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Air Traffic Monitoring => Listener Forum => Topic started by: av8tor172 on February 20, 2014, 10:28:55 AM

Title: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: av8tor172 on February 20, 2014, 10:28:55 AM
In October 2013 I wrote an article on how You Can Build Your Own Aircraft Radar System for $20.00, see:
http://milaircomms.com/adsb_dongle_aircraft_radar.html

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

Enjoy,
George
www.MilAirComms.com
Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: av8tor172 on February 24, 2014, 08:01:35 PM
I Got My SDR Dongle and Raspberry Pi computer to successfully see Mode-S data on1090 MHz

I recently got a Raspberry Pi Computer, about the size of a credit-card and runs Linux.  I wanted to make use of it somehow in the scanner/aircraft monitoring hobby.

Today I had success in connecting a cheap $20.00 TV Dongle and a Wireless Wifi adapter to the USB ports of the Raspberry Pi Computer and am now able to log into this little self-contained unit from any wifi device and see decoded Mode-S data!  Ok, yes I'm a total geek here! What's cool is this is almost like a self-contained aircraft radar system no larger than a TV Remote Control!

I wrote up an article complete with pictures which you can find here:
http://milaircomms.com/adsb_dongle_raspberry_pi.html

I hope to hear from others who might try this project or come up with other ideas for using the Pi computer in the scanning hobby.

Enjoy
George
www.MilAirComms.com
Title: Re:
Post by: RonR on February 25, 2014, 07:31:20 AM
My TV dongle is a n the way to me...I'll let u know how it goes! I cant wait to see what I can see from long island :)

Ron

Sent from my SGH-M919 using Tapatalk
Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: av8tor172 on February 25, 2014, 10:13:51 AM
If you view the original article http://milaircomms.com/adsb_dongle_aircraft_radar.html and scroll to the bottom you'll see what NYC area looks like.   Shortly after I wrote the article one of my readers put together the system and was on a business trip to New York City.

With the little antenna that comes with the Dongle he captured what you see the picture on my website is what he was looking at in his motel room......you should have a ton of fun....

George
www.MilAirComms.com
Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: RonR on February 27, 2014, 01:20:05 PM
Hey George, got my dongle today and plugged it in right away.  My first shot at this revealed this picture using the little 6" antenna!  Great stuff!

Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: av8tor172 on February 27, 2014, 08:27:45 PM
Super, glad to hear it. 

I had some success today as well.  I hooked that cheap TV dongle up to a Raspberry Pi computer and using the Raspberry's WiFi connection am able to stream audio to the internet!  I have it up and running now, you can see pictures and click on the live link to hear it. The only wire connected to the system is the power cord!  Still have work to do, but pretty good for 1st try.  Just as a test its broadcasting NOAA weather radio just so people can get an idea it really works.  I wrote a howto article with pictures here:
http://milaircomms.com/raspberry_pi_dongle_streaming.html

Keep playing, these cheap radios and computers are fun
George
www.MilAirComms.com
Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: RonR on February 28, 2014, 12:02:33 PM
Hi again George,

Finally had a moment to download and get adsbScope to work!  I find myself sitting and staring at the "scope" watching everything that is happening around here.  It's hard to take my eyes off of it!  I've attached a screenshot from about a half hour ago.  Not bad using the little 6" antenna.  This antenna is currently sitting on a south facing window sill.  Can't wait to see what happens when I use a better antenna.  I'll let you know how that goes when I get to it!  Thanks for making all this information available!
Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: av8tor172 on February 28, 2014, 01:23:24 PM
Cool, looks like you're having fun!  Did you see my article on building a better ADSB Mode-S antenna? If not here it is:
http://milaircomms.com/adsb_antenna.html

The antenna was easy to build and cheap.  In fact if you have an RG-6 TV Cable jumper laying around the house you're not using, that is all you need to build the antenna.

When I originally got the system working with the 6" antenna, I then was running it for months with a normal scanner antenna in the attic, that was a big improvement.  Then I bought the Mode-S antenna.  Wow, another major improvement.

I see you're still using ADSBScope for your display.  After I wrote the original article you read, I then started using Virtual Radar (http://www.virtualradarserver.co.uk/). I like VR much better as it logs all the Mode-S data to a database you can look at later.  It also allows you to run a report on just Military Mode-S hits.  Every morning when I get up I always 1)Check my Bank Accounts, and 2)See how many Military Mode-s hits for past day, I have my priorities LOL.

Have fun
George
www.MilAirComms.com
Title: Drunk Pilot caught on ADS-B? You be the judge
Post by: av8tor172 on February 28, 2014, 02:50:13 PM
I Was just looking at my Mode-S ADS-B map and saw something I've never seen before.

Ok I've seen some funny looking holding patterns, but I've never seen someone doing s-turns while enroute at 9500'.

Here's a screen capture of my display:
http://milaircomms.com/images/drunkpilot.jpg and I've attached the picture to this message.

Drunk? You be the judge.
George
www.MilAirComms.com
Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: RonR on March 01, 2014, 07:18:01 AM
Hey George,

Got a question: have a look at the attached picture.  There are a lot of entries that seem to be meaningless, namely all those that start with "C".  Any idea what that's all about?  It's clear they're not real transponder signals, at least as far as I can tell.  A few minutes later, all that disappears.  Is it possible I'm receiving sporadic transponder signals from aircraft on the ground at JFK (25 miles away)?  ADSBScope lists registration numbers for some of these signals and flightaware tells me they are aircraft taxing on the ground at JFK.  That just doesn't seem likely...Thanks  :-)

Ron
Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: av8tor172 on March 01, 2014, 08:31:37 AM
Wow, I've never seen that on my RTL1090 display.

One think you need to remember is that if you're looking at FlightAware, they data is delayed 5 minutes.  FlightAware says they're on the ground at JFK however in real-time (as your RTL1090 will display) they could already be in the air.

If you figure out the C code let us know.  I'll do the same if I see it while searching the net.

Thanks
George
www.MilAirComms.com
Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: RonR on March 01, 2014, 10:05:22 AM
I forgot to mention that some of those ground signals include lat/long coordinates and actually show up on adsbscope. Can that be a false signal? Doesn't sound like it to me. And the fact that the aircraft registration numbers next to these weird signals represent an actual flight, I believe they are real signals from aircraft on the ground. The question is, why is it so interrmitent? One moment it's there, the next it's gone. I might have the answer: could these ground transponder signals be reflecting off of airborne aircraft passing close by? That would explain why it's there one second and gone the next...adsb scope even says they're on the ground so what else could it be? What do you think?
Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: RonR on March 01, 2014, 10:47:36 AM
And here's a screenshot of adsbscope showing a JetBlue flight (N794JB) that was on the ground at JFK (JBU2) - it had just landed.  A minute later this signal was gone.  Fascinating, isn't it?  :-D

Ron
Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: Marty Becker on March 01, 2014, 04:05:29 PM
This really sound like a neat project. I must go and read your articles.
Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: av8tor172 on March 01, 2014, 06:24:05 PM
Ground reflections are possible. I know a ham in a condo, he gets on 1296 MHz SSB but to work stations south of him he goes out on this balcony and aims his yagi at a water tower to the north to reflect signal back south.  It works....

George
Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: Marty Becker on March 02, 2014, 01:36:43 PM
George,

I read your articles and really appreciate the time you took to provide these.  I think I am going to give this a try.

I have a question and maybe this is another article.  How would one take the received ads-b data and send it to a host site, such as Host Monster, HostGator, etc?  I can write a php script to recieve the data and insert it into a hosted database, but what is needed to take the gathered data and then call the host site's php script?  I guess it would be different if one would be gathering the data on a PC or a Raspberry Pi.

Thanks!
Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: av8tor172 on March 02, 2014, 03:16:51 PM
DUMP1090 (the adsb program that runs on the Raspberry Pi) is written in C.  So as a quick and dirty setup I would just go into the DUMP1090 "c" code and every time it received a new mode-s message have the c code send this to a website/php as a long URL.

Have a webpage on your gator host (or who ever you use, I use Hostway, been there for 13 years and love them). Call the PHP something like process_mode_s.php.  Now modify DUMP1090 to then access the website http://www.yourdomain.com/process_mode_s.php?hexcode=AEFF09&altitude=36000&lat=29.32&long=80.23

Then process_mode_s.php can take the variables just to it and store them in an SQL database to be displayed on your website.....quick and dirty but might work.

I never tired to pipe any text from DUMP1090 to a file, might look into that too. Kinda just thinking out loud and brainstorming. Tell me more of what you would like to do with the data....sounds interesting as I do a ton of PHP and SQL stuff with my website.  Heck, most of the .html files are actually generated by PHP code...

George
www.MilAirComms.com
Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: Marty Becker on March 02, 2014, 04:36:39 PM
George,

Thank you for the Dump1090 suggestion for sending the data to a host site.  My use would be to use the data on a google map.

I have done this for a flight sim organization and thought I could try it with real ads-b data.  The flight sim scenario uses FS2004/FSX and FS Flight Keeper to send a user's flight data to the website. The data is received via a php script that stores it in a MySQL database.  Other scripts pull the realtime flight sim data and plot it on a google map.  Really no different than what Plane Finder or FlightRadar does.

Thanks!
Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: RonR on March 02, 2014, 06:34:12 PM
Hey George,

Here's a question for you: if you start SDS# and then adjust the RF Gain within that program through the Configure button, is that setting saved when you close it out and start up RTL1090?  In other words do you happen to know if RTL1090 uses that gain setting?

Ron
Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: RonR on March 02, 2014, 06:53:52 PM
Here are some screen shots from adsbscope since increasing the gain...seems to be much more on the screen than before and they seem to be further away too!...woo hoo!  And this is still with the little 6" antenna!
Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: RonR on March 02, 2014, 10:22:44 PM
So at the moment my little 6" antenna is sitting on a south facing window sill.  Just for kicks and giggles I came up with the idea of taking a sheet of aluminum foil, curving it around the little antenna at about 6" away from the antenna and taping it to the window.  The foil is acting as a reflector.  This seems to have enhanced the range such that I can see planes to the south on the "scope" at a distance of more than 100 NM.  Nice!

Update: I watched two JetBlue flights go southbound.  One at FL380 went out of range at 128 NM and the other at FL360 went out of range at 143 NM.  And a northbound USAirways flight came on the "scope" at 137 NM.  Amazing.
Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: av8tor172 on March 03, 2014, 07:44:51 AM
Hey George,

Here's a question for you: if you start SDS# and then adjust the RF Gain within that program through the Configure button, is that setting saved when you close it out and start up RTL1090?  In other words do you happen to know if RTL1090 uses that gain setting?

Ron

I don't think so, the rf gain is not stored in the dongle. Its stored and remembered by SDRSharp.  When you start dump1090 I believe it uses some default gain value based on what the make and model of dongle can support.  I'm sure there is an option when you start dump1090 to change the gain.  You can try typing "dump1090 --help" for a list of options and how to set them.

George
www.MilAirComms.com
Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: av8tor172 on March 03, 2014, 07:51:57 AM
So at the moment my little 6" antenna is sitting on a south facing window sill.  Just for kicks and giggles I came up with the idea of taking a sheet of aluminum foil, curving it around the little antenna at about 6" away from the antenna and taping it to the window.  The foil is acting as a reflector.  This seems to have enhanced the range such that I can see planes to the south on the "scope" at a distance of more than 100 NM.  Nice!

Update: I watched two JetBlue flights go southbound.  One at FL380 went out of range at 128 NM and the other at FL360 went out of range at 143 NM.  And a northbound USAirways flight came on the "scope" at 137 NM.  Amazing.

Here's a thought for you.  Find a UHF TV antenna, possibly one with the mesh parabolic reflector on the back, mount that on a mast and turn the mast with some low speed motor. Since the signal on the various ADSB software will still display a plane 5 minutes after signal drop the fact your antenna is turning lets say 1 RPM you shouldn't have dropouts when the antenna is in other directions during its rotation. Oh, did I just describe the transponder interrogator antenna for a poor mans apartment LOL....it might work to get good signals from all directions.

George
www.MilAirComms.com
Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: RonR on March 03, 2014, 10:26:14 AM
Well, I just watched a JetBlue flight go southbound out of JFK.  He dropped off the "scope" at 169 NM.  Wow.  You can see it in the attached pic.  The second pic is of my homemade reflector  :-)

I actually have a long-range UHF TV antenna mounted on the roof on a rotor :)  I will definitely have to give that a try!  I'm just waiting for my antenna adapter to get here.  Thanks for that idea.
Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: InterpreDemon on March 03, 2014, 04:48:20 PM
If it were me (and it might be in due time), following George's suggestion for slow rotation I would see if I could find an old Raytheon Pathfinder 2500 or 2600 marine radar scan head like I used to have on my boat, or the Furuno equivalent from the early 80's. The scan head has plenty of real estate in it once you remove the magnetron and related electronics, and the drive motor could be replaced with something much slower or driven at lower voltage (they had 12 & 24vdc models). The rotating antenna is fed via central waveguide, meaning it simply rotates around the fixed waveguide, and you could just put your dongle below and let the motor spin the head around above it. I seem to recall they were s-band rigs (2-4 gHz) but I think the gain and directivity of the array would probably more than offset any wavelength dependent characteristics. Mine was a 2600, which had 50mi range, primarily a function of transmit power, but as a receiver it should easily get those ADS signals out to the radio horizon. Could probably get one of them out of a dumpster at a marina or from some old codger who repairs antique marine electronics for free. If neighbors ask about that thing rotating on the top of your house, just tell them you might need to move at night. Of course you could always do the same thing with a domed unit because they probably have a similar internal setup. The great thing is that it's already weatherproof and could contain everything you need including the PI.

Just another odd-ball project idea served up for you from a certifiable oddball.
Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: av8tor172 on March 03, 2014, 06:39:03 PM

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
Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: InterpreDemon on March 03, 2014, 07:16:54 PM
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.
Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: Marty Becker on March 05, 2014, 07:16:37 PM
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!
Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: av8tor172 on March 06, 2014, 07:47:54 AM
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
Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: Marty Becker on March 06, 2014, 07:37:39 PM
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
}
Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: av8tor172 on March 07, 2014, 07:51:46 AM
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
Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: Marty Becker on March 08, 2014, 04:05:16 PM
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!
Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: RonR on March 08, 2014, 06:41:07 PM
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
Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: Chris Pitre on March 09, 2014, 03:11:19 PM
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

Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: av8tor172 on March 09, 2014, 06:23:34 PM
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
Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: InterpreDemon on March 09, 2014, 08:05:52 PM
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.
Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: Chris Pitre on March 11, 2014, 12:53:30 PM
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.

Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: Marty Becker on March 12, 2014, 04:38:20 PM
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
Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: RonR on March 13, 2014, 09:31:05 PM
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
Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: av8tor172 on March 14, 2014, 10:36:07 AM
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
Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: Marty Becker on March 16, 2014, 08:27:12 PM
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.
Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: RonR on March 18, 2014, 10:11:25 PM
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

Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: Fokker70 on April 08, 2014, 09:57:27 AM
You guys have sold me, I'm going to give this a try and see what I get in northwest burbs of ATL
Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: Rick108 on April 08, 2014, 11:45:34 AM
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:
Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: RonR on May 05, 2014, 10:16:31 AM
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

Title: Re: Your own aircraft Radar System for less than $20.00 and improved antenna.
Post by: mindlesstux on May 05, 2014, 11:42:48 AM
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*