Problem with radarbox comstation

[adelgallego]

I have a problem with my radarbox comstation, somehow my antenna is not working properly, this antenna comes with 4 dipsticks, the problem is when y put those sticks the signal decrease significantly and it's not transmitting ATC radio to Radarbox24 servers, why is that?

[Runway 31]

It is not transmitting radio as it has not been set up yet and the 4 rods are the VHF antennas.  If you take them off you will not get VHF.  You will be contacted by email

[adelgallego]

Ok i have some pictures where i can show you my problem

With rods:



the signals is intermittent i'm getting like 2 msg/s and then 0 and so on

Without rods:



Polar diagram


It seems to be a better coverage without VHF antenna rods so i dont know if the VHF antenna is interfering with the ADS-B antenna

Antenna surroundings:

http://imgur.com/a/IJF7K

Greetings.

[Runway 31]

I see that you are situated in between two satellite dishes, I wonder if they are causing any issue.

Were the screen shot taken at similar conditions i.e was only one aircraft present within your reception area when you took it or were the conditions the same for each shot with AVA8532 was on the ground at SKBQ on each one but I would assume that there was a gap between taking the shots as you would need to go onto the roof to do the adjustments with the antenna and then go back to the computer to take the screen grab.  I ask this as the other 3 aircraft may have left your coverage or came into your coverage in the intervening period

 The Polar diagram takes a couple of weeks to even out to give a good representation of your coverage and lessen the spiking

Alan

[adelgallego]

Look at the las screenshot i posted without the rods, i wasn't getting such good reception with the rods on, as soon as i removed the rods this appeared in my screen and the msg/s increased significantly.

Ps: I was wondering if those satellite antennas are the problem but i removed the antenna and moved like 3 meters away i was getting the same reception.

I used TeamViewer app on my iPhone so i could see the PC screen while i was adjusting the antenna.

Andres.

[neroon79]

I did some investigation about antenna types and as far as I could figure out these "dipstick" extentions are used to generate a virtual groundplane. If the 1090MHz Antenna is placed in the white plastic tube and the dipstics are indeed used to generate a virtual groundplane for the VHF antenna, it would be absolutely logical, that the ADS-B brokes down as soon as the sticks are mounted to the antenne. For the ADS-B part of antenna it is like beeing covered by a several square metres big copperplate on top.
From my point of view the extensions should be installedat the lower end of the plastic tube to generate a groundplane for both frequencies.

About SAT the dishes. They shouldn't be a problem. Due to reflection on dishes parabolic reflector you may get range boosts in some directions.

Ingo

[adelgallego]

So the problem is related on the way this antenna was build?

[neroon79]

With regards to your pictures and the few things that  I remember about antenna design the "dipsticks" seeming to be at the wrong position.

But it's difficult to tell from pictures.

Ingo

[adelgallego]

Ok i got an email from airnav service and they told me they will send a RF Filter, let's see if that will fix my problem, until then they should change the way the antenna is built :)