W4CA

Roanoke Valley Amateur Radio Club

T-4

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Subelement T4

Amateur radio practices and station set up

 

A computer maybe used as part of an amateur radio station for logging contacts and contact information, for sending and/or receiving CW and generating and decoding digital signals. A regulated power supply prevents voltage fluctuations from reaching sensitive circuits in communications equipment. An in-line SWR meter is connected in series with the feed line, between the transmitter and antenna to monitor the standing wave ratio of the station antenna system. Terminal node controller is connected between a transceiver and computer in a packet radio station. A filter must be installed between the transmitter and the antenna to reduce harmonic emissions from your station. A ferrite choke will cure distorted audio caused by RF current flowing on the shield of a microphone cable.

 

Flat strap conductor is best to use for RF grounding. The negative return connection of a mobile transceiver’s power cable is connected at the battery or engine block ground strap. The alternator is the source of a high-pitched whine that varies with engine speed in a mobile transceiver’s receives audio. A variable high-pitched whine on the audio from your mobile transmitter is noise on the vehicle’s electrical system that is being transmitted along with your speech audio.

 

The difference between the repeater’s transmit and receive frequencies describes the common meaning of the term “repeater offset”. Storing the frequency in a memory channel is a way to enable quick access to a favorite frequency on your transceiver. The term “RIT” means Receiver Incremental Tuning. The receiver RIT or clarifier is used if the voice pitch of a single-sideband signal seems too high or low. Microphone connectors on amateur transceivers include push-to-talk and voltages for powering the microphone. Advantage of having multiple receive bandwidth choices on a multimode transceiver is it permits noise or interference reduction by selecting a bandwidth matching the mode. 500 Hz is an appropriate receive filter bandwidth to select in order to minimize noise and interference for CW reception. 2400 Hz is an appropriate receive filter bandwidth to select in order to minimize noise and interference for SSB reception.

 

The keypad or VFO knob can be used to enter the operating frequency on a modern transceiver. The squelch control on a transceiver is used to mute receiver output noise when no signal is being received. If a transmitter is operated with the microphone gain set too high the output signal might become distorted. To keep received audio relatively constant is the function of automatic gain control or AGC. Turning on the noise blanker will reduce ignition interference to a receiver.

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SUBELEMENT T4

Amateur radio practices and station set-up

[2 Exam Questions – 2 Groups]

 

What must be considered to determine the minimum current capacity needed for a transceiver’s power supply?

Power supply regulation and heat dissipation, receiver and control circuit power and efficiency of the transmitter at full power output must be considered to determine the minimum current capacity needed for a transceiver’s power supply.

A computer be used as part of an amateur radio station for logging contacts and contact information, for sending and/or receiving CW and for generating and decoding digital signals.

Wiring between the power source and radio should be heavy-gauge wire and kept as short as possible to avoid voltage falling below that needed for proper operation.

Which computer sound card port is connected to a transceiver’s headphone or speaker output for operating digital modes?

  1. Microphone or line input

What is the proper location for an external SWR meter?

  1. In series with the feed line, between the transmitter and antenna

Which of the following connections might be used between a voice transceiver and a computer for digital operation?

  1. Receive audio, transmit audio, and push-to-talk (PTT)

How is a computer’s sound card used when conducting digital communications?

  1. The sound card provides audio to the radio’s microphone input and converts received audio to digital form

Which of the following conductors provides the lowest impedance to RF signals?

  1. Flat strap

Which of the following could you use to cure distorted audio caused by RF current on the shield of a microphone cable?

  1. Ferrite choke

What is the source of a high-pitched whine that varies with engine speed in a mobile transceiver’s receive audio?

  1. The alternator

Where should the negative return connection of a mobile transceiver’s power cable be connected?

  1. At the battery or engine block ground strap

What may happen if a transmitter is operated with the microphone gain set too high?

  1. The output signal might become distorted

Which of the following can be used to enter the operating frequency on a modern transceiver?

  1. The keypad or VFO knob

What is the purpose of the squelch control on a transceiver?

  1. To mute receiver output noise when no signal is being received

What is a way to enable quick access to a favorite frequency on your transceiver?

  1. Store the frequency in a memory channel

Which of the following would reduce ignition interference to a receiver?

  1. Turn on the noise blanker

Which of the following controls could be used if the voice pitch of a single-sideband signal seems too high or low?

  1. The receiver RIT or clarifier

What does the term “RIT” mean?

  1. Receiver Incremental Tuning

What is the advantage of having multiple receive bandwidth choices on a multimode transceiver?

  1. Permits noise or interference reduction by selecting a bandwidth matching the mode

Which of the following is an appropriate receive filter bandwidth for minimizing noise and interference for SSB reception?

  1. 2400 Hz

Which of the following is an appropriate receive filter bandwidth for minimizing noise and interference for CW reception?

  1. 500 Hz

What is the common meaning of the term “repeater offset”?

  1. The difference between the repeater’s transmit and receive frequencies

What is the function of automatic gain control, or AGC?

  1. To keep received audio relatively constant

Which of the following could be used to remove power line noise or ignition noise?

  1. Noise blanker

Which of the following is a use for the scanning function of an FM transceiver?

  1. To scan through a range of frequencies to check for activity

 

 

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