What if I can’t remove my mains lead?
Cut off the mains cable about 3 inches (7.5cm) from where it enters your equipment and wire on a male IEC plug as shown.
What about the remaining few inches of old flex?
It'll form a full wavelength aerial at c. 3.9 GHz ...
In the meantime the old mains lead with a 13A plug at one end and bare wire at the other will make a nice toy for a child to play with.