Ground wave propagation employ vertically polarized waves around & less than 2MHz.

Advantages:

1] It is less affected by interference.

2] It gets less absorbed and therefore can travel large distance.

3] It is vertically polarized.

Disadvantages:

1] Due to variations in earth's at-mos. density, polarization can be affected.

2] If polarization changes to horizontal, or has norz component, it gets s/c.

3] As a reason, distance cannot be too large.