FlightAware Discussions

Antenna on roof, what cable to use?

I was indeed forwarding port 8080 to the internet. I did that after I forwarded some ports of my IP camera and thought it would be fun to watch the ADS-B data outside of my local network. But honestly; I never used it.

I deleted the forwarding. I’ll probably know in less then 24 hours if it helped…

I will look into PiAware 3; it looks very promising. :smiley:

stanislavpalo130 sells good products, I purchased a small antenna from him last year, and worked as should out of the box.
I have however been using an antenna I made from RG213 as an collinear 1090mhz antenna and works so much better.
I know he has made the one I used obsolete and has redesigned some better ones, but going by the one I purchased I see no problems.
His 60CM Antenna ads-b collinear great gain for usb dongle flightbox looks good for the cost.

Best thing is though, get it up high, mines is still only 10 feet above ground on the back of my house, but the signal bounces off the house behind us.

Behold; the world’s worst soldering job :unamused: :

https://c7.staticflickr.com/9/8898/28402505934_91d624eb88_c.jpg
ADS-B spider antenna by Iemand91, on Flickr

This was my range with the stock antenna; shortened to 67mm:
https://c7.staticflickr.com/9/8386/28402560654_a1381ef61f_c.jpg
Shortened stock antenna by Iemand91, on Flickr

This is my range with the spider:

https://c8.staticflickr.com/9/8057/29022748375_598f3a0202_c.jpg
Spider antenna by Iemand91, on Flickr

Note: antenna is inside, behind a window. It’s now almost directly above my router so the Wifi connection is better then on my first location; behind another window.
Behind that window the reception was somewhat better.
So I’m probably going to set the antenna up behind that first antenna too, to see results from that location.
And just for fun; mount it outside/high up for a day.

Unfortunately my poor old Raspberry Pi (first generation B) barely holds up. FlightAware says CPU load is 95% or more. With the stock antenna this was only happening when the Pi was booting up.
I don’t know if this is because it’s receiving more positions or something else; but it’s not nice.

The spider is now up for almost 24 hours and August 16 isn’t over yet (almost 16:00 here) but total reports is up, total aircraft not so much.
If you want more details; watch this: nl.flightaware.com/adsb/stats/user/Iemand91
Note: on August 11 I disabled port forwarding; since then my setup doesn’t go down anymore.
I installed the spider antenna yesterday afternoon.

Do yourself a favour and upgrade your Pi to a Pi 2 or better, a Pi 3 – your little beastie is out of gas…

With the antenna outside and the better decoders in PiAware 3.0.3, I’d guess your numbers should double, at least.

have fun!

bob k6rtm

Just ordered the Raspberry Pi 3. Should come in tomorrow.

The soldering job was indeed very bad. The entire ring of solder (with the 8 pieces of copper) came of entirely; it just doesn’t stick/melt to the connector.
Now I’m using the stock DVB-T antenna again.

Try this one. No soldering.

GROUNDPLANE ANTENNA MADE OF COAX ONLY - Without SO239 Conctr

For outdoor use, apply hot melt glue or some other glue such as two part epoxy glue (araldite, locktite etc) at the point where radials are inserted into the coax jacket. Take care NOT to apply too much glue, as it can enter the coax and break the connection between radial and coax shield. After the glue dries, check connection from tip of each radials to braid (F connector body) of feed coax by a multi-meter/multi-tester/continuity-tester.

Based on my above design, the antenna in the photo below was recently built (in June 2016) by FR24 forum member FR24-BB8.

Installed the RPi3 yesterday but didn’t work properly. Since green LED wasn’t on I though the MicroSD-card was the culprit. (was also only 4GB)
Got a new 16GB card today, did the necessary things (installed PiAware3, feeders for FR24 and Planefinder) and everything is working fine now.
I tried to dissociate my old feeder from my account (since I won’t be using my old RPi) but it keeps coming back on my account for some reason.

Thanks for the tip but I’m kinda done with building antenna’s that may or may not be better than stock DVB-T antenna. Currently rocking the stock antenna en thinking whether I should build my own collinear, get the Ebay stanislavpalo130 antenna or the FlightAware antenna with or without the FA stick and with or without filter.
The bad thing about all this is that you don’t know what you should get. People get different results and you can’t really test these without buying them.
And buying both antenna’s, stick and filter ánd making my own collinear gets a bit expensive. :wink:

Make your own coaxial collinear (coco). It does not cost more than the cost of one meter of coax , but keep in mind that different people get very different results. Some end up with a good coco, some with coco same as spider, and a large number with a coco worst than spider.

Also try Cantenna. It will cost you almost nothing, just cost of a F barrel connector (less than a $) and an empty can of beer :slight_smile:.

Try the cantenna. It is the best I have tried so far. The hardest part for me was drilling the hole in the bottom of the can since the aluminum can crumples so easy. I started with three cans and ended up with two antennas. I used coax bulkhead connectors from spare wall jacks I had laying around and a short center conductor from bulk RG6. You can cut the can with scissors. Have a Cantenna made in 10 minutes.

Oh, and where do I find the RPi CPU load info?

One of the wonderful things about Linux – a simple question with multiple answers!

From the command line,


17:10 pi@scylla ~ $ uptime
 17:10:58 up 14 days, 23:11,  1 user,  load average: 0.32, 0.30, 0.32

Load average shows the load on the system over various periods of time. My Pi 3 is loafing.

A longer, more complex incantation:


17:10 pi@scylla ~ $ top -n 1 b | head -n 17
top - 17:11:59 up 14 days, 23:12,  1 user,  load average: 0.34, 0.31, 0.32
Tasks: 119 total,   2 running, 117 sleeping,   0 stopped,   0 zombie
%Cpu(s):  6.0 us,  0.8 sy,  0.0 ni, 93.0 id,  0.0 wa,  0.0 hi,  0.2 si,  0.0 st
KiB Mem:    947092 total,   935820 used,    11272 free,    66128 buffers
KiB Swap:        0 total,        0 used,        0 free.   746864 cached Mem

  PID USER      PR  NI    VIRT    RES    SHR S  %CPU %MEM     TIME+ COMMAND
 4254 dump1090  15  -5   32180  14056   2048 R  23.5  1.5 425:11.61 dump1090-fa
 6397 pi        20   0    5048   2428   2140 R  11.7  0.3   0:00.04 top
    1 root      20   0    5420   3924   2740 S   0.0  0.4   1:13.62 systemd
    2 root      20   0       0      0      0 S   0.0  0.0   0:00.25 kthreadd
    3 root      20   0       0      0      0 S   0.0  0.0   5:34.02 ksoftirqd/0
    5 root       0 -20       0      0      0 S   0.0  0.0   0:00.00 kworker/0:0H
    7 root      20   0       0      0      0 S   0.0  0.0  27:48.14 rcu_sched
    8 root      20   0       0      0      0 S   0.0  0.0   0:00.00 rcu_bh
    9 root      rt   0       0      0      0 S   0.0  0.0   0:00.06 migration/0
   10 root      rt   0       0      0      0 S   0.0  0.0   0:00.17 migration/1


The top command shows what’s going on in your system; head shows the first 17 lines, which amounts to the top 10 processes running.
This shows dump1090-fa using 23.5% of the CPU, and 1.5% of system memory, and that it’s a constant CPU hog. The other components of Flight Aware aren’t in the top 10.

That second incantation I have defined as:


$ alias top10='top -n 1 b | head -n 17'

as I use it often to see what’s going on.

bob k6rtm

Today I got this in the mail.
Plan is to put this on our roof (part with the holes goes underneath the rooftiles), bend the other end so it’s vertical.
Then attach a piece of PVC pipe (I found some laying around which is about 2.5cm in diameter) to that end and mount the antenna to the PVC pipe.
The PVC should be long enough so the bottom part of the antenna is above the roof ridge so about 50-80cm. long.

My plan is to get the FA antenna; the listing says it can be mounted to a mast between 2-5cm so 2.5cm PVC should be OK right?
I’m also wondering if I should get the filter. It’s another €20 and not always needed, sometimes even makes the results worse.
Flightaware says I could be usefull if the antenna location is within 200 feet of a cellphone tower or other strong radio signal; in my case the nearest tower is 3700 feet away.
There is also a amateur mast about 1300 feet away.

EDIT: someone on another forum mentioned in the package there was a note that the filter was essential to work (correctly) with the FA Pro Stick?

My plan is to get the FA antenna; the listing says it can be mounted to a mast between 2-5cm so 2.5cm PVC should be OK right? Yes
I’m also wondering if I should get the filter. It’s another €20 and not always needed, sometimes even makes the results worse. Not in my experience
Flightaware says I could be usefull if the antenna location is within 200 feet of a cellphone tower or other strong radio signal; in my case the nearest tower is 3700 feet away.
There is also a amateur mast about 1300 feet away. It is still useful to act as a bandpass filter for the dongle, which is susceptible to strong signals between 25MHz and up to 2.4GHz.

EDIT: someone on another forum mentioned in the package there was a note that the filter was essential to work (correctly) with the FA Pro Stick? The FA Pro has a preamplifier built in, so the filter is necessary for the above reason, which will be exacerbated by the preamplifier. Bandpass filter is always a good idea with these dongles if you are looking to monitor a specific frequency

For my setup a filter is essential. 2 aircraft without it, 200 with it
That is either the FA filter or a better cavity filter. There are so many cell towers and radars in NYC that I use a cavity filter for better results. You can use just the FA filtered, as many others in NYC have done.

Thanks. I think I was settled on the filter already since going through all the trouble of going up the roof etc. I might as well do it right. :unamused:

Just ordered the FA antenna and filter on Amazon.de. I guess I’ll have to wait some time for the FA stick.
Tomorrow I’m going to look for a source to get the KOKA 9 TS coaxial cable.
Then I’ll guess I’m going to have to climb the roof around Saterday :unamused:

Why don’t you reconsider the cable. KOKA 9 TS is with 75 Ohms impedance.
It will be better to get a cable with 50 Ohm impedance for maximum compatibility.

My understanding from this forum is that it will be fine.

Attenuation of Koka 9TS is 860 MHz 17.2 dB / 250m and 1750 MHz 25.1 dB / 250m.

Actually; the main thing I’m worried about is the 52cm. flat RG6. It is necessary as I have said before (can’t drill holes in window frames or exterior walls) but that’s the main bit that concerns me.

But I will test this out but temporarily removing this piece and see what results are. (Weather is great this week and apparantly next week too so having the window slightly open isn’t that big of a problem)

The FA antenna should come in tomorrow, RG6 is apparantly fine so I’l order some 15 meters of that. I’m really curious what the results will be.

EDIT: ordered 15 meters of KOKA 9 TS and 2 F-connectors. Should be delivered tomorrow or Saturday.

I received the KOKA cable and FA antenne + filter.
Just for fun I mounted the antenna on the same place and connected it via a (Ebay) MCX-F pigtail to the Ebay dongle.
Not good. I have terrible reception and apparently I’m not feeding either. (sometimes)