Weak signal and Low power activities

Some hams use VHF or UHF frequencies to bounce their signals off the moon. The return signal is heard by many other hams who also do EME (earth-moon-earth). The antenna arrays are massive so a lot of real estate is needed. Other hams transmit with very low power. Signals on the order of 5 watts or less are heard all over the world by these QRP (low power) operators.