Radio Programming 5 — Finding Repeaters & Understanding the Settings
Find local repeaters, read a listing correctly, and understand every setting before you program it.
~20 min · 0/11 required steps
What a repeater actually does
A repeater is a radio receiver and transmitter that listens on one frequency and simultaneously retransmits what it hears on a different frequency — usually from a hilltop, water tower, or tall building. It extends the range of low-power handhelds dramatically. A 5-watt HT that can only reach 2 miles simplex might cover 50+ miles through a well-placed repeater. Because the repeater transmits and receives at the same time on different frequencies, your radio must be programmed to listen on one frequency and transmit on another. That difference is the offset.
Reading a RepeaterBook listing
Every RepeaterBook listing includes the same core fields: Output frequency — the frequency the repeater transmits on. This is what you listen to. It's the main frequency shown in listings. Input frequency — the frequency the repeater listens on. This is what you transmit on. Often shown as the output ± the offset instead of a separate number. Offset — the difference between input and output. Sign (+ or –) tells direction. On 2 meters: standard offset is ±600 kHz. On 70 cm: standard offset is ±5 MHz. PL tone / CTCSS / CTCSS Tone — the sub-audible tone your radio must transmit to open the repeater's squelch gate. Without it, the repeater hears you but won't retransmit. Notes / Status — many listings include coverage area, club affiliation, linked systems, or operational notes. Worth reading before assuming a repeater is active.
Finding local repeaters — RepeaterBook workflow
Offset direction — the easy way to remember it
On 2 meters in the US, the standard is: if the output is below 147.000 MHz, the offset is negative (–). If the output is 147.000 or above, the offset is positive (+). This is the standard plan — but always verify against the actual RepeaterBook listing since non-standard offsets exist. On 70 cm, most repeaters use a +5 MHz offset (you transmit 5 MHz above the output). Again — verify against the listing.
PL tones explained — what they are and what they're not
PL tone (also called CTCSS, or sub-audible tone) is a continuous low-frequency audio tone your radio transmits underneath your voice. The repeater's squelch gate is set to only open for signals carrying the correct tone — everything else is ignored. PL tones are NOT privacy. Anyone can hear your conversation whether or not they have the tone. The tone only controls whether the repeater retransmits you — not whether others can listen. Common PL tones you'll see: 67.0, 88.5, 100.0, 107.2, 123.0, 131.8, 136.5, 141.3, 146.2. Always use whatever tone the listing specifies. Using no tone (or the wrong tone) means the repeater hears you but won't key up. DCS (Digital Coded Squelch) serves the same purpose but uses a digital code instead of an audio tone. Some repeaters use DCS; some use both CTCSS and DCS; some use neither.
Bandwidth — narrow vs. wide
Modern repeaters and radios operate in either narrowband (12.5 kHz) or wideband (25 kHz) mode. A mismatch between your radio's setting and the repeater's mode causes distorted, garbled, or very quiet audio — on both transmit and receive. Most modern US repeaters are narrowband (12.5 kHz). If a RepeaterBook listing doesn't specify, assume narrowband. In CHIRP, the Mode column controls this — NFM is narrow FM, FM is wide FM.
Testing a newly programmed repeater
Why this matters
Programming a wrong frequency does nothing. Programming the right frequency with the wrong offset means you're transmitting on a frequency nobody expects. Programming the wrong PL tone means the repeater ignores you. Understanding what each setting does — not just which number to enter — means you can troubleshoot any programming problem in the field without guessing.