is unless of course those towers are interfering. Sadly, I don't know that much about antenna theory. But wait, heres another hypothesis...(my 6ft comment made this thought pop into my head)!!! At 20:54, and I quote "Perhaps some of this crazy stuff.."..so, say theres interference; note the position of the quad in relation to everything else around; towers (one near, one on the other side of the parking lot), van, fence... could perhaps the van/fence be blocking some interfering signals, and thus when the quad is at a lower alt, you are seeing aircraft? As the quad flew closer to the van (thus blocking more interfering signals) around 21:21, Shannon sees a bunch more...then Darren shoots the quad high in the sky, and all I can see is the 'Seen' col (which I'm assuming is the duration since the last packet/signal from that aircraft has been seen) increment until they all reach 60s and drop off completely. I'd be curious to know what happens when the following 3 things are controlled/watched more closely; position of the quad in relation to the ground (aka height); position of the quad in relation to the towers/van; and the value as reported in the 'Seen' col. I'd suspect that if the same conditions were to exist (placement of van, and quad specifically), and the quad incremented say a foot every 10 sec (enough time for dump1090 to see some fresh packets), that perhaps once the quad (or better yet, the antenna) got above the van's height, it would lose some/all of the signals. I'd love to come kick it with you guys and give this a test...but sadly, I'm not in CA :(
I would theroize there was significant front end overload and or signal mixing due to the wi-fi, the ADSB rcvr @ 1090 Mhz & the microwave links on the tower. At a 20 dollar price point , the ADSB reciever would not have the necessary front end filtering to handle mixing & adjacent frequency interference. Properly filtered microwave products cost many 1000's of dollars. It would be neet to see what RF enviroment up there is like with a Spectrum analyzer of sufficent bandwidth, most very high hil top locations will have MW transmitters that could be up in the 10's of GHz, hence the large , high gain parabolic antennas. What you could do.. is take a yagi up there, as its directional.. & point it as a known area of high air traffic that is away from the direction of that communications tower. The yagi being directional would provide 'some' rejection of those signals, however due to the close proximity, it may not eliminate them in its entirety. Was a cool episode none the less!
Bigger is not always better with antennas. ADSB runs at 1090mhz which means the full wavelength is just over 5 inches. Anything more than that will offset the resonant frequency and negatively effect reception.
dude you are swamping the sdr dongle ..rtl sdr dongles have no filtering or band pass..you are so close to that microwave tower it will kill the dongle :)
+luis morel Ask the Federal Communications Commission or the Federal Aviation Administration. I am sure they would like to help you into a prison cell.
well the reason i need this is due to the reason that my cuntry has only 1 search and rescue plane and it was being fix when 1 of my friends boats went down and he drownd now my goal is to build this not to go high up but to go long distance to help as a voluntery helper in search and rescue where i live its a small island with alot of boating going on alot of ppl drown every week here and i want to try and help how ever i can to try and provent this and get erly help to them
+luis morel that´s a very good idea, I have also tough about a search and rescue drone (most likely search only but you got the point). Its quite difficult to get 300 mile range on a budget but nothing is impossible. from my research I found that people have used wifi networks to communicate with a ardupilot or a pixhawk board with some sort of serial to ethernet adapter and used ip cameras for live video feed. (there is a pretty good video on youtube with a guy that used a ubiquiti nanostation to do that but I can't find it anywhere) but you could use the same principle of a network encapsulation and use a backhaul radio like the ubiquiti rocket m (specially the 900mhz version) and high gain antennas and a antenna tracker for the base station. if you want to talk more about that idea please PM me on google+ or youtube I´d love to help you out and a lot of other people. specially if the project is replicable for other places like poor countries. btw what country do you live in ?
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When your near the ground it acts as a ground plane and reflects the signals from the planes above you. But when your at 400' you lose the ground plane. Try a clover leaf or a spider instead. And also the planes adsb are designed to be picked up by ground stations so their antennas point downwards. Just a thought.
Dispicable Kami Here is a smart person, so many comments but one smart person!
Mostly is an antenna problem beacuse other planes in the sky use the same signals to keep track of each other, I have a tracking station on the roof so...
@@Rapbando Planes and ships use the skin of the craft as a ground plane
I grew up in Danville and used to ride my motorcycle up the mountain all the time. I haven't been there in over 20 years but I still recognize your drive up the mountain. Great memories from that mountain and my numerous camping trips there.
Love the direction you're taking the show. I can't wait to see what you come up with next. Thank you for reminding me how my fun radio can be.
It was a pity the coax was damaged, but it was a nice day up there. Drones, tech and snow balls, oh my.
Nice job. Great technical improvisational skills. You are good at walking and talking through technical issues on your feet. Since these are the real-life issues one faces while in the field.
You need to find the RF study of that mass of hi power RF behind you...you are in the dead zone on the ground so visitors don’t get high RF exposure. As you climbed with the drone you probably flew right into some hot transmissions saturating your receiver. Fly your RF sniffer around and map your fields looking for high levels and nulls. Also figure a way check your input saturation on your dongle....”you were listening for crickets right next to the stadium loud speakers -metaphorically” . Perhaps you might need to find an RF quiet mountain top or just a good discone with ground plane on the roof of your building...
I want to thank you two for the wealth of information on your channel. I happened upon your SDR series kinda by accident. I've been into scanner monitoring for about 35+ years and the hobby has gotten stale due to first responders going to encrypted protocols such as P25. But now monitoring planes, ships, etc as made it exciting again. You guys break things down into layman's terms and your experiments are very exciting!!! Thank you again for giving me new ideas.
Next step - get your ham radio license! I just got mine! - Shannon
I'm kinda surpised that Phantom 2 vision's 5.8GHz control rx didn't wig out and lose control so close to that microwave tower.
"Yes, lets try this experiment 50 feet from a Radio tower with a dozen or so microwave transmitters and wonder why it doesn't work..."
yeah
That sure is a cool visual, with the two drones up above the mountain.
It's so frakkin' cool!
Shannon & Darren I appreciate the fact that you looked up the FAA regs on R/C flight. As an aviation mechanic (not a pilot yet :) ) I love ALL aspects of aviation. You are setting a standard on how things should be done.
i LOVE seeing you guys working on a great hack and learn real!
ADS-B is 1090 MHz; it wouldn't surprise me in the least that you began getting a lot of interference from the adjacent antenna farm. Another thing, as you get more and more signals, False Replies Unsynchronized in Time (FRUIT) from the transponders may be stepping on the ADS-B broadcasts causing signals which are really present to be discarded.
Being close to those antenna towers certainly didn't help. The dongle was effectively jammed by the antenna tower's transmitter signals. Your high gain colinear antenna only made it worse. Their transmit power (and your higher gain antenna) which could overload the receiver dongle (which mixes all the RF signals also) causing the dongle to attenuate all received signals by the same factor, but the desired signal is so weak compared to the radiated power of the tower, your adsb drops into the noise and all is lost. So yes, it did work a bit better with a 2 element colinear antenna than it did with a 16 element antenna because less power was feeding into the dongle and it wasn't as overloaded.
2 Things.. First, you were mis-interpreting when you were losing the signal.. Each entry shows the last time the beacon was heard.. It is timing out at 60 seconds, so you need to look for beacon times that are low (1-5 seconds) to know when you just received something, and when Shannon is saying "we lost them.." you really lost them a whole minute prior, and they just timed out off of the screen.. Second, I agree with some of the other comments - I think the motors are interfering with the SDR dongle.. So, you are receiving a small number of planes on the ground, and when you take off, you swamp the radio, and slowly as you climb up, they're timing out.. Perhaps a USB extension to get that radio dangling a little bit further below the quad, or maybe devise some kind of shielding for the USB dongle??
I use a kite and it works good.
you made my day with that comment :D
I haven't watched for awhile, but man Daren you and Shannon both have exceeded the skills necessary to become an Amateur Radio Operator and REALLY open another world of experimenting and tinkering! Get with the HamNation guy's over at TWIT and get your license! Leo did it, you can EASILY , you both could probably just test up to General in one session! 73
The tower beside you probably had a beefy crystal oscillator..... And owned your signals.
Great show! Sometimes we learn best from failed experiments.
Great show :-) more outdoor shows like this :-)
Hello everyone, Thanks Darren, Shannon and the team for this greats experiments, now let me do some recomendations with this last one experiment :)
1- Back to la montaña del diablo again.
2- Use the same last scenario BUT using "rtl_tcp" to SEE what is happening with the signal at 1090MHz using SDR# (SDRsharp) over TCP/IP, and in that way we will see what is interfering or how much clean is this RF band.
3- Record the Montaña del Diablo part 2.
I cant wait to see what happend :D~ ,come one guys go ahead !.
Thanks a lot for your amazing work.
My bet is the motors on the quad put out horrendous noise.
I know this video was a while ago, but thought I'd pass on some recent experience (today). I just moved my antennacraft st2 from ground level mounted on a 10 foot mast, to the top of my house (chimney mount) which puts the st2 at approximately 30 feet above ground. I'm at 250 feet ASL (Vancouver, Washington).
Today I was tracking aircraft 300 NM from my house using adbscope, the "NooElec" RTL-SDR dongle and that st2 on the roof.
So it appears there's no need to go so high as 400 agl. :-)
When I made my colinear before, i soldered 50 ohm resistor between ends and i think it helped improve reception a lot.
you guyzz are awesome,
I always enjoy watching your show
love you guyzz @hak5
the rf energy from those hot towers and atennas will mess with that signal like crazy .
For me, it's more interesting when something like this happens. If everything goes according to the plan, it's kinda boring. Trying to debug those problems is a lot of fun.
Perhaps the van right next to them is acting like some sort of big antenna or reflector?
the antenna on the Airplane are pointed down. so if you get up you are getting out of range. probably the RF station is for Airplanes too.
The DJI radio also use 2.4 GHz... it use wider spectrum and use bigger power than wifi... so your 2.4GHz wifi is jammed by DJI system...
please try again with 5.4GHz wifi... good luck...
PS, the advantage of the 'slim jim' antenna over an open rod, is that it is in fact a closed loop.
Your rod antenna, in any form, is off-resonance just a wire that will pick up any signal,
while the closed loop is a short for off-resonance signals, especially those lower than the
resonance.
This prevents overloading the DVB stick by alien (:-) ) signals.
I use 2 slim jims, one for 70 cm amateur radio, and one for about 160 MHz AIS ship identification signals.
Both work very very good.
A 1090 MHz one would be really really small.
Looking for ship AIS at about 160 MHz would be a much better demo for showing the effect of drone height,
as the distance is in km 4 * (sqrt(height_transmitter) + sqrt(height_receiver) ) (heights in meters)
and ships will usually be quite low.
There is plenty of software around for receiving AIS, for example opencpn.
I do that my way:
panteltje.com/panteltje/xgpspc/index.html
Yes I am into using the antenna on my drone too, but want to power the drone via the same coax that the antenna uses,
so it can stay up as long as I want, work in progress, at least my H501S has brushless motors..
Hope any of this helps.
:-)
Really the only explanations for the sudden loss of signal at a specific height are interference from the microwave dishes nearby, or temperature at the high altitudes effecting the signals stability
Dump1090 was dropping the flights above 50 ft, even before they disappeared from the list (since time seen was increasing steadily until it deletes them after 60 seconds).
My money is also on the nearby tower. You ought to try again with a simple FFT running at 1090mhz, as you climb in altitude. To do that with the pineapple you'd probably need to run GR and have it decimate the incoming radio data, taking 1024 samples every 1/30th second, or something like that, saving to SD ... then you could run an FFT on the ground. I bet we'd see a steady increase in interference as you climb.
Another thing to check is that you are using auto gain on the RTL. That might help deal with the nearby tower interference if it's pushing your total rx power up too high.
Great test!
Thanks for the Video especially in this case where not everything worked out perfectly, just by admitting a fault we can learn and Improve things.
I know lot of comments are like “you should this and that” but hey learning by burning or ;)
From my Point I looks all fine, the Antennas in the Background won’t be a big issue these are Point to Point connections with directional antennas your fare above them and they operate in usually in higher frequency’s (these days) and no broadcasting station is near the ADS-B Band.
You are on such a Exposed spot and Airplanes have really strong signal you can receive signals without a connected Antenna so the Gain seems to be the biggest Issue obviously
What about using a Symmetric Dipole mounted on the Side so you could “follow” the Plane that would also help to keep General Noise down.
May also worth to look into the Drone itself using (additional) ferrites and /or shielded cable for every cable which is connected with the Motor, these are Brushless DC Motors with frequency converter which are known as not “EMV friendly” and cause a lot of noise, proportional to your RPM so both point the High gain and the high gain source
g what about a Symmetric Dipole for the RTL and inside the Drone using ferrites and /or shielded cable for every cable which is connected to the Motor, the normaly use Brushless DC Motors with frequency converter
Wow! This is exactly my kind of nerd hobby! :) keep'em comming, i'll watch! :)
The RF from all the nearby arrays overloaded the front-end of your dongle.
Thus reducing the amount of detected aircraft.
If that messes with you don't even think about San Bruno MT. You'd might as well go hang out @Sutro. What other high places do you have that have not been touched inappropriately by radio infrastructure?
how crushed you get when she says @22:30 you get a whole lot more when you put it on the table XD
your working is professional
totally worth trying, don't give up
Also, you did notice the HUGE transmitter station behind you, making the place a RF HELL.....
There is a lot of electrical/radio noise generated from the four motors on the quadcopter. Altitude was not the issue. If you used a balloon you'd verify radio noise vs. altitude.
They all started dropping when it got around 60 secs. I'm thinking they dropped long before that but they 'drop' off the screen at around 60 secs.
something you guys could try is using a kite to hold your pineapple. I don't know what the wind speeds on your mountain are like but it could be an interesting way of sustained flight for the pineapple.
Whats funny is if you look in the seen colom it counts to 60 and drops. So therefore the signal was lost one minute befor 400 Ft. However a ground plane would probabily help.
you know, in your situation its actually easier to just grab the drone by landing gear instead of trying to land it.
awesome video. maybe next time you could try a helium balloon, also stay away from transmitter towers. use horizontally polarized antennas for the wifi. great fun. :)
Big idea the wifi as bridge to the ground - data from an USB SDR - great
You could make dump1090 use binary encoding ADS B supports that so you could watch it live. You could also use screen so if you lose connection, the session doesn't stop, it keeps running in the background. Love the show!
Inspired me to dig out one of my spare rtl2832's and set mine up , with a realtime webfeed.
www.vk2tob.com
The perfect antenna for an SDR is really a discone.. VK2TOB.
it looked to me as if Sharon reported signals were lost, when in fact they were lost 60 seconds before; the 'last seen' figure in the last column kept rising until it was at 60 sec, leading me to believe it was the antenna after all.
Can this be used to track domestic drones?
all the hackery loving it.
Shannon can rock my Pineapple ;)
4 possible theories why it would fail to catch a signal at an altitude:
- Too many packets for the CPU to process in time, aka CPU overflow. CPU utilization was about 100% when processing samples. To verify this, either use a more powerful system or reduce RF gain in dump1090 to a lower level.
- RF interference from the nearby tower
- increasing EMF from the electric motors ramping up
- wind/cold/heat affecting the dongle chip or crystal performance (frequency deviation?)
Note on the 2.4GHz isuse:
Remote of quadcopters are they 2.4GHz
Same question goes for video transmitters on the quads.
Suggestion for the future experiments:
if you were to use some DIY quad with RC receiver that supports telemetry(check FRsky) you could connect the uart of the pineapple directly to the receiver and using FTDI cable connect the remote to the PC. This way you'll get at least 2km of range for ssh/telnet.
Looks like you guys had great time even if it was a bit of a fail.
I have a feeling one of those antenna towers were interfering with the results, if you look at the output, the "last seen" time starts going up as soon as you started to climb.
Wish i could afford an SDR Drone :)
I attempted something similar but with VHF voice. The issue is the RF interference caused by the motors on the Phantom. Next time use shielded coax to get the antenna as far away from the quad as possible.
+tivowillieb +tivowillieb It's not the motors unless they have brushes bud, Guarantee ya it's the ESC's
Van made it a Van-tenna (and protection from that array on the mountain)?
I am wondering if the antenna had too many elements. This would have the affect of squashing the lobes on the antenna - so planes below and above the horizontal plane of the antenna will be missed.
Because the planes have very strong 1090 MHz signals, they are much easier to receive than a GPS satellite. So, even a small low gain 1090 antenna will work wonders on a nice high hill top.. (Since the planes will be line-of-sight).
I have a pretty good antenna setup and a cheap dongle feeding RTL1090 and I'm seeing planes out to about 172 miles.. Only using the RTL AGC and leaving the other one off..
Did you find MH370?
Put Your antenna in a sleeve of heat shrink tubing you can buy it by the foot! It would make your antenna more durable. Also your antenna probably likes a Ground Plane!
Whats with the screen capture on that laptop!?!?!?!
Answer in short is that the tower is rebroadcasting the data across the valley for other authorities. You end up out of line of sight.
+Hak5 I *DEMAND* that you guys redo this with a WiFi Pineapple Terra, this did not go too well, and the Terra has many more antennas to capture your AP's signal.
Never mind... I saw this when it was new, and I never saw the follow up (EP 1613), and just assumed it didn't exist... Sorry... :/
22:00 Awkward moment when she was actually disconnected and the timeout is 60 seconds -.-
saik0pod ikr
They still had a connection tot he pineapple but not to the planes
@Alex Nicholson fwiw, that's seconds since the last packet received from aircraft
wohoo elevation is overkill.. with just a quarter wave antenna.. for sure youre receiving 50-100 planes ..
Maybe the airplanes antenna are pointed downwards?
Not only is the NSA is watching.... You can too!
Every 1 is still watching the Archive version of Giant Bombs PAX panel, Went up a little bit b4 this video.
24:56 That moment when you put another drone 400ft above a drone that's already 400ft above ground level because the drone is a surface...
Do you use resistor termination on your colinear antenna? I am using 50 ohm on the end of my colinear between that two feeds and its working fine and in my opinion even better. You should try it. Just saying...
Would have been nice if you had an extra drone and a couple more of them alfa cards. Send one up to the altitude you was trying for, use the second drone with a alfa card as a relay and the third for video.
You almost certainly where losing connection because of the nearby microwave antennas behind you. When the colinear was longer the problem is worse because the antenna can pick up more energy from the nearby transmitters, overloading the front end of the sdr receiver even more so. When the copter was on the ground, the receiving pattern of the colinear is actually effected by the ground and probably has a more “vertical” pattern, shielding it from the antennas to the horizontal. When in the air this ground effect wouldn’t happen any more. I’m guess you were just lucky that you didn’t lose wifi connection to the pineapple. Also, the dongle probably just has crappy front end circuitry.
My two cents worth anyway. Great show.
what you should also do in solder it...
What's up with the lack of refresh on the laptop display?
The tower probably didn't help, but you could also be degraded from the emf of the electric motors of the quad copter. Perhaps helium balloons and a tether could give a longer up time without the digital noise.
but they got planes when the drone was hovering low (around eye level), wouldn't there be just as much interference from the motors at that level as at 400 ft? I guess there is more strain when climbing, but would that really make such difference?
Muromuro I get ATSC stations on my HDTV when my LED lights are on in the house. But I get a lot more stations when they're off. Just something low tech to try to potentially improve the signal (or the landings).
wwwShadow7 And I agree that it might be a problem, but my point was that if the engines are on wouldn't they produce same amount of interference no matter how high you are flying?
Considering they got 10+ planes while hovering low and lost all of them when they flew higher.
Muromuro It is by no means the only influence. Perhaps the van or human bodies provided some shielding from the primary influences. Or the lower wind provided the proper orientation of the attennae when down low.
ya, I'm thinkin a simple moxon or even a inverted v dipole out the top built with a coat hanger would be the better way to go up that high, even an cloverleaf built around 33cm band - but ya the kite tail fail ... + you have no ground propo and a whole lotta RF on that Mtn. top. - If you took your tech license you would understand what was happening :) Some keywords to look up: RF Phase , wavelength, polarization, antenna resonance.
why did you use 9dbi antenna for RX? 9dbi wides range laterally by reducing vertical range.
You were loosing connection between the modem ( on Drone ) and the receiver card with antenna on table ! I think that was the problem. It was very obvious I guess .I don't know why you did not pay attention to that part ?!
I am thinking that big ass array behind is killing the frames. Even if nothing else is running on 2.4. Same thing happen when my Neighbor got into HAM radio. every time he transmitted it would wreak havoc on our Wifi. still had connection but nothing would transfer. Drop on a sniffer and see what the Frames are looking like.
What's wrong with the screengrab ghost's?
May be the van was acting like a nice reflector..
Hey, Hak5 / Shannon Morse / ***** just a quick thought (I'm at 21:27 into the episode); when you are shooting the quad up in the air, I'm noticing that the right-most col on the term session (labeled 'seen') keeps on climbing...and right about when they reach 60s, they drop from the screen.
My thought -- and keep in mind I haven't played w/ any of the awesome equipment you guys are rocking -- is that you are losing the connection much sooner (ie, closer to the ground), and by the time you've climbed to 400ft, the 60s period has elapsed and thus the airplanes are appearing to drop from the capture, when in reality the SDR stopped seeing them when the quad was much closer to the ground... this 'seen' col could be when a signal from the particular aircraft was last seen w/ a default of 60s to no longer show the aircraft in the output..
Totally open to your thoughts, like I said, I haven't actually had a chance to play with any of this cool stuff (yet!), so I could be totally wrong!
I suppose I should also note, that this does not explain why getting, oh, 6+ ft off the ground doesn't yield the signals...that is unless of course those towers are interfering. Sadly, I don't know that much about antenna theory.
But wait, heres another hypothesis...(my 6ft comment made this thought pop into my head)!!! At 20:54, and I quote "Perhaps some of this crazy stuff.."..so, say theres interference; note the position of the quad in relation to everything else around; towers (one near, one on the other side of the parking lot), van, fence... could perhaps the van/fence be blocking some interfering signals, and thus when the quad is at a lower alt, you are seeing aircraft? As the quad flew closer to the van (thus blocking more interfering signals) around 21:21, Shannon sees a bunch more...then Darren shoots the quad high in the sky, and all I can see is the 'Seen' col (which I'm assuming is the duration since the last packet/signal from that aircraft has been seen) increment until they all reach 60s and drop off completely.
I'd be curious to know what happens when the following 3 things are controlled/watched more closely; position of the quad in relation to the ground (aka height); position of the quad in relation to the towers/van; and the value as reported in the 'Seen' col. I'd suspect that if the same conditions were to exist (placement of van, and quad specifically), and the quad incremented say a foot every 10 sec (enough time for dump1090 to see some fresh packets), that perhaps once the quad (or better yet, the antenna) got above the van's height, it would lose some/all of the signals.
I'd love to come kick it with you guys and give this a test...but sadly, I'm not in CA :(
I would theroize there was significant front end overload and or signal mixing due to the wi-fi, the ADSB rcvr @ 1090 Mhz & the microwave links on the tower. At a 20 dollar price point , the ADSB reciever would not have the necessary front end filtering to handle mixing & adjacent frequency interference. Properly filtered microwave products cost many 1000's of dollars. It would be neet to see what RF enviroment up there is like with a Spectrum analyzer of sufficent bandwidth, most very high hil top locations will have MW transmitters that could be up in the 10's of GHz, hence the large , high gain parabolic antennas. What you could do.. is take a yagi up there, as its directional.. & point it as a known area of high air traffic that is away from the direction of that communications tower. The yagi being directional would provide 'some' rejection of those signals, however due to the close proximity, it may not eliminate them in its entirety. Was a cool episode none the less!
second time viewing... love it
Shannon: what laptop in that you have in the studio
Where can I get one of those faa cheat sheets?
The Revision 3 stuff that comes up is a real nuisance.
So what's the use of this activity again?
They shouldve compared it to their gigantic dipole antenna. But my bets are that the giant antenna would easily beat the drone.
Do drone vs gigantenna next time! Or maybe put the Yagi on the drone and compare the range.
Bigger is not always better with antennas. ADSB runs at 1090mhz which means the full wavelength is just over 5 inches. Anything more than that will offset the resonant frequency and negatively effect reception.
"I have a knife"
Dats not a knife
You can't have such tv shows in France
dude you are swamping the sdr dongle ..rtl sdr dongles have no filtering or band pass..you are so close to that microwave tower it will kill the dongle :)
Agree. KV4VN
9:55 worlds shortest pre-flight check list lolzzzzzz ;-)
Such a pity that this turned out to just be an advert
They are flying into the path of those microwaves......of course they are going to have interference
even if you guys are far from 2.4ghz but look at your surroundings .. RFI ruins your project.. just my 2 cents. but i like your hobby..
She likes it when he eats pineapple 🍍😁👅
tee allowed you to send to file and stdout where was I 8 years ago 😅
Keep it simple, hot air balloon / large helium balloon and string to wind it back to earth
extraverts.. got a love'm lol
i need some way to get atlest 300 miles range on a drone and on video can some 1 please help me ?
+luis morel Ask the Federal Communications Commission or the Federal Aviation Administration. I am sure they would like to help you into a prison cell.
well the reason i need this is due to the reason that my cuntry has only 1 search and rescue plane and it was being fix when 1 of my friends boats went down and he drownd now my goal is to build this not to go high up but to go long distance to help as a voluntery helper in search and rescue where i live its a small island with alot of boating going on alot of ppl drown every week here and i want to try and help how ever i can to try and provent this and get erly help to them
+luis morel that´s a very good idea, I have also tough about a search and rescue drone (most likely search only but you got the point).
Its quite difficult to get 300 mile range on a budget but nothing is impossible.
from my research I found that people have used wifi networks to communicate with a ardupilot or a pixhawk board with some sort of serial to ethernet adapter and used ip cameras for live video feed. (there is a pretty good video on youtube with a guy that used a ubiquiti nanostation to do that but I can't find it anywhere) but you could use the same principle of a network encapsulation and use a backhaul radio like the ubiquiti rocket m (specially the 900mhz version) and high gain antennas and a antenna tracker for the base station. if you want to talk more about that idea please PM me on google+ or youtube I´d love to help you out and a lot of other people. specially if the project is replicable for other places like poor countries.
btw what country do you live in ?
yes
I think you guys might have spent a bit to long on radios, I personally don't find it as interesting as what you guys have previously done
please help me make a search and rescue drone :(
+luis morel Flir One