Antenna on roof, what cable to use?

[Iemand91]

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.

@abcd567

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.

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.

[abcd567]

@Iemand91

…
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.

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 .

[zeek70706]

@Iemand91

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.

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.

[zeek70706]

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

[k6rtm]

@zeek70706

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

[Iemand91]

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?

[k5ted]

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

[jonhawkes2030]

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.

[Iemand91]

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.

[Iemand91]

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 …

[rosen85]

@Iemand91

…Tomorrow I’m going to look for a source to get the KOKA 9 TS coaxial cable.

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.

[Iemand91]

@rosen85

@Iemand91

…Tomorrow I’m going to look for a source to get the KOKA 9 TS coaxial cable.

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.

[Iemand91]

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.

[Iemand91]

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)

[abcd567]

FA antenna requires N-male connector.

[Iemand91]

@abcd567

FA antenna requires N-male connector.

I know, but I forgot to mention that I had the F-N adapter too.

Setup is Antenna - N-F-adapter - F-MCX pigtail - Dongle - RPi3.

[Iemand91]

I think I found the culprit. The problem lies with this F-N adapter. The F connector does not properly connect with other F connectors. It doesn’t fit with my MCX-F pigtail and it doesn’t connect properly with the coax F connectors. The screw thread is a tiny bit different I guess. The Ebay seller sells both Metric and British version of the adapter and I ordered the Metric version (obviously).
But when I look at the pictures of the British version; the F connector looks slightly different. But it just a tiny, TINY difference.

Guess I’ll have to order another F-N adapter, this time the British version. Really bumped about this as I was really curious about the FA antenna and was planning to get everything installed on the roof this weekend…

Now I’ll have to wait a week or two before the adapter arrives from China. Could order it locally but this sort of adapters are way overpriced here.

[k5ted]

@Iemand91

I think I found the culprit. The problem lies with this F-N adapter. The F connector does not properly connect with other F connectors. It doesn’t fit with my MCX-F pigtail and it doesn’t connect properly with the coax F connectors. The screw thread is a tiny bit different I guess. The Ebay seller sells both Metric and British version of the adapter and I ordered the Metric version (obviously).
But when I look at the pictures of the British version; the F connector looks slightly different. But it just a tiny, TINY difference.

Guess I’ll have to order another F-N adapter, this time the British version. Really bumped about this as I was really curious about the FA antenna and was planning to get everything installed on the roof this weekend…

Now I’ll have to wait a week or two before the adapter arrives from China. Could order it locally but this sort of adapters are way overpriced here.

Curious, what is the difference in price between the China one and a locally purchased one?

[Iemand91]

[quote=“k5ted”]

@Iemand91

I think I found the culprit. The problem lies with this F-N adapter[/quote]

. The F connector does not properly connect with other F connectors. It doesn’t fit with my MCX-F pigtail and it doesn’t connect properly with the coax F connectors. The screw thread is a tiny bit different I guess. The Ebay seller sells both Metric and British version of the adapter and I ordered the Metric version (obviously).
But when I look at the pictures of the British version; the F connector looks slightly different. But it just a tiny, TINY difference.

Guess I’ll have to order another F-N adapter, this time the British version. Really bumped about this as I was really curious about the FA antenna and was planning to get everything installed on the roof this weekend…

Now I’ll have to wait a week or two before the adapter arrives from China. Could order it locally but this sort of adapters are way overpriced here.

Curious, what is the difference in price between the China one and a locally purchased one?

The China one is $2.37 / €2.11; shipping included all the way to The Netherlands.
Locally they’re very hard to find but they start online at about €5 all the way up to €12 (and probably more) and that’s without shipping; another €5.75.

[abcd567]

I faced same problem of N to F adaptor. The first one (unbranded) I purchased from a local store, and another one purchased on ebay from china. I then purchased this one (Wilson Electronics) from Amazon.ca, and this one solved the problem. It is double the price of chinese one, but works ok.

amazon.ca/gp/aw/d/B002Z8ZKKA

Please also see these posts, AND a large number of posts in between these two posts.

post187876.html#p187876

post188121.html#p188121

.