Polarity for 2x2 and for 3x3 Mikrotik devices

RouterOS Wireless Networking
1

A couple of polarity questions:

On a 2x2 Mikroitk device , to ensure compatibility with all 2x2 Mikrotik devices with internal built-in antennas connecting to a Mikrotik 2x2 device which uses external antennas — What is the first antenna polarity supposed to be (Horz or Vert). I assume the second antenna would be the other polarity.

Now for my next question,
On a 3x3 Mikrotik device, am I correct in guessing the first 2 antenna polarities are the same as a 2x2?
What polarity is the 3rd antenna? Is it something like a 45 degree (split the difference between Horz and Vert polarity???

It makes sense that when using Mikrotik client and AP devices with internal built-in antennas (such as the SXT) that it just works. However, If I want to replace one or several SXT (2x2 or 3x3) with other Mikrotik devices using external higher-gain antennas, what polarities should I be using for antenna 1 -and- antenna 2 -and- antenna 3?

And now for another question - Can a 2x2 or 3x3 use all Vertical omni antennas with physical seporation on a tower so that I can get a 360 degree coverage? (providing the client 2x2 or 3x3 antennas all match the same polarity as the AP.

OK - another question… When using external antennas in a 2x2 or 3x3 system (not built in dish antennas with 2 or 3 coax connectors), what is the best physical seporation? Example - if using 3 antennas in a 3x3 system on a tower, should it be antenna 1 on top - then below antenna 2 - then below antenna 3 — or instead of top-heading-down-the-tower 1,2,3 or something like 1,3,2 ?

Thanks for input
North Idaho Tom Jones

2

The first CH0 is horizontal, the second CH1 is vertical [CH0<=>CH0, CH1<=>CH1]
OR
The first is -45° [315°] (H -90° [270°] counterclockwise of 45°), the second is +45° (V 0° counterclockwise of 45°) [CH0<=>CH1, CH0<=>CH1]

when is present the third CH2 or is +45° on the master and -45° on the slave (or vice-versa) and the other are CH0=H and CH1=V [CH0<=>CH0, CH1<=>CH1, CH3<=>CH3]
OR
CH0: -60°; CH1: 0°=V ; CH2: +60° and on the other side the vice-versa is not needed [CH0<=>CH2, CH1<=>CH1, CH3<=>CH0]

all depend on what antenna models you use.


THE ANTENNA MUST BE ONE ALL-IN-ONE OR USE FOR EACH CHANNEL ANTENNA OF SAME MODEL, AND MUST BE ALL ON THE SAME PLACE.
You can not put CH0 on top of building and use CH1 as office AP.
For do that you need to use multiple radios.
Also you can not mix antennas with different gain and/or different cale length.

3

Thanks for the quick prompt reply.

So - Now I need to check and see …

  • if all Mikrotik devices for 2x2 (such as the SXT) 2x2 are CH0–>Horizonal and CH1–>Vertical
  • if all Mikrotik devices for 3x3 (such as the SXT) 3x3 are CH0–>Horizonal and CH1–>Vertical -and- CH2–> +45

whew… I almost need to make a drawing and put a picture on my wall…

It is pretty clear that you have to be careful on polarity when using external dish antennas on long-distance shots for 2x2 and 3x3.

I can not even think of what is going on with 4x4 through 8x8 or 16x16

Tom Jones

4

MikroTik do not produce any antenna or integrated device 3x3 for now, you must see the characteristic of antenna you put on devices.

My network at begin are only “V”, all the AP and all the CPE.

When SXT and Sextant come out I must activate ch1 on both rx and tx or the device “ear” only orizontal on CH0…

Now, time to time, I have upgrade near all principal AP to dual pol. H/V, and now the sextant and sxt I place before connect also on is own channel 0

SXT are fixed CH0 = H and CH1 = V, but you can open QRT and Sextant and invert CH0 and CH1 if you forceful need CH0=V and CH1=H

5

re: …MikroTik do not produce any antenna or integrated device 3x3 for now…

My bad …
I thought I spotted a Mikrotik SXT AC 3x3 somewhere - but I guess I was just looking at the channel width 20-40-80

Hmmm, I wonder how long till Mikrotik comes out with an integrated Point-to-Point AC 3x3 solution and what the max possible throughput could be (in real life for any kind of distance)?