ADS-B DIY Antenna

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toml

New Member
For benefit of other members, answer to @toml 's question:
The "rtl_test" command will execute only when you stop dump1090, which is using the dongle. When dump1090 is running, the "rtl_test" command gives the response "No Supported devices found"
Thanks for that...I got close to having the RPi working with Dump1090 yesterday but apparently the RPi 1 does not seem to have enough current capacity in its USB port to drive my Nooelec. I will have to get a powered hub...
 

ab cd

Senior Member
When I test an antenna, I use one of my good antennas as reference or benchmark antenna.
I place both the antennas inside my apartment, near a large window, at same location, same height, at a horizontal spacing of about 1 meter.
The height of both antennas above road/ground level is 60 ft / 20 m.
I do NOT use any amplifier with any of the two antennas.


System 1: Benchmark Antenna (Cantenna) > 15 ft / 5m RG6 Coax > F to MCX pigtail > dvb-t dongle #1 > RPi #1

System 2: Antenna Under test > 15 ft / 5m RG6 Coax > F to MCX pigtail > dvb-t dongle #2 > RPi #2


Image 1 of 2 (system 1 - benchmark antenna

collectd-rate-cantenna-04Sep2015.PNG




Image 2 of 2 (system 2 - antenna under test)


collectd-rate-8e coco+capacitor-04Sep2015.PNG
 

kirovoleg

New Member
Hello guys, long time lurker of this thread.

I just wanted to thank you for helping me increase the coverage I get and also my knowledge.

This is my current setup:

1 Raspberry Pi 2 with a powered USB hub and 2 RTL-SDRs. One of the dongles is collecting from a dipole antenna using dump1090-mutability and feeding to FR24, FlightAware and Plane Finder. The other is using an older spider antenna I made for testing with dump1090-mutability feeding with netcat to the first one in order to combine the feeds.
Both antennas are next to each other near a windowed roof. Sadly I have been unable to find an easy way to put them outside since I have a wall that is decreasing my reception to the north.

Dipole:
20150906062204.jpg


I used to have a cantenna made from a peach can which worked quite well, but I`ve moved to a new apartment and could not take it with me.
As can be seen in the following graph, on the 30th I moved to the new location and started using the spider antenna, this increased position reports from 11000 to 16000. Then on the first I built and started using the dipole antenna and a balum which increased the reports to 20000 and finally, on the 3rd of september I combined the two feeds which increased reports to 23000.

Reception:
summary.png
Max range so far has been in the order of 300km to the south, I{ve been trying to buy an amplifier but so far all the electronics stores I've been only have the TV kind.

AB CD, I am interested on plotting some graphs, could you please provide more details on your rrd collectd tool setup?

Regards
 

ab cd

Senior Member
Hello guys, long time lurker of this thread.

I just wanted to thank you for helping me increase the coverage I get and also my knowledge.

This is my current setup:

1 Raspberry Pi 2 with a powered USB hub and 2 RTL-SDRs. One of the dongles is collecting from a dipole antenna using dump1090-mutability and feeding to FR24, FlightAware and Plane Finder. The other is using an older spider antenna I made for testing with dump1090-mutability feeding with netcat to the first one in order to combine the feeds.
Both antennas are next to each other near a windowed roof. Sadly I have been unable to find an easy way to put them outside since I have a wall that is decreasing my reception to the north.

Dipole:
View attachment 2342


I used to have a cantenna made from a peach can which worked quite well, but I`ve moved to a new apartment and could not take it with me.
As can be seen in the following graph, on the 30th I moved to the new location and started using the spider antenna, this increased position reports from 11000 to 16000. Then on the first I built and started using the dipole antenna and a balum which increased the reports to 20000 and finally, on the 3rd of september I combined the two feeds which increased reports to 23000.

Reception:
View attachment 2341
Max range so far has been in the order of 300km to the south, I{ve been trying to buy an amplifier but so far all the electronics stores I've been only have the TV kind.
GREAT! Welcome aboard!

AB CD, I am interested on plotting some graphs, could you please provide more details on your rrd collectd tool setup?

Regards
Please go to this forum which gives details about rrd collectd tool installation:

http://discussions.flightaware.com/ads-b-flight-tracking-f21/system-monitoring-t26999.html

.
 

Oz Wald

New Member
No idea if this is of interest to the group as I can't think of a permanent use for it, but anyway:

Using some bits of plastic electrical trunking and a couple of old bathroom accessory fittings I've made a mobile mast for my car. The idea being to drive out somewhere high (natural or man-made) and see what you get; as I said earlier, time on my hands.

MobileADS-B2.jpg Mobile ADS-B3.jpg

Parked right outside of my house with the 2nd spider I made, and using rtl and adsdscope, it's picking up a radius of about 100nm.
My wife already thinks I'm mental, let's see how she reacts to "Let's go for a little drive."
If I could find a high spot with a SKY wi-fi hotspot I could use Planefinder, but I shan't be holding my breath.
 

kucengemok

Member
No idea if this is of interest to the group as I can't think of a permanent use for it, but anyway:

Using some bits of plastic electrical trunking and a couple of old bathroom accessory fittings I've made a mobile mast for my car. The idea being to drive out somewhere high (natural or man-made) and see what you get; as I said earlier, time on my hands.

View attachment 2346 View attachment 2347

Parked right outside of my house with the 2nd spider I made, and using rtl and adsdscope, it's picking up a radius of about 100nm.
My wife already thinks I'm mental, let's see how she reacts to "Let's go for a little drive."
If I could find a high spot with a SKY wi-fi hotspot I could use Planefinder, but I shan't be holding my breath.
people in ur vicinity will call u nut.......same goes to me when people saw me with the antenna for FR24....
 

airbus340

New Member
I read in another forum about upside down cantenna so I tried it, not much difference.

Got another idea, maybe ab cd can calculate it in the program?
As I now have two identical cantennas I am thinking about stacking them. Should they be side by side or on top of eachother and how far apart should they be?
 

Mukundan

New Member
No idea if this is of interest to the group as I can't think of a permanent use for it, but anyway:

Using some bits of plastic electrical trunking and a couple of old bathroom accessory fittings I've made a mobile mast for my car. The idea being to drive out somewhere high (natural or man-made) and see what you get; as I said earlier, time on my hands.

View attachment 2346 View attachment 2347

Parked right outside of my house with the 2nd spider I made, and using rtl and adsdscope, it's picking up a radius of about 100nm.
My wife already thinks I'm mental, let's see how she reacts to "Let's go for a little drive."
If I could find a high spot with a SKY wi-fi hotspot I could use Planefinder, but I shan't be holding my breath.
No worries... this "wifey" problem is a Universal phenomenon :)
 

Oz Wald

New Member
Thanks Mr. Crow!
crowdamage1.jpg crowdamage2.jpg

We have a family of crows, numbering about 7 living nearby. Every morning, just after dark o'clock, they're up and about doing the "Get orf my land!" business with other crow families.
I don't normally care, but now it's got personal.
The basket aerial wasn't very efficient, getting just over half the "hits" of the whip, but now I've got to go up and retrieve it and straighten the whip on the other one.
 

ab cd

Senior Member
then? put it on the top of the roof?
No, this on roof will not sustain weather & wind. This is for those who use the stock antenna indoors, mostly those who buy the DVB-T dongle for the first time, and dont have any antenna, pigtail, coax etc and use this whip indoors. They can improve performance as shown in my graphic. That is why I started with "If you are using the whip antenna...."
.

Ultimately a better antenna, installed on roof (or if roof installation is not possible, in attic or near a large window) is the solution
 

airbus340

New Member
Now I have completed a 14 days test of cantenna 86x86 mm. The range was about 200nm. This morning I hooked up my 68x68 mm cantenna and after 10 hours it has already passed the 5/8 cantenna in range, s0 68x68 is best.

Same with the number of a/c and message rate, message rate is at least double and when I disconnected the 86 mm cantenna I had 17 a/c on my screen, 10 sec after the 68 mm cantenna started I had 22 a/c.
 

Viss

New Member
In regard to brass tube collinear antenna.
It is my understanding, that velocity factor is what makes it so difficult to build without proper equipment. When I saw shield build out of pipes instead of coaxial cable, I thought it was a perfect opportunity to have the pipe empty (maybe with some small support insert inside) and accept velocity to be 1.0. But it did not happen, everybody inserts foam from the coax cable. Why?
 

Viss

New Member
I want to build a couple of simple antennas, and I have "RTL-SDR Blog R820T2 RTL2832U" dongle. It has SMA connector, which is 50omh.

I am a little bit worried about multiple transitions.
N adapter to hold 2mm wire antenna (50omh)
N-to-F adapter (50-to-75 omh)
RG6 cable, F connectors (75omh)
F-to-SMA pigtail (75-to-50 omh)
Dongle SMA (50omh)
Thus I get 50->75->50 transitions. Should I instead plan on using RG316 and SMA all the way to avoid 75-50 transitions?
But if I will want to use cheap in-line sat amplifies, they all have F connectors, right? Can't decide what should I do.
 

ab cd

Senior Member
I want to build a couple of simple antennas, and I have "RTL-SDR Blog R820T2 RTL2832U" dongle. It has SMA connector, which is 50omh.
As far as I know, the DVB-T dongles have either MCX connector or IEC/DIN connector, not SMA connector.

I am a little bit worried about multiple transitions.
N adapter to hold 2mm wire antenna (50omh)
N-to-F adapter (50-to-75 omh)
RG6 cable, F connectors (75omh)
F-to-SMA pigtail (75-to-50 omh)
Dongle SMA (50omh)
Thus I get 50->75->50 transitions. Should I instead plan on using RG316 and SMA all the way to avoid 75-50 transitions?
But if I will want to use cheap in-line sat amplifies, they all have F connectors, right? Can't decide what should I do.

All adapters are suitable for both 75 and 50 ohms, so there is no 50 to 75 or 75 to 50 ohm transition with adapters.

It is the cables, antenna & receiver which cause transition, and have impedance as follows :
Your antenna is 50 ohms
Your coax RG6 is 75 ohms
Your Pigtail (normally RG174 or RG316) is 50 Ohms
Your DVB-T input is 75 ohms.

Transition 1: from 50 ohm antenna to 75 ohm RG6
Transition 2: from 75 ohm RG6 to 50 ohm RG174/RG316 pigtail
Transition 3: from 50 ohm RG174/RG316 pigtail to 75 ohm DVB-T

Don't worry about these transitions as every one uses this system and it works ok. The reason is that 75 ohm & 50 ohm are not far away and dont pose a big mismatch.

If you are too much concerned, then you can reduce the one transition if you use an antenna of 75 ohm impedance instead of 50 ohm impedance.

you can reduce one more transition if instead of RG174/RG316 pigtail, you use an F-female to MCX-male adaptor shown below, but I wont recommen it as the flexible pigtail prevents the load of heavy RG6 to be transferred to the delicate MCX female socket of DVB-T. Using adapter shown in picture below will remove one transition, but will put DVB-T Dongle to risk of a damaged MCX socket in due course.

F-female to MCX-male.jpg

.
 
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