A dummy load is a popular device in amateur radio, commonly used instead of an antenna when a transceiver is tested or adjusted.
Practically it is a device that simulate an antenna, and permit to test transmission without radiating, absorbing the amount of power that the transceiver delivers.
In these examples you will learn how to homemade your own dummy load.
High Voltage Dummy Load 3000 OHMS, 5400 WATTS There are 45 layers of 6 resistors, each one being 400 OHMS @ 20 Watts for a total of 270 resistors
In this article the schematic is of AA5TB QRP power meter and dummy (50 Ohm) load combination
This project will demonstrate how to build a dummy load, and measure power correctly
If your doing any home brewing gear for ham radio its a great idea to have a dummy load. This will to your radio be the perfect antenna...it will never radiate but your radio sees a perfect 50 Ohm impedance.
https://youtu.be/Gn0HaZMYzro