Handheld radios are great devices and perfect for short distance communications. Within the typical 1-2 miles clear and fairly reliable communications can be carried on. Raise the radio/antenna up higher and transmit(Tx) and receive(Rx) distances start to increase. While I am not going to get into tremendous detail what a repeater is here I’ll provide a brief explanation. Basically, a repeater is a radio/antenna mounted high in the air which will receive transmissions and transmit transmissions. Due to the antenna height, two radios that could not normally talk to each other directly can communicate via the repeater.
The video below describes a very simple and inexpensive “simplex repeater” that most anyone can make. In this video, the Argent ADS-SR1 Simplex Repeater is used with a handheld ham radio. They make adapters for the Argent so that even inexpensive FRS/GMRS radios available at Wal-Mart can be used for creating a local area repeater and extend communication ranges.
For SHTF communications having a simplex repeater can increase the range and effectiveness of what would typically be a short range set up.