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Subel. L14a
27 questions
Subelement L14a

Establishing and Equipping a Station.

Section L14a

A low pass filter in an HF station is most effective when connected:

  • as close as possible to the antenna
  • midway between the transceiver and antenna
  • Correct Answer
    as close as possible to the transceiver output
  • as close as possible to the antenna tuner output

A 'Low-Pass' filter serves to reduce 'Harmonics' which can be generated in overdriven, improperly adjusted or malfunctioning AMPLIFIER stages, either the actual Power Amplifier in a transmitter or an external Linear Power Amplifier. Consequently, it should be inserted as close as possible to the transceiver or amplifier if one is used. The HF Station block diagram begins with: Transceiver, Linear Amplifier, Low-Pass Filter, SWR Bridge, Antenna Switch...

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

A low pass filter in an HF station is most effective when connected:

  • Correct Answer
    as close as possible to the linear amplifier output
  • as close as possible to the antenna
  • as close as possible to the antenna tuner output
  • as close as possible to the linear amplifier input

A 'Low-Pass' filter serves to reduce 'Harmonics' which can be generated in overdriven, improperly adjusted or malfunctioning AMPLIFIER stages, either the actual Power Amplifier in a transmitter or an external Linear Power Amplifier. Consequently, it should be inserted as close as possible to the transceiver or amplifier if one is used. The HF Station block diagram begins with: Transceiver, Linear Amplifier, Low-Pass Filter, SWR Bridge, Antenna Switch...

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

In designing an HF station, which component would you use to reduce the effects of harmonic radiation?

  • Dummy load
  • Antenna switch
  • SWR bridge
  • Correct Answer
    Low pass filter

A 'Low-Pass' filter serves to reduce 'Harmonics' which can be generated in overdriven, improperly adjusted or malfunctioning AMPLIFIER stages, either the actual Power Amplifier in a transmitter or an external Linear Power Amplifier. Consequently, it should be inserted as close as possible to the transceiver or amplifier if one is used. The HF Station block diagram begins with: Transceiver, Linear Amplifier, Low-Pass Filter, SWR Bridge, Antenna Switch...

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

Which component in an HF station is the most useful for determining the effectiveness of the antenna system?

  • Correct Answer
    SWR bridge
  • Antenna switch
  • Linear amplifier
  • Dummy load

The 'SWR Bridge' permits measuring the relative impedance match between the antenna system and the transceiver (SWR = Standing Wave Ratio). The HF Station block diagram begins with: Transceiver, Linear Amplifier, Low-Pass Filter, SWR Bridge, Antenna Switch...

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

Of the components in an HF station, which component would normally be connected closest to the antenna, antenna tuner and dummy load?

  • SWR bridge
  • Correct Answer
    Antenna switch
  • Transceiver
  • Low pass filter

The 'Antenna Switch' provides a convenient way to select a direct connection to an antenna, a connection through the 'Antenna Tuner' to other antennas or to the 'Dummy Load'. The HF Station block diagram begins with: Transceiver, Linear Amplifier, Low-Pass Filter, SWR Bridge, Antenna Switch, ...

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

Of the components in an HF station, which component would be used to match impedances between the transceiver and antenna?

  • Dummy load
  • SWR bridge
  • Correct Answer
    Antenna tuner
  • Antenna switch

The 'Antenna Tuner' provides variable impedance transformation: it can adapt the impedance of the antenna system (which changes with antenna dimensions and operating frequency) to the design impedance of the transceiver. The 'Antenna Tuner' permits using an antenna on a frequency or band other than the one for which it was designed.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

In an HF station, which component is temporarily connected in the tuning process or for adjustments to the transmitter?

  • Correct Answer
    Dummy load
  • SWR bridge
  • Low pass filter
  • Antenna tuner

The 'Dummy Load' (a resistor with a high power rating) dissipates RF energy as heat without radiating the RF on the air. Permits tests or adjustments without causing interference to other stations. The 'tuning process' refers to a manual procedure necessary for equipment with vacuum tube final Power Amplifiers where variable capacitors needed to be adjusted with each frequency change.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

In an HF station, the antenna tuner is usually used for matching the transceiver with:

  • mono-band Yagi type antennas
  • tri-band Yagi antennas
  • Correct Answer
    most antennas when operating below 14 MHz
  • most antennas when operating above 14 MHz

For example, on the 160 m band (1.8 MHz to 2.0 MHz), the band EDGES are 5% removed from the centre frequency of 1.9 MHz. On 80 m (3.5 MHz to 4.0 MHz), the edges are nearly 7% removed from the centre frequency of 3.75 MHz. On 20 m (14.0 MHz to 14.35 MHz), the edges are only 1.2% removed from the centre frequency of 14.175 MHz. Antennas present an acceptable standing wave ratio over a limited range of frequencies, the Antenna Tuner circumvents that limitation.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

In an HF Station, the antenna tuner is commonly used:

  • to tune low pass filters
  • Correct Answer
    with most antennas when operating below 14 MHz
  • with most antennas when operating above 14 MHz
  • to tune into dummy loads

For example, on the 160 m band (1.8 MHz to 2.0 MHz), the band EDGES are 5% removed from the centre frequency of 1.9 MHz. On 80 m (3.5 MHz to 4.0 MHz), the edges are nearly 7% removed from the centre frequency of 3.75 MHz. On 20 m (14.0 MHz to 14.35 MHz), the edges are only 1.2% removed from the centre frequency of 14.175 MHz. Antennas present an acceptable standing wave ratio over a limited range of frequencies, the Antenna Tuner circumvents that limitation.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

In an amateur digital radio system, the __________________ interfaces with the computer.

  • power supply
  • transceiver
  • Correct Answer
    input/output
  • antenna

The Digital Station block diagram: Input/Output, Computer, MODEM, Transceiver, Antenna.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

In an amateur digital radio system, the modem is connected to the ________.

  • input/output
  • Correct Answer
    computer
  • amplifier
  • antenna

The Digital Station block diagram: Input/Output, Computer, MODEM, Transceiver, Antenna.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

In an amateur digital radio system, the transceiver is connected to the ___________.

  • Correct Answer
    modem
  • computer
  • scanner
  • input/output

The Digital Station block diagram: Input/Output, Computer, MODEM, Transceiver, Antenna.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

In an amateur digital radio system, the audio connections of the modem/sound card are connected to the ___________.

  • antenna
  • Correct Answer
    transceiver
  • input/output
  • scanner

The Digital Station block diagram: Input/Output, Computer, MODEM, Transceiver, Antenna.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

In an amateur digital radio system, the modem function is often performed by the computer ____________.

  • serial port
  • Correct Answer
    sound card
  • keyboard
  • scanner

A "modem" is a modulator/demodulator: a device which turn computer digital communications into audible tones and vice-versa. Driven by computer programs, the 'sound card' in a computer can readily emulate that function.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

What do many amateurs use to help form good Morse code characters?

  • Correct Answer
    An electronic keyer
  • A key-operated on/off switch
  • A notch filter
  • A DTMF keypad

A 'Keyer' is an electronic circuit to which connects a 'Paddle'. The 'Keyer' issues dots and dashes in response to contact closures on the 'Paddle' by the operator. Dots and dashes are uniformly timed and spaced. The 'Paddle' relies on a side to side motion of the hand; it does not lead to fatigue as the traditional hand key does after a while.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

Where would you connect a microphone for voice operation?

  • Correct Answer
    To a transceiver
  • To a power supply
  • To an antenna switch
  • To an antenna

Remember your transmitter block diagrams: the Microphone connects to the Speech Amplifier, the first stage in a voice transmitter.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

What would you connect to a transceiver for voice operation?

  • A receiver audio filter
  • A terminal-voice controller
  • A splatter filter
  • Correct Answer
    A microphone

Remember your transmitter block diagrams: the Microphone connects to the Speech Amplifier, the first stage in a voice transmitter.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

Why might a dummy antenna get warm when in use?

  • Because it absorbs static electricity
  • Because it stores radio waves
  • Because it stores electric current
  • Correct Answer
    Because it changes RF energy into heat

The 'Dummy Load' (a resistor with a high power rating) dissipates RF energy as heat without radiating the RF on the air. Permits tests or adjustments without causing interference to other stations. The 'tuning process' (or 'loading') refers to a manual procedure necessary for equipment with vacuum tube final Power Amplifiers where variable capacitors needed to be adjusted.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

What is the circuit called which causes a transmitter to automatically transmit when an operator speaks into its microphone?

  • VCO
  • VFO
  • Correct Answer
    VOX
  • VXO

VOX = "Voice Operated Transmit". VFO = "Variable Frequency Oscillator". [ the other two are beyond the scope of a Basic license. ]

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

What is the reason for using a properly adjusted speech processor with a single-sideband phone transmitter?

  • It reduces average transmitter power requirements
  • It reduces unwanted noise pickup from the microphone
  • It improves voice frequency fidelity
  • Correct Answer
    It improves signal intelligibility at the receiver

The 'Speech Processor' makes for more average power being packed in the transmitted sideband. 'Speech processing' is raising the average amplitude of the audio input from the microphone closer to an acceptable peak value: i.e., make every passage of the spoken words equally loud. THE AVERAGE can be increased but not the PEAK. Too much speech processing leads to distortion and possibly driving the Linear Power Amplifier with too large a signal (overdriving).

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

If a single-sideband phone transmitter is 100% modulated, what will a speech processor do to the transmitter's power?

  • It will decrease the peak power output
  • It will decrease the average power output
  • Correct Answer
    It will add nothing to the output Peak Envelope Power (PEP)
  • It will increase the output PEP

The 'Speech Processor' makes for more average power being packed in the transmitted sideband. 'Speech processing' is raising the average amplitude of the audio input from the microphone closer to an acceptable peak value: i.e., make every passage of the spoken words equally loud. THE AVERAGE can be increased but not the PEAK. Too much speech processing leads to distortion and possibly driving the Linear Power Amplifier with too large a signal (overdriving).

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

When switching from receive to transmit:

  • the receiving antenna should be connected
  • the power supply should be off
  • Correct Answer
    the receiver should be muted
  • the transmit oscillator should be turned off

Switching from receive to transmit supposes FOUR actions: disconnect the antenna from the receiver, connect the antenna to the transmitter, silence the receiver and activate the Power Amplifier in the transmitter. A 'Relay' (a multiple-contact electrically-driven switch) frequently performs the antenna changeover an the enabling/disabling of the transceiver sections.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

A switching system to enable the use of one antenna for a transmitter and receiver should also:

  • ground the antenna on receive
  • switch between meters
  • disconnect the antenna tuner
  • Correct Answer
    disable the unit not being used

Switching from receive to transmit supposes FOUR actions: disconnect the antenna from the receiver, connect the antenna to the transmitter, silence the receiver and activate the Power Amplifier in the transmitter. A 'Relay' (a multiple-contact electrically-driven switch) frequently performs the antenna changeover an the enabling/disabling of the transceiver sections.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

An antenna changeover switch in a transmitter-receiver combination is necessary:

  • Correct Answer
    so that one antenna can be used for transmitter and receiver
  • to change antennas for operation on other frequencies
  • to prevent RF currents entering the receiver circuits
  • to allow more than one transmitter to be used

Switching from receive to transmit supposes FOUR actions: disconnect the antenna from the receiver, connect the antenna to the transmitter, silence the receiver and activate the Power Amplifier in the transmitter. A 'Relay' (a multiple-contact electrically-driven switch) frequently performs the antenna changeover an the enabling/disabling of the transceiver sections.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

Which of the following components could be used as a dynamic microphone?

  • Correct Answer
    Loudspeaker
  • Crystal earpiece
  • Resistor
  • Capacitor

A 'Dynamic Microphone' is built around a membrane, a voice coil and a magnet: sound waves cause the membrane to vibrate, the voice coil, attached to the membrane, moves in and out of a magnetic field thus producing a tiny electrical signal corresponding to the voice. Loudspeaker employ the reverse principle: an audio signal applied to the voice coil moves the membrane to reproduce sound waves.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

What device might allow use of an antenna on a band it was not designed for?

  • A low pass filter
  • A high pass filter
  • Correct Answer
    An antenna tuner
  • An SWR meter

The 'Antenna Tuner' permits using an antenna on a frequency or band other than the one for which it was designed. The 'SWR Meter' measures antenna system efficiency. The 'Low-Pass Filter' reduces 'Harmonic Radiation'. The 'High-Pass Filter' protects TV receivers from being overloaded by HF transmissions.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

What does an antenna tuner do?

  • Correct Answer
    It matches a transceiver to a mismatched antenna system
  • It helps a receiver automatically tune in stations that are far away
  • It switches an antenna system to a transmitter when sending, and to a receiver when listening
  • It switches a transceiver between different kinds of antennas connected to one transmission line

The 'Antenna Tuner' provides variable impedance transformation: it can adapt the impedance of a the antenna system (which changes with antenna dimensions and operating frequency) to the design impedance of the transceiver. The 'Antenna Tuner' permits using an antenna on a frequency or band other than the one for which it was designed.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

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