South Africa

[HermanZA]

... I occasionally watch on FR24 the SAA A340 that flies into Perth from Johannesburg most afternoons....

I did not quite catch that one for you yet, but there's one coming your way and that radar station has a very nice reach!
FALE2.JPG

And 23:40 SAST I got your flight! Station FAVG has a reach of about 680km there...
SA280.JPG

[HermanZA]

Mine doesnt have the resistor at the top, and is in a 22mm pastic tube from the plumbing section in the local diy store (sold as overflow pipe) held in by a plug of hot melt glue at the top and bottom. Total cost eas about 3 british pounds. Most awkward item was to get an adapter from tv arial style coax plug to the tiny socket used by the tuner dongle.

Is yours open ended, or closed/shorted at the top?
For the love of a flying machine, I simply could not find a 50/75Ohm resistor in any of the electronic scraps I have. And to order a 5c component, the courier fees would be about 1500x times the value of the component.

[peterhr]

Mine is open ended at the top - which might turn out to be fortunate

looking at http://forum.flightradar24.com/threa...-antenna/page7 user abcd567 has used RCA D903 preamps, these are like $5 each and comprises an amp and a choke to pass on line power to the next device ... I've ordered 2 of those and because the antenna is open ended I don't have to worry about decoupling the power at the antenna side of the amplifier.
The amplifier seems to be in the UK on Amazon http://www.amazon.co.uk/dp/B001U4KTU6/ ... hope it works ...

[HermanZA]

With my little whip antenna I am getting average 250km radius.... tempted to (yet again) dismantle rooftop and connect the DIY collinear. I am getting more exercise radar-spotting, than doing anything else! :-)
PeterHR - if you were any closer, I sure as heck would have invited you for some tea and scones for all the help and advise you are dishing out here!

[peterhr]

Hey, I don't know if my set-up is optimal - I'm surrounded by trees and my mast is not high enough, and I'm surrounded by much faster F- and N- receivers so my contribution doesn't register on FR24. I set-up my registration to FR24 maybe 6 months ago and got T-EGBB19 ... I've seen T-EGBB35 on the map so the number of stations has almost doubled in that time (competition is fierce) and the area where EGBB counts a the nearest airport is small (we are surrounded by EGCC 90Km N, EGNX 45Km NE, EGGW 115Km SE, EGGD 135Km SW, and there're more! - so severe overlap with users with those airports as nearest)

I don't know the velocity ratio of the cable I used for the co-linear and am tempted to try something similar.

[dogzbody]

I'm still a noob-wannabe in Roodepoort, Gauteng. My Raspberry Pi and USB RTL-SDR should be arriving later in the month. I want to make my own antenna, and set up a permanent station, but I thought I'd fool around with what I get, first.

I'm wondering if any fellow South Africans can give me any local tips?

[HermanZA]

Welcome to the forum and to the ADS-B tracking family.

We have some excellent tutorials from forum member PeterHR on setting up your PI, even with precompiled images images available. Forum member ABCD and a few others, has done extensive work and trials on antennas, all all of that should be able to give you a good start in getting it up and running.

Us lot in South Africa have the local forum http://www.africanskies.org/ available where we discuss seen aircraft and unknowns, etc.
If ever you do get stuck or need help, just ask on any of the forums - help will be available.

[Bell 407]

I'm still a noob-wannabe in Roodepoort, Gauteng. My Raspberry Pi and USB RTL-SDR should be arriving later in the month. I want to make my own antenna, and set up a permanent station, but I thought I'd fool around with what I get, first.

I'm wondering if any fellow South Africans can give me any local tips?

Great that you want to construct your own antenna, but if you want a dedicated 1090mhz ADSB unit there is a company in Pinetown who will construct and deliver one to your door. They are called Antronic and their contact number (031) 705-3655.

[HermanZA]

Have to say, I wasn't happy at all with the antenna they constructed for me. Just plain bad coverage for R1200 .... and doing the whole thing of sending it back via courier to test and bringing it back to me, made it not worth while.
Had better results with a simple J-pole I made.

[peterhr]

I'd suggest starting with a simple dipole, like the one at the end of the raspberry pi setup PDF here http://forum.flightradar24.com/threa...e-to-feed-FR24 (downloads at post 8).

That will give you up to 200nm if your down lead isn't too long - grow from there.

[SBSer]

Be aware that the antenna from Antronic is a modified J-pole and therefore not suitable for an amplifier unless decoupled. In other word it tests as DC short.

I would suggest you start off with a simple di-pole as described by abcd and peterhr or a simple quarter wave with ground plane (spider). Use RG6 satellite co-ax cable and pre-amp and get it up as high as possible. You will be surprised. The Qantas track in post #16 above used this exact setup using a quarter wave.

Plenty examples in this forum and advise in this forum under Technical Matters.

[dogzbody]

Thank you, HermanZA and Bell 407! It's good to know that the ADS-B community is so active.

I can't wait to get my hands dirty and start fooling around, even just with the little stock whip antenna at first.

I'm glad I can get an antenna locally - that's bound to work out cheaper than an import. But I know what a lazy bum I am - and once I've bought an antenna and installed it, I'll NEVER experiment with making one!

I think I'm going to try my hand at PeterHR's dipole first, maybe, and compare it to the little magnetic whip (to give myself an ego boost); and then decide what's next from there...

[peterhr]

Thank you, HermanZA and Bell 407! It's good to know that the ADS-B community is so active.

I can't wait to get my hands dirty and start fooling around, even just with the little stock whip antenna at first.

I'm glad I can get an antenna locally - that's bound to work out cheaper than an import. But I know what a lazy bum I am - and once I've bought an antenna and installed it, I'll NEVER experiment with making one!

I think I'm going to try my hand at PeterHR's dipole first, maybe, and compare it to the little magnetic whip (to give myself an ego boost); and then decide what's next from there...

The antenna i use reqularly (see my sig) with an amplifier sees 250nm, an amplified dipole sees 225nm - what is important is to get the antenna above the height of nearby obstructions ... usually your own roof.