Clarification Power Regulations and Chains (11n)

RouterOS Wireless Networking
1

As I understand Power Regulations in different countries limit the Power
sent from one place not from one Antenna.
So sending with two antennas in different directions each of them
has to be limited to send only with xy W Eirp.

In case 2 Antennas send in the same direction from the same place
their tx power has to be summed up. So each of them can only send
with half of max allowed power. (Same applies to overlapping sectors).

So doing 11n with 2 chains in the same direction (one dual pol antenna
or 2 antennas with different pol) each of the chains is only allowed
to send with half the power.

MT does this calculation automatically when I select country and
enter Antenna Gain.

So finally my questions:
When signal is weak it would help to reduce to one chain as send power
increases by 3db for this chain? Or is it better to leave both channels as
the combined power is equally?

So is it better to give customers who have bad signal conditions an antenna
with one chain and more gain instead of a dualpol antenna (which has less gain with
same size).

2

6 in one hand, half dozen in the other.

You gain 3dBi on tx and rx with the dual chain as the antennas are in phase with each other (unless I’m completely mistaken).

To keep it legal, drop 3dB on your tx power. if you are using dual chain, you should still have the 3dB gain on the rx side.

The only way I see this as a problem is if someone ignorant with authority decides that two 30dBi grids + 23dBm in phase equals 106dBi.

At the end of the day, the only way to be certain is to try it out, but I’m betting the 3dB gain of the secondary antenna being in phase will outweigh the extra gain of a different antenna.