The Story of 146.520 MHz: America's National Calling Frequency for the 2-Meter Band

By Josh Dale & ChatGPT 5/18/2025

Introduction

In the vast world of amateur radio, few frequencies are as iconic—or as debated—as 146.520 MHz. Known simply as “five-two,” this frequency occupies a unique role as the national calling frequency for FM simplex communication on the 2-meter band in the United States. But how did this particular slice of the spectrum become the designated rally point for radio operators across the country? What are the conventions, controversies, and cultural dynamics surrounding it?

This article unpacks the history, policies, and social norms that define 146.520 MHz—and explores its evolving role in amateur radio.


What Is a National Calling Frequency?

A calling frequency is a designated channel where stations can establish initial contact before moving to another frequency for further communication. This promotes efficient use of shared spectrum and ensures that hams can find each other, especially during emergencies or when traveling.

On the 2-meter band (144–148 MHz), 146.520 MHz serves as the national FM simplex calling frequency in the U.S. It’s where many hams monitor and transmit when mobile, portable, or operating outside of a repeater’s range.


Why 146.520 MHz?

The origins of 146.520 MHz as the national calling frequency stretch back to at least the early 1970s. The ARRL’s Repeater Directory (then published by EIMAC) included early references to “five-two” as the designated meeting place for simplex operators. According to archived copies of the ARRL's VHF/UHF Band Plan and FCC filings, the frequency was chosen because:

In 1980, the ARRL Board of Directors passed a formal resolution establishing 146.520 MHz as the national simplex calling frequency for FM voice on 2 meters. This decision, reflected in successive band plans, was never encoded into FCC regulation—but became a de facto standard across the nation.


Guidelines, Not Laws

The Federal Communications Commission (FCC) does not assign national calling frequencies through regulation. Instead, it leaves band usage to “voluntary good operating practice.” That’s where organizations like the ARRL (American Radio Relay League) and regional frequency coordination councils step in.

ARRL’s band plan is a recommendation, not a rule. But it carries weight. Most repeater councils, amateur radio clubs, and emergency response networks align their operations accordingly. The ARRL has consistently identified 146.520 MHz as receive/transmit simplex calling only, not for extended conversations or “rag-chews.”

Still, since it's not law, enforcement is left to community norms. Operators can legally use 146.520 MHz for any permissible purpose, including long conversations or group nets—though many frown upon monopolizing the frequency.


Emergency and Public Safety Use

During natural disasters and emergencies—wildfires, floods, earthquakes—146.520 MHz often becomes a lifeline. Portable hams in the field or mobile operators on the move can quickly establish contact without needing repeater infrastructure.

Its national scope and simplex nature make it ideal for point-to-point communications when infrastructure is down.

Organizations such as ARES (Amateur Radio Emergency Service), RACES (Radio Amateur Civil Emergency Service), and CERT (Community Emergency Response Teams) train members to monitor and use 146.520 MHz during drills and real-world events.


Cultural Divides and Regional Habits

Ask two hams about proper use of 146.520 MHz and you might get three opinions.

Some believe it should be reserved strictly for brief contacts and emergency monitoring. Others—especially in rural or underutilized regions—see no problem with casual chat or even running informal nets.

Across the U.S., usage varies:

Ultimately, responsible operators are encouraged to listen first, avoid monopolizing the frequency, and move to another frequency if extended conversation is desired.


146.520 MHz and the Modern Ham

In an era of digital modes, Internet-linked repeaters, and mesh networks, you might think that 146.520 MHz would fade in relevance. On the contrary, its utility endures.

Handheld transceivers like the Baofeng UV-5R, Yaesu FT-60, and Icom ID-52 default to 146.520 MHz. It remains the go-to test frequency for new radios, portable antennas, and local activity checks.

Groups like Summits on the Air (SOTA) and Parks on the Air (POTA) encourage activators to call on 146.520 MHz when activating sites, often resulting in surprise contacts and pileups.


Etiquette on “Five-Two”

Here are a few best practices when using 146.520 MHz:


Looking Ahead

While some newer hams aren’t fully aware of its significance, the legacy of 146.520 MHz lives on through everyday use, especially in disaster-prone regions. The frequency's unique role—as both a national calling point and a social connector—cements it as an enduring piece of amateur radio culture.

As ham radio continues to evolve, so will the norms surrounding frequencies like “five-two.” Whether you’re calling CQ from a mountain trail, monitoring during a storm, or just testing your new HT—when you dial in 146.520 MHz, you’re tapping into decades of history and shared practice.


References and Acknowledgments