In linux there is a command called iwconfig which shows Tx-Power in its output. How to measure antenna power in MacOS? The airport utility in mac just shows the datarate and not the power in db.

I want to see the current Tx-power value. I do not want to change it or mess with it. I know that it changes dynamically according to the Region or other factors, but how to monitor the current value?

  • See this answer. It includes the information you're looking for. – Allan Oct 1 '18 at 13:17
  • I don't think it has @Allan. I already checked. I even captured packets with wireshark and checked their radio fields, still no sign of Tx-power. – shidsun Oct 5 '18 at 13:24

The Tx- Power is coded in to Firmware and has a maximum allowed by law. (FCC in the US)

Apple did offer the possibility to change the Tx-Power in its older version of Airport utility Ver 5.6

Tx Power

You can download it and try.

The 802.11n (5th Generation) - Airport Extreme card is set to

20 dBm (nominal) Output Power.

The iwconfig does not actually report the output power of the antenna. That is not possible. An antenna can not measure its own output, but a secondary antenna can. The iwconfig power output is a misnomer, it reports the power going in to the circuit that powers the antenna.

  • is there any convenient command to see the current value? In that case I should check the frequency each time and refer to table, and still I am not sure how region affects it. I just want to see it. In linux it is part of output of iwconfig. – shidsun Oct 1 '18 at 12:39
  • Also the link you sent is for linux OS not mac. – shidsun Oct 1 '18 at 12:39
  • Whoa... "messing with it" is not against the law. Exceeding the power limit is. I routinely lower the transmit power on APs to better "shape" the signal; I would rather have 3 AP's a 40% power than 1 AP at 100% – Allan Oct 1 '18 at 13:13
  • @Allan so do you know the answer to this question ? It is against FCC regulations exceeding they set limits. – Ruskes Oct 1 '18 at 16:30
  • It's not illegal to change the tranmission power of your WiFi device. It is illegal to exceed the power limits (1W). 200mW is enough for most situations so bumping up to 300mW is probably overkill, but not illegal. I actually do "in room" WAPs (300 ft^2 or 28 m^2) coverage and turn the power down to about 15mW. – Allan Oct 1 '18 at 17:08

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