Simplex vs Repeater
  • Simplex (aka “Radio-to-Radio”, “Direct”, “Talkaround”, or “Car-to-Car”)
    • Radios are “off network” and talk directly to each other
    • Shorter/limited distance
    • Best for localized operations, short-range tactical communications, and when out of repeater range
  • Repeater
    • Repeaters receive transmissions from the field and retransmit (repeat) them with greater power and usually from a higher altitude, allowing communications over increased distances
    • Coverage distance greater than Simplex
    • Best for communicating over wide areas
Close-up photograph of the radio display screen on a (Motorola APX model) portable radio. The radio screen shot contains the time, battery strength indicator, zone name, channel name, and three menu items across the bottom. Along the top of the screen is an icon of a small arrow pointing to the right in between two vertical bars indicating the radio is currently selected on a simplex channel. There is a red circle around the arrow icon to highlight it as the key topic from ths slide. The radio display contains the following text: the time of 10:05 in the upper left corner, Zone IO1 in the center with DHSTAC directly underneath representing the Zone and Channel Name. Three menu items across the bottom read Mute, Clck, Zone from left to right.