Author Topic: Your own aircraft Radar System for less than $20.00 and improved antenna.  (Read 89697 times)

Offline av8tor172

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Just another odd-ball project idea served up for you from a certifiable oddball.

You're oddball idea made me think (they call it brainstorming!) but yes, so you don't have to worry about cabling getting tangled up by the rotation of the antenna just mount the entire dongle/Raspberry on the antenna itself. Since in my example I get the data from the Raspberry via wifi there are no network wires, the entire dongle, Raspberry and wifi is on the rotating antenna.  Next is power, a battery pack with 4 D-cells should work......  how's that for an oddball idea.

George
www.MilAirComms.com

Offline InterpreDemon

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You don't want to be climbing up on the roof to change the batteries, but some of those radome units use slip rings and have electronics in rotation, so you could do that. On the non-radome unit like I had you could probably remove the antenna bar and make a parabolic reflector that rotates around a fixed whip. You'll note on the attached photo, the radiating element (left of red line) is just a stub that is fixed in the center of rotation and the antenna (which is just a 4' long waveguide with slots and baffles that bolts over it) rotates around it. You would just extend that radiator to 2.7" long for 1090, make a PVC pipe and cap that fits over that o-ring  you see to protect the whip and internals from the elements, then bolt your parabolic reflector or a corner reflector to a pair of those mounting holes, tilted up ten degrees or so. In fact, if you just made a corner reflector with a flat "base" side on the bottom in addition to the two vertical sides, you would probably get the elevation for planes well above the horizon as well as those on it.

I wonder if I have one of those old heads buried over the garage... I had a couple spare rigs for parts, but I think they went into the dumpster at some point. I know I still have a drive motor. Could be a very interesting project.

Offline Marty Becker

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I received my Raspberry Pi today.  Still waiting for my doggle to arrive.  I followed George's article documenting the initial RPi setup. http://www.milaircomms.com/raspberry_pi_setup.html  Everything worked just fine. 

After setting up the Wifi connection via a wired connection with wicd-curses, I disconnect the wired connection and can stay connected to the Wifi.  However, I have one problem. Once I reboot the RPi, the Wifi connection is not established anymore.  Using "Fing" on my iPad to look at what is connected to my wifi network, I can see that the RPi connection is dropped when I reboot the RPI and it never connects again.  Any ideas?  I am trying to google for some ideas too.

Thanks!

Offline av8tor172

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Here is what I found on my system.

Once you get wicd-curses to connect to the Wifi the first time, removed your ethernet cable from the pi.  Then everytime I reboot the Wifi connection is active, I've done this many times without any problems. 

However anytime you reboot the pi with the ethernet cable connected you then have to use wicd-curses to 'connect' to the Wifi.  Took me a few tries to see what was happening, but now that I never reconnect the ethernet cable I've been coming up with the Wifi connection everytime.

If that procedure isn't working for you, I'm not sure what to look at next other than to make sure all the settings in wicd-curses are being remembered during reboot.

George
www.MilAirComms.com

Offline Marty Becker

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George,

I got the Wifi connection working by following the steps on this website: http://www.howtogeek.com/167425/how-to-setup-wi-fi-on-your-raspberry-pi-via-the-command-line

Now the wifi connects after each reboot and I can connect remotely from my Macbook.

I had to add these 5 lines to my /etc/network/interfaces file:

allow-hotplug wlan0
iface wlan0 inet dhcp
wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf
iface default inet dhcp
auto wlan0

and these lines to the /etc/wpa_supplicant/wpa_supplicant.conf file:

network={
ssid="YOURSSID"
psk="YOURPASSWORD"
proto=WPA
key_mgmt=WPA-PSK
pairwise=TKIP
auth_alg=OPEN
}
« Last Edit: April 24, 2014, 10:02:00 PM by Flyingnut »

Offline av8tor172

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I had to add these 5 lines to my /etc/network/interfaces file:

allow-hotplug wlan0
iface wlan0 inet dhcp
wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf
iface default inet dhcp
auto wlan0

and these lines to the /etc/wpa_supplicant/wpa_supplicant.conf file:

network={
ssid="YOURSSID"
psk="YOURPASSWORD"
proto=WPA
key_mgmt=WPA-PSK
pairwise=TKIP
auth_alg=OPEN
}

Thanks for the info.  That does make sense. I guess wicd-curses interface doesn't rewrite those files.  I'll have to play with that this afternoon....all info helps!

George
www.MilAirComms.com

Offline Marty Becker

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George,

With your excellent RPi ADS-B article, I was able to get my RPi and RTL-SDR dongle working and receiving ADS-B data. Some images are attached showing the hardware, my data dump and a pic of the Plane Finder app that shows similar ADS-B data.

Thanks so much for your articles!

Offline RonR

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I am having way too much fun with this...attached pic of adsbscope shows 26 planes...some passing over NYC, some departing and some arriving...I love it...

I modified one of the data files in adsbscope to show some of the relevant VORs and Waypoints...

and then listening to liveatc at the same time, watching the planes turn and/or descend at the same time they are told to by ATC, awesome....

Still using the 6" antenna...waiting for the adapter to arrive.  Should be interesting what happens then  :-D

Ron

Offline Chris Pitre

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Just got into doing using this, I absolutely love it.  Just using one of those RTL-SDR USB dongle from ebay, software is ADSB SCOPE and RTL 1090.  It really does work great.  Now I am experimenting with the antennas...homebrew and discone.

I have seen many aircraft on the screen using KDTW...this goes hand in hand with monitoring aviation in my opinion.


Chris

VE3CTP / VE3ZO


Offline av8tor172

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Just got into doing using this, I absolutely love it.  Just using one of those RTL-SDR USB dongle from ebay, software is ADSB SCOPE and RTL 1090.  It really does work great.  Now I am experimenting with the antennas...homebrew and discone.
Chris
VE3CTP / VE3ZO

Chris you might want check my article on an antenna I built that was a big improvement:
http://milaircomms.com/adsb_antenna.html

I first started with the little 6" antenna that came with the dongle, that worked ok inside the house (actually surprised me!). Then hooked it up to a scanner antenna in the attic, that was a nice improvement.  Then I built the antenna I outlined in my article and wow, still inside my attic with tons of wiring around and less than 20' AGL (same as MSL here in Florida!) I have had as many as 100 planes on the display.

These things sure are a lot of fun!
George
www.MilAirComms.com

Offline InterpreDemon

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Whipped up many of those collinears over the years, unless you have a good grid dipper for 1090 you probably won't get enough precision in the cutting to get the +6 or +9 db gain out of an 8 or 16 element, and the BW gets narrower the more elements you've got, meaning your match could be well off target. HOWEVER, if you get your hands on some plain old RG-11, RG-8, RG-9 or RG-213/214 (non-foam) with copper conductor and shield you can broaden the BW and it is much easier to solder than trying to solder aluminum and messing around with foil. I also note that in the original construction article he uses a 50 or 75 ohm terminator at the end of a 1/2 wave element... even though it will work, that is not correct. What you do is add one more coax element (to the four, eight or sixteen 1/2 wave stack) that is 1/4 wave instead of 1/2 wave and add a 1/4 wave (in air) radiator to the end of that, which will provide the proper radiation resistance as well as provide a DC circuit to ground to protect against static. You short the end of the last (now 1/4 wave) element, and the radiator is attached to the short... meaning you simply extend the center conductor of the last element by 1/4 wave and short the shield at its base. With a little loop on the end of the radiator you can hang it with some fishing line. You can also decouple the feed line and improve the match by adding another 1/4 wave coax section below the first 1/2 wave element feed point with either some radials around its base or a shorting stub from the bottom of its shield ("it being the 1/4 wave section) to point on the feed line shield 1/4 wave in air below.

But the most important thing is to check the actual velocity factor of the cable you are using. Do not use generic or manufacturers' specifications, my own experience is that they simply are not good enough when working at UHF and above, in fact rarely at VHF. Cable changes over time and from batch to batch, and the higher the frequency the more critical these changes become. This can be done either with a grid dipper or an analyzer like an MFJ 259. It is not necessary to dip the 1/2 wave elements at 1090 (though nice if you can), just get the actual, measured wavelength at 136.25 for your chunk of coax and divide by 16 to get the length of your 1/2 wave elements.

A quick search found this article which is about as good as any on the subject...

http://www.angelfire.com/extreme/sideband/collinear.html

HAMs have been building these for decades, in fact I knew guys who made them to work 1296 back in the early 70's when very few had the equipment, skill or technology to get "up" there, let alone buy any antennas on the market. They'd just string them together and hang them from an outrigger on their towers.

Offline Chris Pitre

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Update...

I switched software to planeplotter...as for the antenna, I made one of the colinear antennas...now just have to wait for the snow to stop falling and get it on the roof.

I will post an update when this happens and share my results.

I am having way too much fun withthis stuff.


Offline Marty Becker

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I received my userId/password from PlaneFinder.net and was able to install NodeJS and their PF Client software on my Raspberry Pi.  The attachment shows my local data that is being fed to Plane Finder

Offline RonR

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One of the reasons I've stuck with adsbscope thus far is that I've found it easy to modify some of the files to add an airport or two and also add a few of the critical waypoints and VORs in my area (NYC).  I personally prefer not to have a map in the background; I feel it clutters up the display too much.  Instead, I like just the outline of the landmasses and together with the waypoints I added, it looks to some extent like a scope. 

I've also so far added about 350 new aircraft types to the existing list.  If there was a blank space for the type aircraft listed in the adsbscope table, I did a little research and added the information to the corresponding file.

Still waiting for that cable adapter so I can connect to an outside antenna...

Ron

Offline av8tor172

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One of the reasons I've stuck with adsbscope thus far is that I've found it easy to modify some of the files to add an airport or two and also add a few of the critical waypoints and VORs in my area (NYC).  I personally prefer not to have a map in the background; I feel it clutters up the display too much.  Instead, I like just the outline of the landmasses and together with the waypoints I added, it looks to some extent like a scope.

Ron - Have you downloaded the new version of RTL1090?  I believe its called Beta Version 3.  Been running it now for a month.  It has a built in scope that you might like.  I've attached pictures of the built in scope.
George
www.MilAirComms.com

Offline Marty Becker

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I just added an article on how you can double your reciption range of the original system with a better antenna. It took me about an hour to build, test and install with a total cost of $7.00. You can view the article including pictures here: http://milaircomms.com/adsb_antenna.html

I built an 8-segment antenna today.  Much better coverage, even with it hanging in a window.

Offline RonR

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Ron - Have you downloaded the new version of RTL1090?  I believe its called Beta Version 3.  Been running it now for a month.  It has a built in scope that you might like.  I've attached pictures of the built in scope.
George
www.MilAirComms.com

Hey George,

Just gave the new version of RTL1090 a try.  It's nice!  In addition to the executable file, I also placed the three *.dat files into the SDSSHARP folder so that VORs and airports show up on the "scope".  Here's a screenshot...

Ron


Offline Fokker70

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You guys have sold me, I'm going to give this a try and see what I get in northwest burbs of ATL

Offline Rick108

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So... now that we are starting to have various sites sprinkled around the country... how cool would it be to have these different sites all feed their ADS-B data in real time to LiveATC, and have a new wbe page that would combine all the data onto one big map that could be panned and zoomed.  The feed bandwidth should be much lower than an audio feed...  Hmmmm...  :evil:

Offline RonR

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For those who are using ADSBScope, I've updated the aircraft file (icao24plus.txt) over the past several weeks to add aircraft that were not defined in the original file.  The attached file adds some 900+ aircraft that I have seen in the NYC area with new ones appearing every day.  Simply replace the existing file in the "extra" folder with this one.  You may want to backup the original file in case there are issues with the new file.  But it works on my setup without any issues so feel free to use this updated file if you like.

Ron


Offline mindlesstux

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For those running dump1090 on PIs, there is a random collection of people pushing their data to SDRsharp.  This data is visable (sometimes, when the plane count is not to high for the host) at http://adsb.rtlsdr.org

You can also reverse the streaming of data down to a device of your own, which I do and host a modified dump1090 that is in net only mode with larger buffers and modified webgui.  My cached copy can be watched at http://adsb.mindlesstux.com/


To push to SDRsharp, use the below script and launch via 'screen -dmS pushSDRsharp ./pushSDRsharp.sh'

pushSDRsharp.sh
Code: [Select]
#!/bin/bash -x

while true;
do
echo "starting the NC | SOCAT"
nc localhost 30002 | socat -u -T10 - TCP4:sdrsharp.com:47806
sleep 5
done

It uses about 1-4kb/sec from my findings going out.

*edit*
After work i'll post shots of my little Pi setup too
*/edit*
« Last Edit: May 05, 2014, 11:45:34 AM by mindlesstux »