Hi all,
I need help with interference problems.
I have 2 routerboards in a telecomunications tower. http://www.torredecollserola.com/
The hardware there is 2x X86 with 1 XR5 and 90º sector antenna with 16dBi and 60 cms antenna wire, working at 5.4 GHz. Mode ap-bridge. TX power to 17. HW retries: 15. ROS v2.9.51.
The tower is full of other 5.4 GHz equipement, radio, TV, etc..
We also have 15 costumers connecting to the RB600’s from 2-3 KM distance. Hardware: RB411 with XR5 and 19dBi directional antenna. Mode station. TX power 17. HW. retries 15. ROS v3.10
My problem is that this point to multipoint WLAN is to make VoIP calls from costumers to costumers. As my CCQ isn’s 100% I have a very low paquets lost, but sometimes my links lost 1 or 2 pakets.. and this could make my calls dead or very bad sound.
My CCQ in station side is 90/50 more or less. And signal is about 60. I think this problem is because in the tower we have a lot of equipement making interferences. We tryed all the channels and tried to change TX power on both sides. If I put more TX power we have less CCQ.
How can I reach almost 90/75 CCQ to improve my VoIP calls?
Anyone can help me to avoid or minimize this interferences?
I send you a pic with the antennas situation.
Here is where are my costumers. (all with direct view..)
Thanks,
Martín.
Hello,
the cases on the second picture seem to be made of some kind of plastic. If that’s true, I would recommend using metal cases well grounded. But with all the other stuff around with probably much higher signal power, I don’t know if a Bandpass filter or some further shielding of cables (and perhaps on Backs of antenna) would help to solve your troubles.
By the way, what are those nice shiny cases on the upper picture? (silver with yellow ends). Seen some of those somewhere before, but couldn’t get information who makes or sells them.
Thanks,
Schnulch
Hi,
cases are from Lobometrics APs (Lobometrics are x86 and routerboards with ROS installed..). http://www.lobometrics.com. I couldn’t get info about who sells this cases. There isn’t info on it.
We use always metal cases.
First of all we use all the XR5 at max TX power (27-28) and CCQ have lower values.. Then we put less TX power and we achieve more CCQ.
Where I can buy this bandpass filters and how can I shield the cables? What’s the theorical work of bandpass filters? This solutions could make better CCQ params?
Thanks,
Martín.
Antenna cables could work like small antenna and “catch” signal from other RF- Equipment on your towers disturbing the signal you want to receive. They could be shielded by a “metal hose”, fabric of thin metal wires or similar, connected to case and antenna. Then the unwanted signal would be caught by the outer shield and let to grounding, without getting inside the cable.
Perhaps put a piece of sheet metal on the back of the antenna too, to shield it from signal from the tower?!
Bandpass filters are special elements you can by for the frequency you want to operate your wireless link on, for example 5700 MHz. This filter will only let signal with frequency of ~ 5690MHz to ~ 5710 MHz pass trough, all other frequencies will be reduced by several db or more. This way your wanted signal can pass trough, noise and disturbance from other equipment on tower will be blocked / reduced.
Both actions will only help if the other equipment on your tower causes the problems you have.
Have you tried Nstreme with polling and csma disabled? Perhaps worth a try…
I have used bandpass filters once “in the good old times” when 802.11b was bleeding edge of technology and it helped a lot
in a very dense populated area. But now I use 5 GHz Links, and never needed any filter or similar since. I donÄ’t know where you could by those filters, but google will help you for sure
Have you tried 10 MHz or 5 MHz channel width? Perhaps that could help you too.
Sincerly
Schnulch
Perhaps
Thanks,
we’ll try to make this changes. At the moment we won’t buy this filters because we use diferent channels every week because of interferences.
Martín.