T7

T7

The T7 section of the Technician test contains information on station equipment, common transmitter and receiver problems, antenna measurements and troubleshooting, basic repair and testing.

T7A

The T7A section covers station radios; receivers, transmitters, transceivers.

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T7A01

What is the function of a product detector?

Detect CW and SSB signals

T7A02

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What type of receiver is shown in Figure T6?

Single-conversion superheterodyne

T7A03

What is the function of a mixer in a superheterodyne receiver?

To shift the incoming signal to an intermediate frequency

T7A04

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What circuit is pictured in Figure T7, if block 1 is a frequency discriminator?

An FM receiver

T7A05

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What is the function of block 1 if Figure T4 is a simple CW transmitter?

Oscillator

T7A06

What device takes the output of a low-powered 28 MHz SSB exciter and produces a 222 MHz output signal?

Transverter

T7A07

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If Figure T5 represents a transceiver in which block 1 is the transmitter portion and block 3 is the receiver portion, what is the function of block 2?

A transmit-receive switch

T7A08

Which of the following circuits combines a speech signal and an RF carrier?

Modulator

T7A09

Which of the following devices is most useful for VHF weak-signal communication?

A multi-mode VHF transceiver

T7A10

What device increases the low-power output from a handheld transceiver?

An RF power amplifier

T7A11

Which of the following circuits demodulates FM signals?

Discriminator

T7A12

Which term describes the ability of a receiver to discriminate between multiple signals?

Selectivity

T7A13

Where is an RF preamplifier installed?

A. Between the antenna and receiver

T7B

The T7B section covers common transmitter and receiver problems; symptoms of overload and overdrive, distortion, interference, over and under modulation, RF feedback, off frequency signals; fading and noise; problems with digital communications interfaces.

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T7B01

What can you do if you are told your FM handheld or mobile transceiver is over deviating?

Talk farther away from the microphone

T7B02

What is meant by fundamental overload in reference to a receiver?

Interference caused by very strong signals

T7B03

Which of the following may be a cause of radio frequency interference?

Fundamental overload

Harmonics

Spurious emissions

All of these choices are correct

T7B04

What is themsnskslapsnsnjajstelephone from a nearby transmitter?

The telephone is inadvertently acting as a radio receiver

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T7B05

What is a logical first step when attempting to cure a radio frequency interference problem in a nearby telephone?

Install an RF filter at the telephone

T7B06

What should you do first if someone tells you that your station’s transmissions are interfering with their radio or TV reception?

Make sure that your station is functioning properly and that it does not cause interference to your own television

T7B07

Which of the following may be useful in correcting a radio frequency interference problem?

Snap-on ferrite chokes

Low-pass and high-pass filters

Band-reject and band-pass filters

All of these choices are correct

T7B08

What should you do if a "Part 15" device in your neighbor’s home is causing harmful interference to your amateur station?

Work with your neighbor to identify the offending device

Politely inform your neighbor about the rules that require him to stop using the device if it causes interference

Check your station and make sure it meets the standards of good amateur practice

All of these choices are correct

T7B09

What could be happening if another operator reports a variable high-pitched whine on the audio from your mobile transmitter?

Noise on the vehicle’s electrical system is being transmitted along with your speech audio

T7B10

What might be the problem if you receive a report that your audio signal through the repeater is distorted or unintelligible?

Your transmitter may be slightly off frequency

Your batteries may be running low

You could be in a bad location

All of these choices are correct

T7B11

What is a symptom of RF feedback in a transmitter or transceiver?

Reports of garbled, distorted, or unintelligible transmissions

T7B12

What does the acronym "BER" mean when applied to digital communications systems?

Bit Error Rate

T7C

The T7C section covers antenna measurements and troubleshooting; measuring SWR, dummy loads, feedline failure modes.

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T7C01

What is the primary purpose of a dummy load?

To prevent the radiation of signals when making tests

T7C02

Which of the following instruments can be used to determine if an antenna is resonant at the desired operating frequency?

An antenna analyzer

T7C03

What, in general terms, is standing wave ratio (SWR)?

A measure of how well a load is matched to a transmission line

T7C04

What reading on an SWR meter indicates a perfect impedance match between the antenna and the feedline?

1 to 1

T7C05

What is the approximate SWR value above which the protection circuits in most solidstate transmitters begin to reduce transmitter power?

2 to 1

T7C06

What does an SWR reading of 4

1 mean?

An impedance mismatch

T7C07

What happens to power lost in a feedline?

It is converted into heat

T7C08

What instrument other than an SWR meter could you use to determine if a feedline and antenna are properly matched?

Directional wattmeter

T7C09

Which of the following is the most common cause for failure of coaxial cables?

Moisture contamination

T7C10

Why should the outer jacket of coaxial cable be resistant to ultraviolet light?

Ultraviolet light can damage the jacket and allow water to enter the cable

T7C11

What is a disadvantage of "air core" coaxial cable when compared to foam or solid dielectric types?

It requires special techniques to prevent water absorption

T7D

The T7D section covers basic repair and testing; soldering, use of a voltmeter, ammeter, and ohmmeter.

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T7D01

Which instrument would you use to measure electric potential or electromotive force?

A voltmeter

T7D02

What is the correct way to connect a voltmeter to a circuit?

In parallel with the circuit

T7D03

How is an ammeter usually connected to a circuit?

In series with the circuit

T7D04

Which instrument is used to measure electric current?

An ammeter

T7D05

What instrument is used to measure resistance?

An ohmmeter

T7D06

Which of the following might damage a multimeter?

Attempting to measure voltage when using the resistance setting

T7D07

Which of the following measurements are commonly made using a multimeter?

Voltage and resistance

T7D08

Which of the following types of solder is best for radio and electronic use?

Rosin-core solder

T7D09

What is the characteristic appearance of a "cold" solder joint?

A grainy or dull surface

T7D10

What is probably happening when an ohmmeter, connected across a circuit, initially indicates a low resistance and then shows increasing resistance with time?

The circuit contains a large capacitor

T7D11

Which of the following precautions should be taken when measuring circuit resistance with an ohmmeter?

Ensure that the circuit is not powered