AirNav Systems Forum
AirNav RadarBox and RadarBox24.com => AirNav RadarBox and RadarBox24.com Discussion => Topic started by: AirNav Support on November 09, 2007, 09:52:01 PM
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Intresting information and pictures showing ADS-B reception from a customer:
Concerning the antenna discussion I have a few screenshots from Denmark and Germany:
and my problem with the Berlin TV Tower.
With the included Radarbox antenna in a height of 3m a.s.l. on the roof of a sailing yacht cabin I have had coverages of up to 180 nm.
(http://www.akzah.com/anrb/prop%20pics/pic1.jpg)
Pic 1: Four hours reception in the port of Gudhjem on Bornholm Island with a 70m hill in southwest direction
(http://www.akzah.com/anrb/prop%20pics/pic2.jpg)
Pic 2: 30 minutes monitoring during the departure from the port of Gudhjem on Bornholm Island
(http://www.akzah.com/anrb/prop%20pics/pic3.jpg)
Pic 3: Position about four hours off Christiansoe in the northeast of Bornholm Island
My home location is only a few kilometres from the TV tower in the centre of Berlin. The antenna I use is a GP1090 by WIMO mounted at the side of an antenna mast and there are 35 metres of Ecoflex10 cable between antenna and receiver. The following pictures show the HF spectrum and signal strengths on the roof of my apartment house:
(http://www.akzah.com/anrb/prop%20pics/pic4.jpg)
Pic 4 shows the spectrum of several VHF radio stations, TV stations and other signals emitting high power and jamming my preamplifier
(http://www.akzah.com/anrb/prop%20pics/pic5.jpg)
Pic 5: The selectivity of the GP1090 antenna suppresses signals outside of the 1090 MHz band
(http://www.akzah.com/anrb/prop%20pics/pic6.jpg)
Pic 6: The AS 1090 preamplifier eliminates even more signals and raises the signal levels in the 1090 MHz band.
(http://www.akzah.com/anrb/prop%20pics/pic7.jpg)
Pic 7: GP1090 - coverage without preamplifier
(http://www.akzah.com/anrb/prop%20pics/pic8.jpg)
Pic 8: GP1090 - coverage with preamplifier and a little shading by the antenna mast in NE
(http://www.akzah.com/anrb/prop%20pics/pic9.jpg)
Pic 9: GP1090 - coverage with preamplifier and shading by the antenna mast in WNW
(http://www.akzah.com/anrb/prop%20pics/pic10.jpg)
Pic 10: This picture shows the shadows of the next mountain ranges: Harz in the southwest, Fichtelberg and Keilberg in the south, the Giant Mountains in the southeast and the antenna mast in WNW
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Hi to all
Thanks for this excellent descriptions. The first capture has a marvelous reception without any external improvement. Only the included RB (amazing) antenna fitted at 3meter high. Has coverage of the maximum range to Mode-S in clear sky. The second capture in semi flat ground area (antenna is 35meter high) has same coverage using external equipment that is costing a few hundred Euros. My opinion for the second case is that two problems exist. First is the length of coaxial cable, connectors, adapters N type to SMA etc and loss of them (4-5db plus or minus) and second is the out of band (1090MHz) strong signals. The external equipments works well and of curse like band pass filter and amplifies the signal, cover the cable etc loss, but still have not very important deferents to coverage of the first capture. Conclusion: Clear sky and clear sky again for the best results.
Chris