Comment by BizarroLand

That's about it. Antennas aren't anything but wire or a small sheet of metal, all you need is something to increase the amount of metal exposed to the signal.

This is a quick & dirty diy "solder on some more metal & an antenna" tutorial:

https://community.home-assistant.io/t/how-to-add-an-external...

Solder mask might have been a better cover than the one shown, but the hot glue would do in a pinch.

Also, as far as resistor goes, there is no spec for the resistor. It's a jumper, that's all.