I would like to build a small circuit to measure with my oscilloscope the power emitted by the 5.8GHz video transmitters mounted on my drones and searching I found this answer:

https://electronics.stackexchange.com/a/74370/228767

The question recommends using a 50 ohm dummy resistive load.

Why was that value chosen? is it random or can the optimal value be calculated?

Personally I will have to measure signals with power lower than one watt.

Also, to have precise measurements and avoid damaging the video transmitter, is that 50 ohm resistor sufficient, or is a more complex circuit necessary as shown here?

https://www.ab4oj.com/test/pwrmeas.html

I would like to build a small circuit to measure with my oscilloscope the power emitted by the 5.8GHz video transmitters mounted on my drones. On searching, I found this answer.

The question recommends using a 50 ohm dummy resistive load.

Why was that value chosen? Is it random or can the optimal value be calculated?

Personally I will have to measure signals with power lower than one watt.

To have precise measurements and avoid damaging the video transmitter, is that 50 ohm resistor sufficient, or is a more complex circuit necessary as shown here?