Reduce wifi signal strength

RouterOS Beginner Basics
1

Hello everyone

I would like to reduce the signal strength of my Mikrotik Router via Winbox to reduce unnecessary radiation.

I have read various forum threads (e.g. http://forum.mikrotik.com/t/how-to-reduce-signal-strength/54491/1) and the documentation (https://help.mikrotik.com/docs/spaces/ROS/pages/8978446/Wireless+Interface#WirelessInterface-Generalinterfaceproperties), but it appears as that both are mostly related to older Winbox settings which I cannot find anywhere. From what I understood it used to be the correct apporach to set frequency-mode to regulatory_domain, distance to indoor and then increase the antenna-gain. Given that regulatory_domain is enabled, RouterOS will then ensure that the max. country levels are respected and the signal strength therefore decreases (apologies in advance if this would be nonsense, the above exceeds my technical understanding).

Questions:

  1. I cannot find either frequency-mode nor distance in the Winbox settings and this leaves me thinking: If I increase the antenna-gain without having set neither the frequency-mode nor the distance, will this not rather increase than decrease the signal strength, as there will be no regulatory safeguard?
  2. If not, how should I proceed in RouterOS 7.16.2 resp. what are the best config settings to safely reduce the signal strength to reduce unnecessary radiation based on the config settings below?

My wifi config is quite basic. The config and the outputs are as follows:

# 2024-12-30 15:41:50 by RouterOS 7.16.2
# software id = KSYB-YVIV
#
# model = C53UiG+5HPaxD2HPaxD

/interface/wifi> configuration print
name="2.4ghz Config" mode=ap ssid="XXX" country=Germany
security.authentication-types=wpa3-psk .encryption=ccmp,gcmp,ccmp-256,gcmp-256 .passphrase="YYY”
.disable-pmkid=yes .wps=disable 
channel.band=2ghz-ax .width=20mhz

/interface/wifi> monitor 1
state: running
channel: 2442/ax
registered-peers: 2
authorized-peers: 2
tx-power: 16
channel-priorities: 0:2412/ax,0:2417/ax,0:2422/ax,0:2427/ax,0:2432/ax,0:2437/ax,0:2442/ax,0:2447/ax,0:2452/ax,0:2457/ax,0:2462/ax,0:2467/ax,0:2472/ax

/interface/wifi> radio/reg-info country="Germany" number=1           
ranges: 2402-2482/20
5170-5250/23/indoor
5250-5330/23/indoor/dfs
5490-5730/30/dfs
5735-5875/14
2

For hap ax3 - your device - you need to look at wifi documentation.

you have already set country to Germany, so regulatory domain wise your already within allowed limits of your country.

To reduce tx-power (“radiation”) even more, you need yo increase antenna-gain value. this reduces actual tx power. you can see/check tx-power in winbox wifi interfaces list (add the appropriate tx-power column).

docs:

"antenna-gain (integer 0..30)

Overrides the default antenna gain. The master interface of each radio sets the antenna gain for every interface which uses the same radio.

This setting cannot override the antenna gain to be lower than the minimum antenna gain of a radio.
No default value."
https://help.mikrotik.com/docs/spaces/ROS/pages/224559120/WiFi#:~:text=antenna-gain%20(integer,radio.%0ANo%20default%20value.

3

Instead of setting antenna gain (which is fixed), set tx-power (which is part of the configuration).
The first option is a hack (in my opinion), while the latter is how you should do it.

The correct documentation reference:
https://help.mikrotik.com/docs/spaces/ROS/pages/224559120/WiFi#WiFi-PropertyReference

4

Thanks a lot for your replies infabo and erlinden, very helpful!

In this case two follow-up questions:

  1. @erlinden: If I can simply reduce the tx-power in the config, why was it in other forum posts suggested to increase the antenna gain instead? Does that hack, as you call it, have any advantage over the simple method you proposed?
  2. @infabo and erlinden: So let’s say I opt for the simple method erlinden suggested and adjust only the current tx-power value. The value before adjustment was 16, meaning I can simply enter a lower number and that was it or is there anything else which would need to be adjusted?
5

  1. Suggestion to increase antenna gain was the best available option before ROS version around 6.44 (or something like that) … until that certain version, setting Tx power in absolute numbers had been both complicated (it had to be a table with different powers for different rates) and had potential to destroy performance of Tx chain (it was possible to set too high power and wifi chipset was forced to try to do it … it could fry Tx power amplifier if high Tx power was used too long due to overheating PA … and/or output signal was noisy due to clipping as PA could not deliver power required for certain rates).
    In more recent ROS versions, Tx power setting only adds third Tx power limitation (first is chipset capability and second is country regulatory limit where antenna gain is used in Tx power formula) … whichever limit is lowest limits Tx power at any given moment. And chipset capabilities can’t be overruled any more.

  2. Yes, setting tx-power is all it needs to be done.

6

Thanks a lot for your clarifications, this is easier than expected in this case (especially pleased that I cannot go over the regulatory settings anymore or break any hardware by adjusting it)!

RouterOS set the tx-power to 16 and I now entered 10 in the blank tx-power field. Seems to be working.