Correct answer: B — your signal does not have enough strength to operate the repeater

VHF repeaters use a squelch (or CTCSS/DCS access tone) system to open the receiver only when an adequate signal is present. When a mobile station "drops out," it means the received signal at the repeater falls below the squelch threshold — often due to terrain, buildings, or distance — and the repeater briefly stops re-transmitting. The other station hears the audio cut in and out.

• A — signal drifting lower in frequency: Frequency drift causes a different problem (off-channel reception or tone decode failure) but would not typically be described as "dropping out."
• C — voice is too low-pitched to be understood: Pitch affects intelligibility but has nothing to do with repeater access or signal strength; this is not what "dropping out" means in repeater operation.
• D — not speaking loudly enough: Microphone level affects audio deviation, but "dropping out" specifically describes the repeater losing the carrier/access signal entirely, not an audio level problem.

Therefore, "dropping out" through a repeater means your transmit signal is too weak to consistently key up (open) the repeater, causing intermittent loss of retransmission.

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Correct answer: C — a large group of stations all calling the same DX station

A "pileup" occurs when a rare or distant station (DX) comes on air and many operators simultaneously try to make contact with it. The result is a large number of stations transmitting at once, creating a chaotic "pile" of signals on the frequency. Pileups are a common feature of DX operating and contesting, and skilled operators learn techniques to work through them efficiently (such as operating "split" — listening on one frequency while transmitting on another).

• A — an old, worn-out radio: Incorrect; this is informal slang unrelated to any recognised amateur radio term.
• B — another name for a junkbox: Incorrect; a "junkbox" refers to a collection of spare electronic components, not a pileup.
• D — a type of selenium rectifier: Incorrect; selenium rectifiers are an older power-supply component and have no connection to the term "pileup."

Therefore, a pileup is the well-known operating situation where many stations compete to contact the same sought-after DX station simultaneously.

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Correct answer: key-down changes the station to transmit, key-up to receive

Break-in keying allows a CW station to automatically switch between transmitting and receiving as the Morse key is operated.

When the key is pressed (key-down), the transmitter is activated.
When the key is released (key-up), the station immediately returns to receive mode.

This allows the operator to hear incoming signals between transmitted characters or words.

• It is not related to theft or unauthorised entry.
• It is not specifically for emergency operation.
• It does not refer to erratic keying by another station.

Therefore, break-in keying means key-down transmits and key-up receives.

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Correct answer: listens on a frequency 600 kHz higher than its designated frequency

A repeater’s designated frequency normally refers to its output (transmit) frequency.

With a positive \(600\ \mathrm{kHz}\) split, the repeater’s input frequency is:

\[ f_{\text{input}} = f_{\text{output}} + 600\ \mathrm{kHz} \]

This means it listens on a frequency \(600\ \mathrm{kHz}\) higher than the frequency on which it transmits.

• Transmitting \(600\ \mathrm{kHz}\) higher would describe the opposite shift.
• A repeater does not transmit on two frequencies simultaneously.
• The split is unrelated to modulation type or bandwidth.

Therefore, a repeater with a positive \(600\ \mathrm{kHz}\) split listens on a frequency 600 kHz higher than its designated frequency.

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Correct answer: plus 600 kHz above 147 MHz, minus 600 kHz on or below 147 MHz

Repeaters must transmit and receive on different frequencies so they can operate simultaneously without the transmitter overloading the receiver.

The frequency separation (offset) must be:

• large enough to allow practical duplexer filtering between transmit and receive paths
• small enough to keep both frequencies within the 2 m amateur band

In New Zealand, a standard offset of \(600\ \mathrm{kHz}\) has been adopted by band planning authorities to balance these requirements.

The change in shift direction at \(147\ \mathrm{MHz}\) is a coordination measure to prevent repeater input frequencies from overlapping other repeater output frequencies within the band.

• Reversing the direction of the \(600\ \mathrm{kHz}\) offset would cause repeater input/output frequency conflicts within the band plan.
• A \(5\ \mathrm{MHz}\) offset is used on other amateur bands (such as 70 cm), not on 2 metres.

Therefore, the standard 2 metre repeater split in New Zealand is \(\pm 600\ \mathrm{kHz}\) with the changeover at 147 MHz.

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Correct answer: 5 MHz

On the 70 cm amateur band (around \(430\text{–}440\ \mathrm{MHz}\) in New Zealand), repeaters use a standard frequency split of \(\pm 5\ \mathrm{MHz}\) between the transmit and receive frequencies. This separation provides sufficient isolation to prevent the repeater transmitter from desensitising its own receiver and allows practical filtering.

• 600 kHz is the standard repeater split used on the 2 metre band, not on 70 cm.
• 1 MHz is not a standard repeater offset in New Zealand.
• 2 MHz is also not a standard allocation for 70 cm repeater operation.

Therefore, the standard frequency offset for 70 cm repeaters in New Zealand is ±5 MHz.

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Correct answer: minimum reflected power

An SWR bridge measures how much power is reflected back from the antenna due to impedance mismatch.

When adjusting an antenna matching unit, the goal is to match the antenna impedance to the transmission line so that:

• as much power as possible is delivered to the antenna
• as little power as possible is reflected back toward the transmitter

This corresponds to the lowest SWR and minimum reflected power.

• Maximum reflected power indicates poor matching.
• Equal reflected and transmitted power indicates a severe mismatch.
• Minimum transmitted power would result in poor radiation.

Therefore, you should adjust for minimum reflected power.

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Correct answer: A — inhibits the audio output unless a station is being received

Squelch (also called muting) circuitry monitors the received signal level or noise level at the discriminator output of a VHF FM receiver. When no signal is present, the receiver produces a loud rushing noise. The squelch circuit detects this "noise energy" and mutes (silences) the audio output until a signal above the squelch threshold arrives — at which point the audio is unmuted and the received transmission is heard.

• B is wrong — compressing voice signals to improve intelligibility is the function of an audio compressor or speech processor, not squelch.
• C is wrong — reducing burst noise from lightning is a form of noise blanking, a separate circuit entirely.
• D is wrong — reducing noise on incoming signals would be noise reduction or filtering; squelch does not clean up a received signal, it simply gates the audio on or off.

Therefore, squelch circuitry acts as an audio gate that keeps the speaker silent between transmissions, only opening when a valid signal is received.

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Correct answer: indicates relative incoming signal strengths

An S-meter (signal strength meter) shows the strength of the received signal.

It provides:

• a relative indication (not absolute calibrated power)

• a scale (e.g., S1 to S9, sometimes with dB over S9)

• It is not used to set squelch.

• It does not measure SWR.

• It does not indicate battery voltage.

Therefore, it indicates relative incoming signal strengths.

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Correct answer: a series of nationwide amateur radio linked repeaters in the 70 cm band

In New Zealand, the National System refers to a network of linked amateur radio repeaters, primarily operating on the 70 cm band. These repeaters are interconnected so that a transmission into one repeater can be heard across much of the country.

The system is used for:

• routine long-distance amateur communication

• coordinating nationwide activities and events

• providing wide-area coverage when local repeaters are insufficient

• the legal licensing standard of Amateur operation in New Zealand refers to regulatory documents and certificates, not the repeater network.

• the official New Zealand repeater band plan defines frequency usage and coordination, not a specific linked repeater system.

• a nationwide emergency communications procedure may make use of the National System, but the system itself is the repeater network, not the procedure.

Therefore, the National System is a series of nationwide amateur radio linked repeaters in the 70 cm band.

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Correct answer: ignition noise

A noise blanker is designed to suppress short-duration, high-amplitude impulse noise. It detects sharp noise spikes and momentarily mutes the receiver so the impulse does not reach the audio output.

Typical sources of this type of noise include vehicle ignition systems, electric motors, and switching devices, which generate brief repetitive pulses.

• 50 Hz power supply hum is a continuous low-frequency signal and is not impulsive, so a noise blanker is ineffective.
• noise originating from the mixer stage is internal receiver noise and cannot be removed by blanking the incoming signal.
• noise originating from the RF stage is also internal and broadband, not short impulse noise.

Therefore, a noise blanker is most effective at reducing ignition noise.

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Correct answer: A — change from receiving to transmitting using the sound of the operator's voice

VOX stands for Voice-Operated Switching (or Voice-Operated Transmit). When the operator speaks into the microphone, the audio level triggers a relay or electronic switch that automatically keys the transmitter. When speech stops, the radio returns to receive mode after a short hold-down delay. This allows hands-free operation without pressing a push-to-talk (PTT) button.

• B is wrong — "voice operated crystal" is not a real component; no crystal is involved in VOX operation.
• C is wrong — VOX has nothing to do with external speakers or volume-controlled audio routing.
• D is wrong — "variable oscillator crystal" is a meaningless term; VOX does not control the VFO or any oscillator circuit.

Therefore, a VOX unit switches the transceiver from receive to transmit automatically in response to the operator's voice, enabling convenient hands-free operation.

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Correct answer: B — voice operated transmit

VOX is a circuit found in transceivers that automatically switches the radio from receive to transmit when the operator speaks into the microphone. When audio is detected above a set threshold, the PTT (push-to-talk) function is triggered without the operator needing to press a button. A sensitivity control and a hang-time (delay) control are typically provided so the radio doesn't drop back to receive between words.

• A — volume operated extension speaker: Incorrect; "volume" and "extension speaker" have no relation to the transmit-switching function VOX performs.
• C — variable oscillator transmitter: Incorrect; VOX has nothing to do with oscillator design or frequency generation.
• D — voice operated expander: Incorrect; an expander is an audio dynamics-processing device, unrelated to the transmit-switching meaning of VOX.

Therefore, VOX stands for voice operated transmit, describing a hands-free automatic transmit-switching function triggered by the operator's voice.

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Correct answer: C — receiver incremental tuning

RIT is a control found on many HF transceivers that allows the operator to shift the receiver frequency slightly (typically a few kHz) without moving the transmitter frequency. This is useful when a station you are working is slightly off your transmit frequency — you can tune your receiver to match their signal while keeping your transmit frequency unchanged, avoiding disruption to the contact and the band.

• A. receiver interference transmuter — not a real term; "transmuter" has no meaning in this context.
• B. range independent transmission — a fabricated phrase unrelated to transceiver controls.
• D. random interference tester — not a real term; RIT has nothing to do with interference testing.

Therefore, RIT — receiver incremental tuning — is a practical transceiver feature that lets you offset your receive frequency independently of your transmit frequency.

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RIT - "Receiver Incremental Tuning". A transceiver is usually a receiver and transmitter combination sharing a lot of common circuits - such as the various oscillators that determine its operating frequency. RIT provides a tuning facility so the receiver can be separately tuned for a few kHz each side of the transmit frequency, hence giving independent control over the receive frequency.

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Correct answer: A — transmit on one frequency and receive on another

The "split frequency" (or "split operation") function allows a transceiver to use separate VFOs — one for transmitting and one for receiving. This is commonly used when working DX stations or repeaters that listen on a different frequency from the one they transmit on. For example, a DX station may transmit on 14.225 MHz but ask callers to transmit "up 5", meaning callers transmit on 14.230 MHz while listening on 14.225 MHz. Split operation makes this straightforward.

• B is incorrect — monitoring two frequencies simultaneously through one loudspeaker describes a dual-watch or dual-receive function, not split operation.
• C is incorrect — monitoring two frequencies through two separate loudspeakers is again a dual-watch/dual-receive feature, unrelated to split frequency.
• D is incorrect — receiving CW and SSB simultaneously on the same frequency is not a standard transceiver function and has nothing to do with split operation.

Therefore, "split frequency" specifically means the transmit and receive frequencies are set independently, allowing the operator to transmit on one frequency while listening on another.

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ALC - "Automatic Level Control". Just as we had AGC in a receiver, this is a similar thing for transmitters, usually for the linear amplifiers used in SSB transmitters. Its purpose is to prevent over-driving the linear amplifier stages especially the final amplifier. It may also permit the peaks of an SSB signal to be limited in amplitude to enable an increase in the mean output power of the transmitter to improve the relative signal level at a distant receiver. This function can also involve processing the audio in the transmitter, known as "compression" .

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Correct answer: minimise the adjustments needed to the receiver gain control knobs

AGC (Automatic Gain Control) automatically adjusts the receiver’s gain in response to changes in received signal strength.

This keeps the audio output at a relatively constant level despite variations in signal strength, reducing the need for manual gain adjustments.

• It does not expand audio gain.
• It does not generate amplitude.
• It is not related to limiting oscillator output.

Therefore, the AGC circuit is used to minimise the adjustments needed to the receiver gain control knobs.

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Correct answer: D — vary the gain of the radio frequency and audio frequency amplifier stages independently

A receiver contains multiple amplifier stages operating at different points in the signal chain. The RF gain control adjusts the amplification applied to the incoming radio-frequency signal (before and through the mixer/IF stages), while the AF gain control adjusts the amplification of the recovered audio signal after detection. Having both controls gives the operator fine command over signal handling: for example, reducing RF gain can prevent overloading on strong signals, while AF gain sets the listening volume to a comfortable level.

• A is wrong — gain controls do not alter receiver or transmitter frequencies; that is the function of a tuning dial or VFO.
• B is wrong — AF gain is a single overall audio level control, not a split low/high frequency (tone) control; "bass and treble" are tone controls, not gain controls.
• C is wrong — "real" and "absolute" frequencies are not meaningful receiver parameters; this is a fabricated distractor.

Therefore, RF and AF gain controls independently adjust the amplification at the radio-frequency and audio-frequency stages of the receiver, giving the operator precise control over signal strength and listening volume.

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Correct answer: A — Push to talk

PTT (Push to Talk) refers to the control method used in radio transceivers where pressing a button (or switch) switches the radio from receive mode to transmit mode. Releasing the button returns the radio to receive. This is the standard operating method for voice communications on amateur, commercial, and emergency radio systems. The PTT switch is typically located on the microphone or the radio body.

• B. Piezo-electric transducer transmitter — Not a real radio term; "piezo-electric transducer" refers to a type of sensor/speaker element, unrelated to the PTT acronym.
• C. Phase testing terminal — Not a recognised radio or electronics term; an invented distractor.
• D. Phased transmission transponder — A transponder is a device that receives and retransmits signals automatically; this has no connection to the PTT acronym or function.

Therefore, PTT simply means push to talk — the momentary switch action that keys a transmitter for voice operation.

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