RB2009 Antenna Vs SBS-1e Antenna

[Bigyun2000]

Hi all.  I was wondering if in the future AirNav would supply a better antenna with their equipment.  I have both a brand new ANRB2009 Box and the Alternative SBS-1e.

I wanted to test the antenna's and the results are shown here over a 12hr period.  6 hrs on each antenna connected to my AirNavRB2009.  I was quite surprised at the conclusion.

Conclusion is that a better antenna should be included.  Wondered if anyone else may have done further testing and have different views.

The earlier picture is using the SBS-1e antenna.  The later picture is using RB2009 original antenna.

Thanks

[AirNav Development]

Hi. Have you tried to change antenna positions? The extensive results we have made indicate no difference in range comparing both systems. Anyway you could get a much better result with one system compared to the other if we moved one antenna as little as 20 or 30 cm.

[tarbat]

Well, given that the SBS-1e antenna screenshot was taken at 3:45pm, and the Radarbox one was taken at 10:30pm, I'm not suprised by these results.  There's a lot more aircraft around in the middle of the day compared with the night!!

Suggest you compare like with like. A comparison over a 120hr period would be more representative.

[Bigyun2000]

@Tarbat.

Yes i guessed it was a possibility.  I actually drew around the base of the antenna located on top of my stack system on the ground floor.  Done this so i could place the other antenna in the exact same place.

Will try again over a longer period.
Thanks

[AirNav Development]

We have personally made hundreds, if not thousands, of comparison tests and it is unbelievable how ADS-B is so sensitive to minor changes of the antenna location. If for example you have 2 exactly identical RadarBox units with the same antennas positioned 20 cm from each other on a window you can get 100% more messages on one against the other.

So we did a lab analysis of both system and in terms of sensitivity they are identical ( actually RadarBox gave better results in terms of hardware ) but it is a common opinion, after being used by so many customers, that they are similar in terms of hardware.

[phillou91]

I HAVE TESTED THE TWO RECEIVERS SBS-1 AND RB2009 COUPLED ON  THE SAME ANTENNA (GP1090 antenna ) THE RESULT IS  : RB TRACKS 8 to 10 % MORE AIRCRAFTS THAN THE SBS-1 ! 

[Fenris]

I HAVE TESTED THE TWO RECEIVERS SBS-1 AND RB2009 COUPLED ON  THE SAME ANTENNA (GP1090 antenna ) THE RESULT IS  : RB TRACKS 8 to 10 % MORE AIRCRAFTS THAN THE SBS-1 ! 

Coupled how exactly?

[phillou91]

coupled with a T coaxial connector
Philippe

[Blackthorn]

coupled with a T coaxial connector
Philippe

That would split the impedence of the antenna and effect reception.

[Fenris]

coupled with a T coaxial connector
Philippe

OK, that means that because there is no isolation between the two receive ports, the signal will not split equally unless the two receiver inputs and the cable feeding them have identical length and impedance.

To do this reliably you need a transformer-based splitter which provides 20dB or more isolation between the split signal ports.

[CZUL]

Has anyone tried using a Stridsberg active multicoupler? Is there any risk to the RB by adding a preamp?

[jannuh]

On the "other"forum there are a few using the antenna coupler of RF Systems,
I know for sure Anmar does.

You could asl there...