ADS-B DIY Antenna

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jepolch

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Had some spare time this morning, so I made a quick mock-up of my directional yagi motion rig thing, looks quite nice, reception is not jet optimal, but I'll have to tune yagi elements for that i guess

View attachment 1336

Edit: here a nice combined view with virtual radar for both receivers:
View attachment 1337

Right know I'm thinking of ways to combine the data from both receivers in a different way so I can use it on my server-hosted control center, but anyone knows if it is possible to host VRS on a web server/host?
I love that Yagi thingy. But I'm curious of it's purpose. Are you planning to use it as a tracking device? What are the antenna elements made of? I like the little bases at the end. Is that from an electronics kit?
 

xforce30164

Active Member
I love that Yagi thingy. But I'm curious of it's purpose. Are you planning to use it as a tracking device? What are the antenna elements made of? I like the little bases at the end. Is that from an electronics kit?
its just oldschool lego (technic). The elements are made of ~2mm diameter solid copper wire, normally used in 230V AC systems in your house.

The tracking base is for now both an easy way to mount it as well as being able to move it. Not sure if I'm going full tracker yet or not. either way, it looks cool IMO :D.

Some military activity in the skies aswell:
military.png


They are probably just doing trainings, I quite often can hear the jet-fighters flying in the area. (Vliegbasis Woensdrecht is somewhat in my range)
 
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ab cd

Senior Member
A question for ab cd I think.
I've been reading about Yagis and dipoles :eek: For vertically polarised signals the antennas have an "up" and a "down" ie the core is to be attached to the element which points up. What is the theory behind this? I've modelled a Yagi with 4nec2 and can't see what difference the orientation has.
No idea! Will have to do some research on it! From where you got this information that core is to be connected to the element pointing up?

It is strange, but for my Dipoles & Franklins, I have always connected core to element pointing up, without any reason, just intuition. May be my "intuition" originated from a Monopole (like those mounted on vehicles or walkie-talkies/hand-helds), where core of coax is ALWAYS connected to the upward pointing Whip, and shield always connected to the vehicle's body.
 
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jepolch

Active Member
In my post #2194 I'm very curious about the differences in the graphs of the dipole and spider. I was hoping someone would comment on why the reception of the dipole is so spiky, while the spider seems smoother. Is the spider more discriminating, or less sensitive?
 

xforce30164

Active Member
In my post #2194 I'm very curious about the differences in the graphs of the dipole and spider. I was hoping someone would comment on why the reception of the dipole is so spiky, while the spider seems smoother. Is the spider more discriminating, or less sensitive?
Do you mean the difference in the peak frequency? as in with the dipole it is more higher peaks closer together whilst with the spider it is just a much cleaner single spike frequency? Lemme see if I can find my books for the antennas course I did iirc the year before this at the TU, I seem to remember something about those frequency spectrum graphs.
 

jepolch

Active Member
Do you mean the difference in the peak frequency? as in with the dipole it is more higher peaks closer together whilst with the spider it is just a much cleaner single spike frequency? Lemme see if I can find my books for the antennas course I did iirc the year before this at the TU, I seem to remember something about those frequency spectrum graphs.
Yeah, I guess that's a better way to say it. The profiles are so different between the two antennas. That may turn out to be the most important discovery of that long experiment.
 

xforce30164

Active Member
Yeah, I guess that's a better way to say it. The profiles are so different between the two antennas. That may turn out to be the most important discovery of that long experiment.
Haven't been able to find the book yet, but I have been able to put the receiver here in Eindhoven one floor higher up, in the attic. (A new housemate moved in that room and he is fine with the pi being there, so I should be getting slightly better range =D )
 

jepolch

Active Member
Haven't been able to find the book yet, but I have been able to put the receiver here in Eindhoven one floor higher up, in the attic. (A new housemate moved in that room and he is fine with the pi being there, so I should be getting slightly better range =D )
That's great. I have considered putting one in my sister's house next time I visit there. She lives near a regional airport and air force base.
 

ab cd

Senior Member
I gave following command to RPi to check my microSD Card:

sudo dmesg |tail

It displayed a long output, the last line was:

[ 12.810139] Adding 102396k swap on /var/swap. Priority:-1 extents:2 across:2134012k SSFS.

Can any one tell me what this means?
 

DougJohnson

New Member
I gave following command to RPi to check my microSD Card:

sudo dmesg |tail

It displayed a long output, the last line was:

[ 12.810139] Adding 102396k swap on /var/swap. Priority:-1 extents:2 across:2134012k SSFS.

Can any one tell me what this means?
According to the man page: http://unixhelp.ed.ac.uk/CGI/man-cgi?dmesg+8

dmesg just prints the boot time messages. By the way, you don't need "sudo" for it. I get the same last line when I run it. I assume it is just showing the amount of paging space being allocated. -- Doug
 

ab cd

Senior Member
According to the man page: http://unixhelp.ed.ac.uk/CGI/man-cgi?dmesg+8

dmesg just prints the boot time messages. By the way, you don't need "sudo" for it. I get the same last line when I run it. I assume it is just showing the amount of paging space being allocated. -- Doug
Thanks. I thought dmesg increases the size of swap.

I now gave following command:
swapon -s

The output was:


Filename.................Type...........Size...............Used.........Priority
/var/swap...............file..............102396..........0............... -1
 

xforce30164

Active Member
Very nice. Are you going to publish this code?
If it is in a more sustainable/releasable way I will. for now I'm trying several methods of grabbing the data/displaying the maps.

one way is that I just display the dump1090 generated html in a html frame.
the other way I'm using right now to combine the data uses another copy of the dump1090 html files and instead of alling the remote urls of the raspberry pi's it calls a phpscript for the json data.

I'm still changing lots of things and testing it. but I'll definately release the code when I got it in a more stable version. :D

edit: some more military activity :p
mil2.png
 
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