Yes, be very careful to stay within lawful ERP. Some devices are illegal to use with external antennas. Of those that can connect an external antenna, the specs of acceptable antennas are provided with the equipment.

If you are in the USA, and you have the appropriate Amateur License (Tech class or higher), and you choose channels that are in the Ham Bands, Then it's perfectly fine to use these as ham radio links. https://www.arednmesh.org/