T1 · Published 26 October 2026 · By The Ham Desk

On the Air: Phonetics, Repeaters, Nets and Emergencies

Everything in this unit is convention rather than electronics: the words amateurs use to spell their call signs, the numbers they exchange to describe a signal, and the procedures that keep a repeater usable when a hundred people want to use it at once.

Band 2 m
Study time 15
Level Recall
questions 10

Waveform and antenna diagram for Operating Practice — Operating Practice — waveform overlay and radiation pattern

Pre-flight briefing

Saying your call sign so it survives the trip

The ITU phonetic alphabet is the standard way to spell a call sign over a noisy channel: Alpha, Bravo, Charlie, Delta, Echo, Foxtrot, Golf, Hotel, India, Juliett, Kilo, Lima, Mike, November, Oscar, Papa, Quebec, Romeo, Sierra, Tango, Uniform, Victor, Whiskey, X-ray, Yankee, Zulu. The version in Part 97 is exactly this list, and using it rather than improvised words is what lets a station with a weak signal be copied the first time.

Identification itself is a rule, not a courtesy: section 97.119 requires the station to transmit its assigned call sign at least every ten minutes during a communication and again at the end of it, and any transmission that does not identify is a violation regardless of how short it is.

Repeaters, codes and the RST system

A repeater receives on one frequency and simultaneously retransmits on another, which is what extends the usable range of a handheld or mobile far beyond line of sight. Because a repeater is a shared resource with one channel, etiquette matters: keep transmissions short, leave a pause between them so someone with an emergency can break in, and let the repeater's courtesy tone mark the end before you start.

Dual-tone multi-frequency tones - the same eight tones a telephone keypad uses - are sent over the air to control repeater functions such as turning a link on, switching to another repeater, or accessing an autopatch. A repeater's control operator may also shut it down remotely, which is why the control operator, not the users, is responsible for what the repeater transmits.

The RST system gives three numbers, or two for voice: readability on a scale of 1 to 5, signal strength from 1 to 9, and tone from 1 to 9 on CW. A report of 59 means perfectly readable and very strong; on CW a 599 adds a pure tone. RST numbers are subjective - two operators will report the same signal differently - and they exist to give the other station useful information rather than a measurement.

Nets, calls and emergencies

CQ means 'calling any station': it is an invitation for anyone listening to answer, usually followed by your call sign and the band you are on. QSL means 'I acknowledge receipt' and in practice confirms a contact, while 73 is the standard sign-off meaning best regards - it is not a plural and does not need an S.

A directed net has a net control station that runs the traffic, and the procedure for joining is simple: listen for a while to learn the rhythm, wait for net control to ask for check-ins, then give your call sign and nothing else. Breaking into a net mid-exchange is only appropriate for emergency traffic, and the recognised way to announce that is to say 'emergency' or 'priority' between transmissions.

For a genuine distress situation the international signal is MAYDAY, spoken three times if conditions allow, and on CW it is SOS. Naming the emergency gives your message priority over everything else on the frequency, and any station that hears it is expected to stop transmitting and assist.

Terms you must be able to define
Term	What the examiner wants to hear
ITU phonetic alphabet	The standard spelling alphabet: Alpha, Bravo, Charlie and so on.
RST	Readability, strength, tone - the amateur signal report system.
Courtesy tone	The short beep a repeater sends when a transmission ends.
DTMF	Dual-tone multi-frequency signalling, used for repeater control and autopatch.
MAYDAY	The international spoken distress signal, giving the call priority over all other traffic.

Question deck 10 questions

T6A01 Recall

Which word is used in the ITU phonetic alphabet for the letter G?

T6A02 Recall

What do the letters RST stand for in a signal report?

T6A03 Recall

What does the Q signal QSL mean?

T6A04 Recall

What does the number 73 mean in amateur communication?

T6A05 Core

What is the main purpose of a repeater?

T6A06 Core

What is the proper way to join a directed net?

T6A07 Recall

What does the procedural signal CQ mean?

T6A08 Core

Which spoken signal indicates a life-threatening emergency?

T6A09 Stretch

What are DTMF tones used for in amateur radio?

T6A10 Core

How often must a station identify itself during a communication?

Reference sheet

The explanations for all ten questions sit on this sheet. Pick an answer on the left and the matching card lights up.

T6A01 Explanation 1

Key A — Golf

The ITU list is standardised internationally and appears in Part 97: Golf for G, Hotel for H, India for I. Improvised words work only if the other operator happens to know them, which is precisely what a standard alphabet avoids.

Rule 47 CFR §97.119(b)(2) - ITU phonetics

T6A02 Explanation 2

Key D — Readability, strength, tone

Readability runs 1 to 5, strength 1 to 9, and tone 1 to 9 on CW only. Voice reports use just the first two numbers, so a strong, perfectly readable FM signal is reported as 59.

Rule Operating practice - signal reports

T6A03 Explanation 3

Key C — I acknowledge receipt, or I confirm the contact

QSL acknowledges receipt. Hams also use it for the card that confirms a contact, and 'QSL via the bureau' means the card will travel through a national QSL bureau rather than by post.

Rule Operating practice - Q signals

T6A04 Explanation 4

Key B — Best regards

73 is the standard sign-off, meaning best regards. It is singular in origin - a telegrapher's shorthand - so '73s' is not needed, though you will hear it on the air almost every day.

Rule Operating practice - procedural signals

T6A05 Explanation 5

Key A — To receive on one frequency and retransmit on another so stations can communicate beyond line of sight

By putting a receiver and transmitter, usually several hundred feet up on a tower, between two stations, a repeater turns a hill-limited path into a reliable one. It does not amplify in the sense of making your signal stronger at the far end from nowhere - it simply gives both stations a high, clear vantage point.

Rule 47 CFR §97.205 - repeater stations

T6A06 Explanation 6

Key D — Listen until net control calls for check-ins, then give your call sign

A directed net is a managed conversation, and net control decides when stations may transmit. Checking in at the wrong moment disrupts the net's business, which is often emergency or public service traffic moving in a strict order.

Rule 47 CFR §97.101(b) - cooperation and net discipline

T6A07 Explanation 7

Key C — Calling any station

CQ is a general invitation to any station that can hear you. If you want one particular station you name it: 'W1ABC, this is K2DEF' rather than CQ.

Rule Operating practice - calling

T6A08 Explanation 8

Key B — MAYDAY

MAYDAY is the international distress signal and carries absolute priority over all other traffic on the frequency. On CW the equivalent is SOS. The amateur rules also allow any means available to attract attention in a genuine emergency, including transmitting outside the usual bands.

Rule 47 CFR §97.403 - safety of life and protection of property

T6A09 Explanation 9

Key A — Sending control commands to a repeater, such as activating a link or an autopatch

DTMF is the touch-tone signalling used in telephony, and repeaters repurpose it so users can switch functions by keypad. Note that encryption is prohibited in the amateur service, and automatic identification has its own rules under which only specific digital codes may be used.

Rule 47 CFR §97.205(e) - repeater control and §97.309 digital codes

T6A10 Explanation 10

Key A — At least every ten minutes during the contact, and at the end of it

Section 97.119 sets the ten-minute mark and the end of the communication. Because it applies to any transmission, a brief test or a quick call on a repeater still needs your call sign - and giving it is how the other station knows who they are talking to.

Rule 47 CFR §97.119(a) - station identification

How to use this unit

Work the ten questions in one sitting with the reference sheet covered, then uncover it and read every explanation - including the ones you got right. The wording of the real exam is different, so learn the reasoning rather than the answer letters.