PilotAware
British Forum => General Discussion => Topic started by: ChrisBell on October 20, 2015, 09:45:54 pm
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Okay got a result on mine today
But not picking up all or even most of the adsb traffic reported in the area by flight radar.
So I'm thinking maybe it's the antenna supplied ?
Does that sound reasonable? If so I'd like to mount a replacement to the pi case
Any ideas ?
Chris
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Chris,
Is your antenna in side the house? If so try it outside first just to confirm you have poor reception. It does make a big difference out side. Also it does better line of sight.
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Couple of things here.
1. Yes, the antenna needs, ideally, to be outside, especially if yours is a modern house with aluminium clad foam insulation between the walls - the best possible RF shield! I have mine by a south facing window and I see far more stuff to the south than I do elsewhere.
2. The supplied antenna is actually too long for ADS-B on 1090MHz, It is resonant at about 800MHz and like any antenna its performance will deteriorate markedly either side of resonance. I cut mine down to be more or less the correct length for resonance on 1090MHz. It made quite a big difference! Whip length is 7cm. You'll get a further improvement by mounting it on a ground plane, e.g. a metal tin lid.
Unfortunately there are no "magic bullets" with antennas: they need to be resonant and they need to be in the clear to work properly.
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Ground Plane.....
Ground plane is very very important and is often overlooked.
A metal plate the diameter of a CD is a good starting point.
Steve
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I have built one using a sma fittings and fly lead from the ARF kit.
Tested on my sbs base station in the open at roof level I can see traffic as far away as Bristol.
Will attach a pi if I can. Not up to speed on the computer, thanks
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Screen from sbs base station with home made areial.
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Okay got a result on mine today
But not picking up all or even most of the adsb traffic reported in the area by flight radar.
So I'm thinking maybe it's the antenna supplied ?
Does that sound reasonable? If so I'd like to mount a replacement to the pi case
Any ideas ?
Chris
Well firstly you need to check what your navigation settings are in set up menu regarding reporting of "other traffic" most stuff outputting ADS-B will be commercial so check that your setting is to around 40 000ft and then if you still not getting much traffic then look at your antenna location and so on. If you surrounded by tree's n buildings, unless you have direct line of sight you wont get much.
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Re flight radar. Not all commercial traffic transmits ADSB. My sbs base station does not show all the aircraft that flight radar does. FlybeQ 400 do not show on adbs.
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Re Flybe BEE4PE not visible on Adsb
EZY29EA and AFR72 are on sbs and radar 24.
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And sbs base station.
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You can make a better antenna than a whip with ground plane. What's quite popular in ADS-B reception is a collinear made with coax. It's quite easy to make.
http://www.balarad.net/ (http://www.balarad.net/)
https://www.youtube.com/watch?v=TkUYdCPFXXs (https://www.youtube.com/watch?v=TkUYdCPFXXs)
The other thing is that FlightRadar24 also has multi-lateration, so it'll use several stations to triangulate a mode S contact which doesn't have ADS-B. It won't show up on our setup.
Getting out in the open helps a lot though. The other day when driving from Popham to Andover with the little antenna (not cut to size) on the dashboard (not even on the roof), I was picking up aircraft from north of Birmingham down to France, from Wales to Kent.