T2B

Repeater operation, tones and Q signals

Use reverse, CTCSS, DTMF and DMR settings, solve common access problems, and read the common Q signals.

14 pool questions1 on the exam

Syllabus: VHF/UHF operating practices: FM repeater, simplex, reverse splits; Access tones: CTCSS, DTMF; DMR operation; Resolving operating problems; Q signals

Hear the repeater but can't get in? Check three settings

Reverse swaps your radio's receive and transmit frequencies, so you listen on the repeater's input.

Example 2 m pair. Normal: you hear the OUTPUT and transmit on the INPUT.

Hearing a repeater only proves your receive side works. Access can still fail from an improper offset, the wrong CTCSS tone, or the wrong DCS code. Any of them will do it.

RememberReverse = listen on the input. No access? Offset, CTCSS, DCS.

Tones open the door: CTCSS and DTMF

CTCSS: a tone below the voice band, sent with your voice, opens the repeater's squelch.

Squelch mutes the receiver when no signal is present. CTCSS is a sub-audible tone sent with your voice to open the squelch.

DTMF = two simultaneous audio tones per key. Tap a key.

DTMF (touch-tone) sends two simultaneous tones per key, used for signaling a repeater.

Memory hookCTCSS: one quiet tone under the voice. DTMF: two tones at once (Dual-Tone).

DMR: color code gets you in, talkgroup picks the chat

Color code = access. Talkgroup = which conversation. Both are programmed into your radio.

The color code is an access code programmed into your radio to use a specific repeater. A talkgroup organizes traffic so you hear only the groups you want. To join one, program its ID into your radio.

RememberColor code = access. Talkgroup = which conversation.

Linked repeaters share one signal; simplex spares them

Linked: one repeater hears you, all of them transmit. Simplex: within range, leave the repeater alone.

In a linked repeater network, a signal received by one repeater is transmitted by all of them. Simplex channels are set aside so stations within range can talk without tying up a repeater.

RememberClose enough? Go simplex.

Fix problems with the simple cause first

Problem	Cause or action
Audio drops out on voice peaks	Talking too loudly (too much FM deviation). Speak softer.
Two stations on one frequency interfere	Negotiate continued use. No one has automatic rights.
Hear repeater, can't access it	Offset, CTCSS tone, or DCS code

Q signals: three-letter shorthand

Q signal	Meaning
QRM	Interference from other stations
QRN	Static, natural noise
QSY	Changing frequency
QSB	Fading signal
QTH	My location
QSL	Message received

Memory hookQRM = Man-made interference (other stations). QRN = Natural noise. QSY = "Shift to a new frequency".

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Compendium articles on the ideas in this lesson, beyond what the exam asks.

Check what stuck

Practise the 14 pool questions for this group. Answers are shuffled, and every one comes with a one-line "why".

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