Metal 2shpn w/ 6dBi omni antenna indoor optimization

RouterOS Wireless Networking
1

Hi guys,

I have several Mikrotik Metal 2shpn with 6dBi omni antenna for indoor use and I want each of them to cover a radio of 300 meters with each of them, what is the optimal configuration? I was reading other posts about similar scenarios but I don’t understand which are the fields I should really change in the configuration to provide the optimal signal
Help please?
Thanks!!

2

300m indoor including obstacles? Well, if all clients will be the same powerfull like metal is, maybe… It depends on the clients more than on some settings you can improve on metal itself. Use common settings with regulatory domain and antenna gain correctly set and you will see.

3

Thanks for your answer!
We have ~300 meters with almost no obstacles and clients are mainly smartphones, what do you think?
About the ‘antenna gain correctly set’, how do I know what is the appropriate value? Any reference/suggestion to start?
Thanks!

4

wlan is not only about coverage, take in count how many smartphones or other clients you will serve


how many traffic the wlan has to transport??

5

The internet bandwidth available is low so if I can connect 20 clients on each antenna (I have 8 ) I will be very happy.

What configuration do you suggest?

6

do a predictive site survey (free software can help), in the predictive site survey try different power levels to get an idea of needed power because maximum power not always is better

if you have the ap available do a ap on stick real site survey (some trial software can help)

with an omni antenna you have to try a location not too high for the accesspoint.

that is to locate clients on area of maximum gain of the omni directional antenna

its important to check form accespoint perspective the signal strength of clients during the survey because maybe they are receiving strong signal from accesspoint but if accesspoint do not receive strong enough signal from clients you will have problems.

will be useful to know which antenna are you using and the patterns of it

7

Thanks for your answer, very useful!
I’m using the antenna that is provided by Mikrotik together with the Metal 2sphn:

I noticed that most of the clients connected to my access points have a ‘Tx/Rx Signal Strength (dBm)’ between-65 and -95 and I understood from the documentation in the forum that this is not OK, how can I solve it?

Thanks!!

8

This antenna has 6dbi according to specs. http://routerboard.com/RBMetal2SHPn So you should use regulatory domain, your country and put 6 into the antenna gain field (in winbox see wlan interface, wireless tab, advanced mode). After that the radio will be transmitting with the correct power. Do it with all of your access points and then start your measurements.

Now to your question. Wifi is not like radio broadcasting system that depends on power of transmitter and selectivity of receiver. Wifi is bidirectional, so it has transmitters and receivers on both sides. If you want to connect the mobiles, take into account their transmitting power compared to the power of metal with such huge antenna. What it means? While you will get full signal on the mobile, you will not be able to connect to the accesspoint just because the accesspoint will not hear the mobile or will not be able to distinguish its signal from the noise.

There are some possibilities how to solve this problem:

  1. use panel/sector antennas instead omnidirectional (in case of big halls or open spaces) smartly placed around and not aimig directly against each other.
  2. use more widespread accesspoints with low gain antennas and very low transmitting power forcing the mobiles to roam instead of holding it connected to accesspoint just because the mobile gets still strong signal from ap regardless the ap barely hears the mobile.

Have you seen this page? https://en.wikipedia.org/wiki/IEEE_802.11#Protocol Everyone should before wanting to get 300m indoor link between ap and mobile phone.

(on the opposite, I managed to have almost 1km link between groove with 7dbi omnidirectional antenna and a mobile phone)

9

Very useful and clear, thanks!!

10

A few other general rules to consider…

Antenna gain is reciprocal meaning you also get the gain advantage on the receiving side if the client is in the antenna’s coverage area. This can help you capture weaker clients. It’s sometimes better to lower the power output and use a higher gain antenna or, as jarda said, lower both to create a smaller cell.

An omni-directional antenna is really only omni-directional perpendicular to it’s axis. Like a wheel on an axle. It gets its gain by making the wheel thinner but wider. Most people disregard this but if your antenna is significantly higher or lower than your clients, you may want to tilt the antenna. There are places I position the antenna horizontally just to tune coverage.

Watch what’s around your antennas. A big grounded metal object near an antenna will usually act as a ground plane and deform the beam pattern towards it like a magnet. Conversely, big metal objects further away will usually reflect. This can hurt or help.

Experiment. Despite what I or anyone else says, every environment is unique. I’m working on a project for large apartment complexes at the moment and despite having 35 years of RF engineering experience I’m only 70% accurate in my predictions of what an environment will require for coverage. I’m usually pretty close on quantity but it’s placement and orientation that’s the issue. :slight_smile: