{"id":4923,"date":"2016-09-24T15:42:39","date_gmt":"2016-09-24T14:42:39","guid":{"rendered":"https:\/\/stevepedwards.today\/DebianAdmin\/?p=4923"},"modified":"2023-10-28T23:12:44","modified_gmt":"2023-10-28T22:12:44","slug":"intro-to-software-defined-radio-fm-stations-and-tracking-aircraft","status":"publish","type":"post","link":"https:\/\/stevepedwards.today\/DebianAdmin\/intro-to-software-defined-radio-fm-stations-and-tracking-aircraft\/","title":{"rendered":"Intro to Software Defined Radio – FM Stations and Tracking Aircraft"},"content":{"rendered":"
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Sept 2017: Seems you need hassle sufferance for a google API key to view gmaps in dump1090 - if it wasn't bad enough with Windows dictatorship for the last 30 years, now you have to Planetary Wide Big Brother with Google and its Loon Balloons ...yet another control freak dictatorship under the guise of benevolence......you'll just end up locked out of everything unless you conform to the Swastika's Surveillance Ts+Cs...good luck with feeding yourself with digital currency only and no job...!<\/p>\n

Alternative is PiAware - really easy to setup:<\/p>\n

https:\/\/uk.flightaware.com\/adsb\/piaware\/install<\/a><\/span><\/p>\n

Setup an account and see your own data on their map, with loads of data you didn't get with dump1090 Gmaps - cool. The only thing from below you still need to do from the old dump1090 info below is blacklist the default dvb driver:<\/p>\n

sudo vi \/etc\/modprobe.d\/blacklist.conf<\/span><\/p>\n

blacklist dvb_usb_rtl28xxu<\/span><\/p>\n

Once running and account setup, claim the device:<\/p>\n

https:\/\/uk.flightaware.com\/adsb\/piaware\/claim<\/a><\/span><\/p>\n

\"\"<\/a><\/p>\n

--<\/p>\n

I have wanted to get viewing local aircraft via SDR\u00a0going for a while after buying a pretty good RTLSDR unit with 27cm\u00a0aerial and 3m RG174 coax lead from Ebay for \u00a326 a while back. I screwed an iron washer to the roof so the magnet would stick, and it didn't blow off on a very windy day! (Yet...)<\/p>\n

\"rtlsdr.png\"<\/a><\/p>\n

\"aerial.png\"<\/a><\/p>\n

If I'd known how easy it is to see aircraft by finding the right tutorials and not being pedantically stuck on using only SDR software that is in the linux repos (not much!), I'd have done it back in June.<\/p>\n

For a background on SDR see:<\/p>\n

https:\/\/www.irrational.net\/2012\/08\/06\/tracking-planes-for-20-or-less\/<\/p>\n

https:\/\/landoflinux.com\/linux_sdr_adsb_gqrx_radio.html<\/span><\/a><\/p>\n

Viewing aircraft similarly as on<\/p>\n

https:\/\/www.flightradar24.com\/\u00a0<\/a><\/span><\/p>\n

https:\/\/planefinder.net\/<\/span><\/a><\/p>\n

but for aircraft that only your SDR unit can receive, I found easiest by using dump1090 from github:<\/p>\n

\u00a0git clone https:\/\/github.com\/antirez\/dump1090.git<\/span><\/p>\n

Read the README, and if necessary install the missing files when the compile line complains:<\/p>\n

cd dump1090<\/span><\/p>\n

make<\/span><\/p>\n

complaints..?<\/p>\n

sudo apt-get install librtlsdr-dev\u00a0libusb-1.0-0-dev<\/span><\/p>\n

(for a PI,librtlsdr-dev is not in the repos, so using dpkg -i<\/span> you have to DL then manually install:<\/p>\n

wget\u00a0https:\/\/github.com\/mutability\/librtlsdr\/releases\/download\/v0.5.4_git-1\/librtlsdr0_0.5.4.git-1_armhf.deb<\/a><\/span><\/p>\n

wget\u00a0https:\/\/github.com\/mutability\/librtlsdr\/releases\/download\/v0.5.4_git-1\/librtlsdr-dev_0.5.4.git-1_armhf.deb<\/a><\/span><\/p>\n

dpkg -i librt*deb<\/span><\/p>\n

)<\/p>\n

With those, make should compile the program now:<\/p>\n

make<\/span><\/p>\n

To run it and have the data overlaid via it's local http server on google maps, run:<\/p>\n

sudo .\/dump1090 --interactive --net\u00a0--net-http-port 8080<\/span><\/p>\n

or<\/p>\n

sudo .\/dump1090 --enable-agc --aggressive --net --net-http-port 8080<\/span><\/p>\n

Try combos of those switches too, for max res and a table of planes in the terminal.<\/p>\n

I found it complained about a default dvb driver that had hijacked the unit already so had to be blacklisted for next\u00a0reboot in:<\/p>\n

sudo vi \/etc\/modprobe.d\/blacklist.conf<\/span><\/p>\n

# snd_intel8x0m can interfere with snd_intel8x0, doesn't seem to support much<\/span>
\n# hardware on its own (Ubuntu bug #2011, #6810)<\/span>
\nblacklist snd_intel8x0m<\/span>
\nblacklist dvb_usb_rtl28xxu<\/span><\/strong><\/p>\n

remove the module and try again:<\/p>\n

sudo rmmod dvb_usb_rtl28xxu<\/span><\/p>\n

sudo .\/dump1090 --interactive --net\u00a0--net-http-port 8085<\/span><\/p>\n

you could create an alias of this for login then view from a remote browser e.g.<\/p>\n

alias dump='sudo dump1090\/.\/dump1090 --interactive --net --net-http-port 8085'<\/span><\/p>\n

gmap.html needs to be copied to your home dir also! You won't get the map in your browser else!<\/p>\n

dump<\/span><\/p>\n

This should now show any local aircraft info on the command line, so open a local (or remote) browser and view localhost:8080<\/p>\n

\"screenshot-from-2016-09-24-161624.png\"<\/a><\/p>\n

Once out of range for 60 secs it is removed from the table.<\/p>\n

What amazed me the most was the distance that aircraft signals could be received over - about 60-80 miles or more! And on a cloudy wet day.<\/p>\n

This depends on line of sight of course, as those planes out west from Cornwall aren't so blocked by hills from my location about 10 miles west of Truro on the map so pretty much clear to the sea out west. For scale, Plymouth is about 50 miles away from Truro.<\/p>\n

There are projects for increasing the range using filters and tuned aerials for the 1090 MHz channel (UHF) that these signals are broadcast on. I may experiment now after this success, as I have a soldering iron...<\/p>\n

Info on aircraft radio:<\/p>\n

https:\/\/www.faa.gov\/regulations_policies\/handbooks_manuals\/aircraft\/amt_airframe_handbook\/media\/ama_Ch11.pdf<\/a><\/span><\/p>\n

check p61 for ADBS info.<\/p>\n

\"ADS-B Collision avoidance is a significant part of the FAA,s NextGen plan for transforming the National Airspace System (NAS). Increasing the number of aircraft using the same quantity of airspace and ground facilities requires the implementation of new technologies to maintain a high level of performance and safety. The successful proliferation of global navigation satellite systems (GNSS), such as GPS, has led to the development of a collision avoidance system 11-61 ADS-B signal ADS-B signal Ground transceiver Conventional data networks GNSS position data Aircraft broadcast position, Altitude, Speed, etc. Figure 11-136. ADS-B OUT uses satellites to identify the position aircraft. This position is then broadcast to other aircraft and to ground stations along with other flight status information. Figure 11-135. Low power requirements allow remote ADS-B stations with only solar or propane support. This is not possible with ground radar due to high power demands which inhibit remote area radar coverage for air traffic purposes. known as automatic dependant surveillance broadcast (ADS-B). ADS-B is an integral part of NextGen program. The implementation of its ground and airborne infrastructure is currently underway. ADS-B is active in parts of the United States and around the world.\"<\/em><\/span><\/p>\n

https:\/\/www.aviationpros.com\/article\/10389097\/aircraft-communications<\/span><\/a><\/p>\n

It would be nice to be able to hear audio transmissions too but these are on a range of frequencies dependent on civil aviation band usage e.g.<\/p>\n

https:\/\/www.smeter.net\/spectrum\/aviation.php<\/a><\/span><\/p>\n

https:\/\/www.jneuhaus.com\/fccindex\/aviation.html<\/span><\/a><\/p>\n

Unless you live near an airport, you are unlikely to hear much chat anyway.<\/p>\n

High Frequency Aviation Bands<\/strong><\/p>\n\n\n\n\n\n\n\n\n
Frequency Band<\/th>\nAllocation<\/th>\nSLC Receiver
\nReceivable<\/th>\n<\/tr>\n
2850-
\n3155 kHz<\/td>\n		Aviation (2850 to 3000 portion is MF)<\/td>\nYes<\/td>\n<\/tr>\n
3400-
\n3500 kHz<\/td>\n		Aviation SSB (3 KHz Channel spacing)<\/td>\nYes<\/td>\n<\/tr>\n
4650-
\n4750 kHz<\/td>\n		Aviation<\/td>\nYes<\/td>\n<\/tr>\n
5450-
\n5730 kHz<\/td>\n		Aviation SSB (3 KHz Channel spacing)<\/td>\nYes<\/td>\n<\/tr>\n
6525-
\n6765 kHz<\/td>\n		Aviation<\/td>\nYes<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\"freqs.png\"<\/a><\/p>\n

If you don't have an aerial, make one\u00a0- this is a half wavelength aerial for resonance of a 27.5cm wave.<\/p>\n

\"As a result, an antenna that is half the<\/span><\/em>
\nwavelength of the corresponding AC frequency is able to<\/span><\/em>
\nallow full voltage and full current flow for the positive phase<\/span><\/em>
\nof the AC signal in one direction. The negative phase of<\/span><\/em>
\nthe full AC sign wave is accommodated by the voltage and<\/span><\/em>
\ncurrent simply changing direction in the conductor. Thus, the<\/span><\/em>
\napplied AC frequency flows through its entire wavelength,<\/span><\/em>
\nfirst in one direction and then in the other. This produces the<\/span><\/em>
\nstrongest signal to be radiated by the transmitting antenna. It<\/span><\/em>
\nalso facilitates capture of the wave and maximum induced<\/span><\/em>
\nvoltage in the receiving antenna.\u00a0For optimum performance, the
\nimpedance of the transmission line should be equal to the
\nimpedance of the antenna. In aviation antenna applications,
\nthis is often approximately 50 ohms.\u00a0<\/span><\/em>\"<\/p>\n

\"halfwave.png\"<\/a><\/p>\n

https:\/\/antirez.com\/news\/46<\/span><\/a><\/p>\n

\"1090_antenna_1.png\"<\/a><\/p>\n

c=fw<\/p>\n

The Megas cancel so you get:<\/p>\n

300\u00a0\/ 1090 =\u00a00.275m or wavelength of 27.5cm. From below, the aerial needs to be less than 1\/2 this to be tuned to this frequency.<\/p>\n

Electrical solid earth wire should do, soldered to RG6 coax.<\/p>\n

\"A formula can be used to find the ideal length of a half<\/span><\/em>
\nwavelength antenna required for a particular frequency as<\/span><\/em>
\nfollows:\u00a0Antenna Length (feet) = 468 \/\u00a0F MHz.\u00a0It takes into account the dielectric effect of the air at\u00a0the end of an antenna that effectively shortens the length of\u00a0the conductor required.<\/span><\/em>\"<\/p>\n

So that equation is saying that an aerial of length 0.429ft or 12.192cm is ok for 1090 MHz?<\/p>\n

Just to give some distance perspective:<\/p>\n

\"flights.png\"<\/a><\/p>\n

41000ft \u00a0(highest I've seen yet) is\u00a07.765 miles high (1760 yards in a mile, 3ft to a yard for the youngsters), and the furthest away on a clear day is about 150 miles away here, but you may not get full signal decodes:<\/p>\n

\"150.png\"<\/a><\/p>\n

You can also register with some sites to feed them data in return for their premium services, no registration fee or their professional software.<\/p>\n

If you want more info on a plane, just google it's reg number or view it on one of the main flight tracker sites above e.g<\/p>\n

IOS238<\/p>\n

\"ios238.png\"<\/a><\/p>\n

If you want to listen to FM radio on your SDR unit, install:<\/p>\n

sudo apt-get install gqrx-sdr\u00a0rtl-sdr<\/span><\/p>\n

Run it and turn it on:<\/p>\n

sudo gqrx<\/span><\/p>\n

I found it complained about a default dvb driver that had hijacked the unit so had to be blacklisted on reboot in:<\/p>\n

sudo vi \/etc\/modprobe.d\/blacklist.conf<\/span><\/p>\n

# snd_intel8x0m can interfere with snd_intel8x0, doesn't seem to support much<\/span>
\n# hardware on its own (Ubuntu bug #2011, #6810)<\/span>
\nblacklist snd_intel8x0m<\/span>
\nblacklist dvb_usb_rtl28xxu<\/span><\/strong><\/p>\n

This allows gqrx to run the SDR unit - ignore the settings complaint, click no to edit - using the FM stereo dropdown I clearly picked up local radio:<\/p>\n

\"107.png\"<\/a><\/p>\n

And just to scare the shit out of you re the insecure future of this technology...!<\/p>\n