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Repeaters

A repeater is a radio on a tall place — a tower, a skyscraper, a hilltop — that listens on one frequency and instantly retransmits what it hears on another, at high power from high up. Your 5-watt handheld can't reach across the city; the repeater hears your whisper and shouts it across the county.

This is the beginner's superpower. Most first contacts happen through repeaters, most clubs run weekly nets on them, and emergency traffic flows through them. Understanding three settings — offset, tone, and simplex — covers 90% of repeater use.

How it works

A repeater uses two frequencies:

  • The input — what the repeater listens on (what you transmit on).
  • The output — what the repeater transmits on (what you listen on).

The gap between them is the offset. It's fixed by convention per band, so you usually just set "plus" or "minus" and the radio does the math:

Band Standard offset
2 m (144–148 MHz) ±600 kHz
70 cm (420–450 MHz) ±5 MHz

So a 2-meter repeater with output 146.94 MHz and a minus offset listens for you on 146.34 MHz. Publish a repeater as "146.94, minus offset" and every ham knows both frequencies.

The tone: CTCSS / PL

Many repeaters require a sub-audible tone — a very low frequency hum your radio adds to your transmission, too low to hear but the repeater listens for it. This is CTCSS (Continuous Tone-Coded Squelch System), which Motorola branded as PL (Private Line). Same thing.

The tone keeps the repeater from waking up for noise, distant stations, or interference. When a repeater listing says "146.94, minus, 103.5," that 103.5 Hz is the tone your radio must send. Set the wrong tone (or none) and the repeater ignores you completely — the single most common beginner problem (see Troubleshooting).

Check: Find your local repeaters before you buy a radio. Search "repeater directory" plus your city, or check a national repeater database. Note each repeater's output frequency, offset direction, and tone — you'll program these into your radio on day one.

Simplex: talking direct

Simplex means transmitting and receiving on the same frequency — radio to radio, no repeater. Range is whatever your antennas and terrain allow: a mile or two between handhelds, much more from a hilltop.

Two simplex frequencies are set aside nationally as calling frequencies — places to meet before moving elsewhere:

  • 146.52 MHz — the national 2 m simplex calling frequency
  • 446.000 MHz — the national 70 cm simplex calling frequency

Etiquette: call, make contact, then move off to another simplex frequency so the calling channel stays clear. Think of it as the lobby, not the living room.

Nets and etiquette

A net is a scheduled on-air gathering on a repeater — weekly club check-ins, weather nets, emergency drills. Joining one is the fastest way to become part of the local community.

Repeater etiquette, the short version:

  1. Listen first. Spend time hearing how the repeater is used before you transmit. Every repeater has its own culture.
  2. Keep transmissions short. Leave pauses between transmissions so others (including emergency traffic) can break in.
  3. ID per the rule. Callsign at the end of your contact and every 10 minutes (§97.119) — same as everywhere else.
  4. Don't kerchunk. Keying the mic just to hear the repeater's courtesy beep, without identifying, is the classic beginner faux pas. If you're testing, say your callsign: "KI5ABC, testing."
  5. Emergency traffic has absolute priority. If someone declares an emergency, clear the frequency.

Check: Listen to a local repeater for a week before transmitting. You'll absorb the rhythm — how people call, how nets run check-ins, how long the pauses are — better than any written description.

Next: Your First Radio — what to buy (and what the categories actually mean).