LESSON 15

How radio works: receivers, transmitters, transceivers,
amplifiers, power supplies, types of batteries, service life

The basic amateur radio station consists of a transmitter, a receiver and an antenna. Some times the transmitter and the receiver are combined in a single unit called a transceiver.

The transmitter is the piece of equipment that generates, amplifies, and modulates the outgoing radio signal while the receiver is used to convert the incoming radio signals into sound we can hear, video we can see, or controls we can use.

The transmitter and the receiver can not operate without power. The power source may be battery power but with a base station most of the time the power source is the house hold AC power. Unfortunately raw AC can not be used to run these radios and thus a power supply must be used either internally or externally to convert the AC to the proper level DC power. The voltage output from a power supply will normally be lower then the 120 Volts house power but if vacuums tubes are being used the voltage will be raised to a higher level.

There are many types of batteries available today. The most common rechargeable types are Lead-Acid, Alkaline, Nickel-cadmium, and Lithium-ion. Of the battery types listed the one that offers the longest life when used with a hand-held radio, assuming each battery is the same physical size is the lithium-ion but it is also the most expensive. The voltage per cell of a Nickel-Cadmium battery is 1.2 volts.

The Carbon-zinc, commonly called a dry cell battery, is not designed to be recharged.

To get the most out of a battery and to be sure they are ready in case of an emergency proper care is important. They should be inspected for physical damage and replaced if necessary, stored in a cool dry location, and given a maintenance recharge at least every 6 months.

To get the most energy from a battery the current from the battery should be at the slowest rate needed

1. T4C01
What is used to convert radio signals into sounds we can hear?
A. Transmitter
B. Receiver
C. Microphone
D. Antenna
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2. T4C02
What is used to convert sounds from our voice into radio signals?
A. Transmitter
B. Receiver
C. Speaker
D. Antenna
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3. T4C03
What two devices are combined into one unit in a transceiver?
A. Receiver, transmitter
B. Receiver, transformer
C. Receiver, transistor
D. Transmitter, deceiver
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4. T4C04
What device is used to convert the alternating current from a wall outlet into low-voltage direct current?
A. Inverter
B. Compressor
C. Power Supply
D. Demodulator
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5. T4C05
What device is used to increase the output of a 10 watt radio to 100 watts?
A. Amplifier
B. Power supply
C. Antenna
D. Attenuator
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6. T4C06
Which of the battery types listed below offers the longest life when used with a hand-held radio, assuming each battery is the same physical size?
A. Lead-acid
B. Alkaline
C. Nickel-cadmium
D. Lithium-ion
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7. T4C07
What is the nominal voltage per cell of a fully charged nickelcadmium battery?
A. 1.0 volts
B. 1.2 volts
C. 1.5 volts
D. 2.2 volts
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8. T4C08
What battery type on this list is not designed to be re-charged?
A. Nickel-cadmium
B. Carbon-zinc
C. Lead-acid
D. Lithium-ion
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9. T4C09
What is required to keep rechargeable batteries in good condition and ready for emergencies?
A. They must be inspected for physical damage and replaced if necessary
B. They should be stored in a cool and dry location
C. They must be given a maintenance recharge at least every 6 months
D. All of these answers are correct
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10. T4C10
What is the best way to get the most amount of energy from a battery?
A. Draw current from the battery as rapidly as possible
B. Draw current from the battery at the slowest rate needed
C. Reverse the leads when the battery reaches the 1/2 charge level
D. Charge the battery as frequently as possible
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Answers: B A A C A D B B D B