Simple Wireless Tx Power and Antenna Gain

RouterOS Wireless Networking
1

Hey guys, I have an RB951Ui-2HnD. Its wireless specifications says that for 54Mbit/s speed, the transmission power is 25 dB milliwatt. I checked my current Tx power for that rate and it was 17dbm. Now my first question is:

  1. Can I safely increase my Tx power for 54mbps rate up to 25 dbm without damaging my router?
    (According to this page “https://wiki.mikrotik.com/wiki/Manual:Wireless_FAQ#What_TX-power_values_can_I_use.3F”, changing Tx power will probably damage the card.)

The antenna gain of RB951Ui-2HnD is 2.5 dbi. In wireless tab when I activate advance mode there’s an Antenna Gain field with the value of zero. My other questions are:

  1. Is it safe if I change my Antenna Gain up to 2.5 dbi?
  2. Can you really change Antenna Gain that way? I thought that in order to change an Antenna Gain, you must use different Antenna with different Gain.

Thanks in advance.

2

The antenna gain field is used along with your country so RouterOS won’t violate legal limits.

Blindly increasing TX power rarely helps, since the other device won’t be able to transmit back with the same power.

3

You can try but it usually will not allow you to set the tx power above the rated power for each modulation.

In general, higher power doesn’t work well at higher modulations.

4

Thank you guys for your replies.

You’re right Oldman. I can’t change Tx power for specific modulation in Tx Power tab. However if I choose “all rates fixed” mode, I can change it to whatever power I want. But the truth is, no matter what I choose (even when I decrease the power), I still get the default Tx Power in Current Tx Power tab.
About the gain, I can change it but it doesn’t seem to have any effect on AP range or causing any problem. I still believe the only way to change an Antenna gain is to change the Antenna itself.

I wonder if there’s any practical example on Antenna gain and power.

5

Antenna gain is actually used for decreasing total power output when running frequency-mode=regulatory domain.
Wireless chip will adjust power so tx-power output + antenna gain sum does not go out of regulatory domain limits.