Radio Field Guides

One GMRS license covers your entire immediate family. The ham Technician exam is a 35-question multiple-choice test from a public question pool — most people pass after a weekend with a free study app (HamStudy.org). Anyone may listen to anything without a license — licenses are for transmitting.

On marine VHF 16, aviation 121.5, or any channel where someone might hear you:

1. MAYDAY, MAYDAY, MAYDAY
2. This is [boat name / callsign / who you are] — say it three times
3. MAYDAY [name] — POSITION [lat/long, GPS, or landmark bearing/distance]
4. Nature of distress (sinking, fire, medical…)
5. Assistance required · Number of people · vessel description
6. OVER — then release the mic and listen

No answer? Repeat. Keep intervals to listen. If not life-threatening, use PAN-PAN instead. In a genuine emergency FCC rules let any station use any frequency and any power necessary (47 CFR §97.405).

A simple rendezvous convention when the grid or phones are down: every 3 hours (from midnight local), turn on your radio on channel 3, and monitor for 3 minutes. CB ch 3 (26.985), FRS/GMRS ch 3 (462.6125), or MURS ch 3 (151.940). It conserves battery while guaranteeing separated groups a scheduled meeting time on the air. Agree on your family's variation ahead of time — the plan you rehearsed is the one that works.

Hams in the backcountry (and everyone in a disaster) monitor the national simplex calling frequencies for 5 minutes at the top of every hour, minimum 7 AM–7 PM local: 146.52 (primary) · 52.525 · 223.5 · 446.0 · 1294.5 MHz. If you need help, call at the top of the hour. Priority transmissions start with the DTMF tone or the words 'Priority, priority.'

A repeater listens on one frequency and re-transmits on another from a high site, stretching your handheld's 2 miles into 50. To use one you program: the output (what you listen to), the offset (2m: ±600 kHz, 70cm: ±5 MHz), and usually a CTCSS tone — a sub-audible tone that opens the repeater's squelch. Find local repeaters at RepeaterBook. Tones are not privacy — everyone can still hear you.

Hams describe location with 4–6 characters like FN31pr: the world is divided into 18×18 'fields' (two letters), each into 10×10 'squares' (two digits), each into 24×24 'subsquares' (two letters). A 6-character grid pins you to about 3×4 miles — precise enough for VHF contacts and vague enough for privacy. Find yours by GPS at levinecentral.com/ham or many logging apps.

• Dual-band ham HT or GMRS handheld (+ programmed local repeaters & channels from this site)
• Spare batteries / USB battery pack + charging cable · AA battery shell if your HT takes one
• NOAA weather radio with SAME alerts (or WX channels programmed)
• Roll-up J-pole or whip upgrade antenna + adapter (SMA-F/SMA-M/BNC — know yours!)
• Laminated frequency card (print one from this site — it works offline too)
• Earpiece, notepad + pencil, headlamp
• Licenses: GMRS covers the family with no exam; the ham Technician exam is one weekend of study

In the US, receiving is nearly unrestricted: ham bands, marine, aviation, railroads (AAR channels, 160–161 MHz), NOAA satellites, the ISS, shortwave broadcasters, time stations. A $30 RTL-SDR dongle plus free software turns a laptop into an all-band receiver. Exceptions: you may not decrypt encrypted traffic or listen to cellular, and some states restrict scanner use in vehicles or in the commission of a crime. Sharing intercepted non-broadcast content can violate ECPA — listen, don't leak.

Day: 20m/17m/15m worldwide; 40m regional. Night: 40m/80m come alive for medium/long range; 20m may stay open west. High solar activity: 15m/12m/10m open worldwide with tiny power. Quick check: tune WWV at 5/10/15/20/25 MHz — whichever you hear tells you what's propagating. NVIS trick: 40m/80m with a low antenna gives reliable 0–300 mile coverage — the emergency-comms sweet spot.