Hi all.... So I finally got an opportunity to sit down and see if I could get my feed started. I have a Raspberry Pi 3 B+. I have the SDR dongle hooked up and have flashed the pi with the FlightAware PiAware 3.6.3. I'm still new to all this linux stuff(have used a few times over the years) but I'm stuck now and I cannot get the screen to go forward anymore. Receiver - WARNING: Connected to receiver, but no recent data seen Multilateration - WARNING: No clock synchronization with nearby receivers Why is there no data received? What does the warning for multilateration mean and what do I need to do from here to get the feed working? Once these issues are fixed, how is it that I know it's being fed to adsbexchange? Thanks
Greetings Eric, Since you're not getting ANY data from the receiver, I'd check out the physical layers; power source, rapsi, SDR, filters, coax, antenna. 1. Ensure that everything is connected proper and secure. (no loose cables/connectors; but don't go too tight, this stuff is as fragile as it looks) 2. Review your gain settings for the SDR in dump1090. (turn it up, till you can find a sweet spot with it) 3. Check your antenna positioning. (keep it high in the sky and straight up and down, NO sideways antenna) 4. Confirm the lon and lat settings in both dump1090-fa and mlat-client configs. 5. Troubleshoot on the shell, check for raspi hardware and power issues with the command: dmesg 6. Run dump1090 from the shell in interactive mode with the command: dump1090-fa --interactive --gain 28 (make sure to stop other processes that lock SDR: systemctl stop dump1090-fa.service or service dump1090-fa stop
PART 2 Unless your antenna is inside and you live far far away from the everything you should be able to see some plane data assuming everything is hooked up. If you have any filters or LNAs on the line, remove them for testing to keep things simple. MLAT or multilateration here at adsbX is kind of like a plane data co-op. Multiple receivers running the mlat-client HAVE to hear the signal, then send back the data to adsbx mlat-server. Calculations are made on the mlat-server to estimate the position of aircraft. That being said about MLAT, with out a working receiver there is nothing to send back to the mlat-server for calculations. The dump1090 mlat-server/client is experimental and most times the stuff you will see in the logs are not what you would guess, best to disregard that log for newcomers. If you're on the west coast mlat1/sync1, it has been broken since about 0800 PST today. So even with a functioning receiver you wont see any remote message or positions with mlat until it is fixed. Make sure that your --user in the mlat-client config has ONLY numbers, letters, dashes ( - ) and underscores ( _ ). NO spaces, NO character encoding. This is VERY IMPORTANT to the health of the mlat-server! so like --user ericcpi01 If those things don't help out, I would re flash the pi and make sure nothing was missed on the install or setup. Last I would check that the SDR you are using is not a dud. It's nice to have another dongle you can test with to eliminate that. I have of over a dozen SDRs and only one shipped DOA, but it happens... Good luck and let us know how it goes.
I already reflashed and was even able to get the adsbexchange script to run to push the feed there....so that is running fine, everything checks out....SDR dongle is good, antenna is outside and good. Receiver keeps going back and forth with a warning of connected to receiver but no recent data seen. I'm not seeing anything on the map either. I installed the flightaware 3.6.3 and followed the instructions. Just no data coming in at all it seems. I did not mess with the gain settings, they are default which I believe is 10.
OK....so did a reboot and got a message that 1090 was disconnected, everything connected back up on reboot but still no data being displayed.
With that being said I'm only showing a couple of aircraft. I just looked on the virtual radar and there are a lot of planes in my area but my feed is not seeing them? Perhaps I need to wait and let it digest......but it's not seeing all the aircraft...
The pi 3 b+ is the most power hungry yet, sometimes 2.5A of 5V is barely enough juice. The only things I can think of the top of my head would be to check for power issues. I have seen SDRs act very strange when the pi having power issues. You can log in to the pi with ssh or on the tyy with a keyboard and monitor hooked up. Once logged in type the command: dmesg Look for anything like: Under-voltage detected! (?) Power supplies go bad, so if its an old one perhaps test output with a multi-meter. I'm pretty sure that the system start script for the FA image and the other installers i have seen, run the dump1090 pid as user dump1090 and the group nobody, so unless the user pi has access to the USB dongle you will need to become root. With the root user you have full access and no restrictions (great for troubleshooting, horrible for normal use aka don't run things as root in most cases) On the shell, as the pi user, change to root with the command sudo su - Once you are root try starting dump1090 in interactive mode to see if you can get some more verbose output. If that works you can paste the logs here and it might shed some more light on things. A few questions: 1. Has the SDR you are using now worked and received planes with the current hardware setup? 2. Do you have SDR# or "sdr-radio console V3" so you can test the dongle on your main computer? (if yes, give it a go, SDR# is easier but console is prettier) 3. Can you tell me the type of sdr, coax, filters, amps and antenna you have on the line? 4. Can you paste or screenshot the errors you are seeing now and a reference of what it is, if not clear? ( like: seeing this in my firefox browser --> screenshot-of-error.jpg ) 5. Do you live near an airport or area where you could be very close to something transmitting on 1090mhz? (too much sig = overloaded sdr) I have done a lot of testing with many different SDR dongles and dump1090 settings, never once was "-10" aka auto mode even in top 5 gain setting for max planes, but i don't think that has anything to do with the error you are getting now. If everything else checks out, the path to finding the issues will most certainly be done on the shell. There are many things that play a role is how one of these systems preforms, but even poor conditions you should see some adsb data or at least some preambles when you run it on the command line. Odds are when you log in and start dump1090 on the shell it will tell you exactly what is wrong when it fails.
1. Has the SDR you are using now worked and received planes with the current hardware setup? Yes I have used it with SDR# and with ADSBSCOPE - I plan on ordering a flight aware pro dongle here in just a little while but yes this one is working. 2. Do you have SDR# or "sdr-radio console V3" so you can test the dongle on your main computer? (if yes, give it a go, SDR# is easier but console is prettier) Yes as indicated above it's working 3. Can you tell me the type of sdr, coax, filters, amps and antenna you have on the line? I'd love to but the shell fell off and I don't have the top side of the case but it's just a cheap SDR dongle. Coax is from cable experts and is LMR400 flex 100' ran to a diamond discone at about 30 feet. 4. Can you paste or screenshot the errors you are seeing now and a reference of what it is, if not clear? ( like: seeing this in my firefox browser --> screenshot-of-error.jpg ) Tried to post up a link to screen shot earlier before the first post and it told me I was not allowed to have links like that in my post. 5. Do you live near an airport or area where you could be very close to something transmitting on 1090mhz? (too much sig = overloaded sdr) Yes as a crow flies I'm less than 1/4 mile from KYIP(Willow Run Airport. The next airport is DTX (Detroit Metro airport which is about 14 miles from me)
Data goes from the SDR to the map within a matter of seconds, no digest (adsb data -> ant. -> sdr -> preamble decoded -> related msg decoded -> passes checksum -> dump1090 writes it in json -> seen in browser | all before you can blink an eye) . Tinker with the gain settings some, you might be able to see a few more. Don't let ghosting aka more messages per second fool you at high gain, the most important gauge is aircraft. There is no magic gain setting that works for everyone since RF propagation is influenced by so many factors. Start out low, and work up. 90% of what I have found to be best falls between 16.6 and 42.0 ( LNA setups excluded) Air traffic changes a lot within a 24 hour period. I see between 2 and 200 aircraft depending on the time of day. So if you're an east coaster you are entering the dead hours. Check a 3 day stats screenshot for one of my setups, dead hours are very low traffic:
Is there a way to mess with the gain settings? I tried to gain in the pi but it wont save it, so I tried to change it to 30 in the config but then I got nothing. Right now after setting it back to -10 I'm getting 3 civilian aircraft but adsbexchange virtual radar is showing way more planes in south east lower michigan where I am. I'm not getting that on the feed......so somewhere I think there is still something wrong...
OK....so I zoomed into the map and I got more aircraft. I'm guessing it local area for me here and not the same as with the virtual map........so am I safe to say that the feed is working then? I get more aircraft the more I zoom in. Is there a way to check what I'm actually feeding to adsbexchange? Update, just looked at my feed again and I'm back to no aircraft but there are plenty flying in the area! 2nd UPDATE - Tried to change the gain settings using sudo /etc/default/dump1090-fa and when I change it and restart 1090 it puts it back. I changed it from -10 to 30 but now I cannot get it go lower than 30. I'm tired and I've been at this all day because I don't know linux well and not getting a lot of help. To those of you that have helped thus far, thanks.
Eric, I'm not new to RF, linux, SDRs, adsb; but I am a new poster here, so I have some major latency on sending out the reply from the much needed spam protector! So my messages are not in order with the thread =/. If the processes are running, you see planes on the local pi and you see no error, then things are probably fine. If it breaks again (meaning you see errors or getting 0 msg /sec) log into the pi and post the command line output of starting dump1090 by hand. I'm not the SDR Doctor, but from what you described so far these symptoms still look like physical layer to me. (the power source or the dongle) You can't test the SDR until you get another, but you can rule out bad power to the pi by checking the output of dmesg. (for FA rtl-sdr I like the blues ones better than the orange ones personally) The mlat2/sync2 looks to be functioning properly (that is the server for your region). I don't claim to know the inner working of the mlat-server, but I do know one thing for sure; the mlat-server likes it slow and steady, if you restart dump1090 on the pi a lot the mlat-server will not pick your station to participate in the multilateration process. When you participate in multilateration your local mlat-client will feed the track data back into dump1090, which will then display it on your local map. (more aircraft) I have a receiver station that is about 2 miles from BUR and not too far from VNY, If I have the gain set over 30 the SDR overloads. Other places not so close to airports I can push 42 gain. I'm not 100% sure how to change it on the FA image or with the adsb built one either. Crazy I know, but I use a different image; its most likely going to be in /etc/init.d/dump1090-fa or /etc/defaults/dump1090-fa since I think both still use the old sysV init. To change the gain setting you: log in to the pi, become the root user, edit the config file or init script with vim or nano, restart the service or reboot the pi. I'm sure some of the regulars know that one of the top of their heads and can tell you if those file location are not correct. That LMR400 is the good stuff and those discones are cool too, just not best in slot for 1090 IMO (hope you're earth grounded). I have made a few antennas and purchased a handful too, tested all of em; and nothing touches the 56 inch DPD antenna, but even that little 26 inch FA on amazon will probably do you better than a wideband in the city. I have heard of some folks using discone and other wide-band antennas but it never worked better for me. ( tuned antenna = more aircraft) If you live near an FM transmitter broadcasting over 1k watts (most of us do) then you might want to look into an "fm blocker" or "fm band stopper" filter, and no matter what I would get one of the cylindrical chrome FA adsb filters. (they are on amazon too) I'm sure some of the others here will have tuning tips too, but things tend to move slower on the forums so it might be a bit.
Most rtl SDRs have these supported gain values (29 total and auto gain): 0.0 0.9 1.4 2.7 3.7 7.7 8.7 12.5 14.4 15.7 16.6 19.7 20.7 22.9 25.4 28.0 29.7 32.8 33.8 36.4 37.2 38.6 40.2 42.1 43.4 43.9 44.5 48.0 49.6 and -10 for auto gain. The number you pick for the gain setting should be one of them. If you run the command rtl_test it will show you the supported gain settings for your SDR. The only way I know of to change the gain for dump1090 is to edit the config file or init script (which is then passed to the dump1090-fa binary as a parameter when its started with init) , then restart dump1090 or reboot the pi to apply the change.
rtl_test Found 1 device(s) 0: Generic, RTL2832U, SN: 777711111153705700 Using device 0: Generic RTL2832U usb_claim_interface error -6 Failed to open rtlsdr device #0
thanks for the help. I'll try again tomorrow. Everything you just said was mush to me. I'm not a good user of linux so unfortunately I need my hand help when doing some of these commands.....
discone .. bad ... it's waaaaaay too wide and noisy for ADS-B. I tried with one on my roof with absolutely terrible results. cheap and easy... Coke-tenna http://www.radioforeveryone.com/p/coketenna-easy-cheap-effec.html J-Pole http://www.lll.lu/~edward/edward/adsb/antenna/ADSBantenna.html Co-linear https://www.balarad.net/ Dan and I have been testing a 1090/978 combo antenna for ADS-B, since FA got rid of the 978 capability on their antenna. Custom ADSBx 1090/978 https://store.adsbexchange.com/collections/all
