HAM Radio
Repeater directories and frequency references for amateur radio
Amateur radio gives you access to a wide network of repeaters across the country, many of them in mountainous and remote areas where cell service does not reach. A Technician-class license is all you need for VHF/UHF repeater access on 2m and 70cm. Use these resources to look up repeater coverage along your route before heading out.
- RepeaterBook Web App — Free, open repeater directory for amateur radio. Search by location, frequency, or band to find nearby repeaters along your route. One of the most comprehensive and actively maintained repeater databases available.
- RadioReference Web — Encyclopedic radio frequency database covering amateur repeaters, scanner frequencies, and band plans. Useful for identifying what radio infrastructure exists in the area you are traveling through.
Emergency Best Practices
Monitor 146.520 MHz. This is the national 2-meter FM simplex calling frequency and the de facto backcountry emergency frequency. If you are out of repeater range and need help, call here first. Any amateur operator within simplex range — typically line-of-sight, 5 to 30 miles in mountainous terrain — may hear you.
- Program 146.520 MHz into every radio you carry, ideally as a priority or scan channel
- Before a trip, look up repeaters along your route on RepeaterBook and program the top 3–5 into your radio with correct offset and tone
- Test your radio and antenna before leaving the trailhead — a short transmission on a local repeater confirms your setup works
- Carry a spare battery or battery pack — cold weather and elevation drain batteries faster
- If calling for help on simplex, state your call sign, location (coordinates if you have them), the nature of the emergency, and the number of people involved — repeat at intervals
- Know the difference between simplex and repeater operation — when repeaters are out of range, switch to simplex calling frequencies
- Keep transmissions brief and clear — in an emergency, say “Emergency” or “Mayday” to get priority
National Calling and Emergency Frequencies
These are the standard national simplex calling frequencies. Not repeater frequencies -- they work radio-to-radio, no infrastructure needed.
- 146.520 MHz — 2-meter FM national calling frequency. The most widely monitored simplex frequency in amateur radio and the de facto emergency channel in the backcountry. If you only program one frequency, make it this one.
- 446.000 MHz — 70-centimeter FM national calling frequency. Useful as a secondary option. UHF can sometimes penetrate terrain features that VHF cannot.
- 52.525 MHz — 6-meter FM calling frequency. Relevant only if you carry 6m-capable equipment, which is less common.
State Emergency Repeater Networks
Several states maintain linked repeater networks specifically designed for emergency communications. These systems connect repeaters across wide geographic areas so that a single transmission can reach operators across an entire region. If you are traveling through one of these states, programming the local input frequency for the nearest repeater in the network gives you a backup communication path.
- CERN — Colorado Emergency Repeater Network (Colorado) — A statewide linked VHF repeater system across Colorado, including coverage in many mountain areas. Designed specifically for emergency communications.
- SARNET — Statewide Amateur Radio Network (Florida) — A statewide linked UHF repeater network built for emergency and public service communications. Closely integrated with Florida's emergency management infrastructure.
- WIN System — Wide-area Information Network (Southern California) — A large linked repeater network covering Southern California. Heavily used for emergency communications and ARES/RACES activations.
- ARCA — Arizona Repeater Coordinated Association (Arizona) — Coordinates repeater infrastructure across Arizona with emergency net capabilities.
- CACTUS Intertie (Central Arizona) — A linked repeater system in central Arizona connecting multiple repeaters for wide-area coverage.
- Georgia ARES Linked Repeater System (Georgia) — Statewide linked repeater network run by Georgia ARES for emergency communication across multiple counties.
- WA-ARES Linked Repeater System (Washington) — Washington State ARES maintains linked repeater infrastructure, particularly concentrated in the western part of the state.
Most states have ARES (Amateur Radio Emergency Service) and RACES networks too -- volunteer groups that activate during disasters. Check your state's ARRL section for ARES nets and frequencies near wherever you're headed.
- ARRL Section Information — Find your state's ARRL section and its ARES/RACES contact information.