B-005
Subelement B-005
Section B-005-008
Section B-005-008
A two-times increase in power results in a change of how many dB?
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Correct Answer3 dB higher
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6 dB higher
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1 dB higher
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12 dB higher
GAINS in power: +3 dB = twice, +6 dB = four times (22), +9 dB = eight times (222), +10 dB = ten times, +20 dB = one hundred times (1010), +30 dB = one thousand times (101010). LOSSES: -3 dB = half, -6 dB = one quarter (0.5 * 0.5), -9 dB = one eighth (0.5 * 0.5 * 0.5), -10 dB = one tenth, -20 dB = one hundredth (0.1 * 0.1), -30 dB = one thousandth (0.1 * 0.1 * 0.1).
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
What change in transmitter power results in a 3 dB decrease?
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Divide the original power by 4
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Divide the original power by 3
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Correct AnswerDivide the original power by 2
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Divide the original power by 1.5
GAINS in power: +3 dB = twice, +6 dB = four times (22), +9 dB = eight times (222), +10 dB = ten times, +20 dB = one hundred times (1010), +30 dB = one thousand times (101010). LOSSES: -3 dB = half, -6 dB = one quarter (0.5 * 0.5), -9 dB = one eighth (0.5 * 0.5 * 0.5), -10 dB = one tenth, -20 dB = one hundredth (0.1 * 0.1), -30 dB = one thousandth (0.1 * 0.1 * 0.1).
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
What change in transmitter power results in a 6 dB increase?
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Correct AnswerMultiply the original power by 4
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Multiply the original power by 2
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Multiply the original power by 3
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Multiply the original power by 1.5
GAINS in power: +3 dB = twice, +6 dB = four times (22), +9 dB = eight times (222), +10 dB = ten times, +20 dB = one hundred times (1010), +30 dB = one thousand times (101010). LOSSES: -3 dB = half, -6 dB = one quarter (0.5 * 0.5), -9 dB = one eighth (0.5 * 0.5 * 0.5), -10 dB = one tenth, -20 dB = one hundredth (0.1 * 0.1), -30 dB = one thousandth (0.1 * 0.1 * 0.1).
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 signal transmitted with a power of 200 watts is received with an S-meter reading of "10 dB over S9," what would be the new reading if power was reduced to 20 watts?
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S9 plus 3 dB
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S9 plus 5 dB
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Correct AnswerS9
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S9 minus 10 dB
A reduction at the transmitting station from 200 watts to 20 watts is a drop of -10 dB (one tenth). The received signal strength which reads '10 dB OVER Nine S units' will drop -10 dB to simply 'Nine S units'.
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 signal transmitted with a power of 150 watts is received with an S-meter reading of "20 dB over S9," what would be the new reading if power was reduced to 15 watts?
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Correct AnswerS9 plus 10 dB
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S9 plus 3 dB
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S9 plus 5 dB
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S9
A reduction at the transmitting station from 150 watts to 15 watts is a drop of -10 dB (one tenth). The received signal strength which reads '20 dB OVER Nine S units' will drop -10 dB to simply '10 dB over Nine S units'.
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 "decibel" used for?
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To describe a waveform on an oscilloscope
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Correct AnswerTo measure the ratio of two signals
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To measure a single side band signal
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To describe very high frequency radio waves
The DECIBEL: "A unit used in the COMPARISON of two power levels relating to electrical signals". GAINS in power: +3 dB = twice, +6 dB = four times (22), +9 dB = eight times (222), +10 dB = ten times, +20 dB = one hundred times (1010), +30 dB = one thousand times (101010). LOSSES: -3 dB = half, -6 dB = one quarter (0.5 * 0.5), -9 dB = one eighth (0.5 * 0.5 * 0.5), -10 dB = one tenth, -20 dB = one hundredth (0.1 * 0.1), -30 dB = one thousandth (0.1 * 0.1 * 0.1).
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
The power output from a transmitter increases from 1 watt to 2 watts. How many decibels does that increase represent?
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6 dB
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Correct Answer3 dB
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10 dB
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1 dB
GAINS in power: +3 dB = twice, +6 dB = four times (22), +9 dB = eight times (222), +10 dB = ten times, +20 dB = one hundred times (1010), +30 dB = one thousand times (101010). LOSSES: -3 dB = half, -6 dB = one quarter (0.5 * 0.5), -9 dB = one eighth (0.5 * 0.5 * 0.5), -10 dB = one tenth, -20 dB = one hundredth (0.1 * 0.1), -30 dB = one thousandth (0.1 * 0.1 * 0.1).
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
The power of a transmitter is increased from 5 watts to 50 watts by a linear amplifier. The power gain, expressed in dB, is:
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20 dB
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30 dB
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Correct Answer10 dB
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45 dB
GAINS in power: +3 dB = twice, +6 dB = four times (22), +9 dB = eight times (222), +10 dB = ten times, +20 dB = one hundred times (1010), +30 dB = one thousand times (101010). LOSSES: -3 dB = half, -6 dB = one quarter (0.5 * 0.5), -9 dB = one eighth (0.5 * 0.5 * 0.5), -10 dB = one tenth, -20 dB = one hundredth (0.1 * 0.1), -30 dB = one thousandth (0.1 * 0.1 * 0.1).
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
You add a 9 dB gain amplifier to your 2-watt hand-held. What is the power output of the combination?
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Correct Answer16 watts
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20 watts
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11 watts
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18 watts
GAINS in power: +3 dB = twice, +6 dB = four times (22), +9 dB = eight times (222), +10 dB = ten times, +20 dB = one hundred times (1010), +30 dB = one thousand times (101010). LOSSES: -3 dB = half, -6 dB = one quarter (0.5 * 0.5), -9 dB = one eighth (0.5 * 0.5 * 0.5), -10 dB = one tenth, -20 dB = one hundredth (0.1 * 0.1), -30 dB = one thousandth (0.1 * 0.1 * 0.1).
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
The power of your transmitter is 100 watts and your transmission line introduces a loss of 6 dB. How much power is delivered to the antenna?
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33 watts
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50 watts
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Correct Answer25 watts
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17 watts
GAINS in power: +3 dB = twice, +6 dB = four times (22), +9 dB = eight times (222), +10 dB = ten times, +20 dB = one hundred times (1010), +30 dB = one thousand times (101010). LOSSES: -3 dB = half, -6 dB = one quarter (0.5 * 0.5), -9 dB = one eighth (0.5 * 0.5 * 0.5), -10 dB = one tenth, -20 dB = one hundredth (0.1 * 0.1), -30 dB = one thousandth (0.1 * 0.1 * 0.1).
Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.
Tags: none
A local amateur radio operator reports receiving your 100-watt 2-metre simplex transmission with an S-meter reading of "30 dB over S9." What power could you use to reduce that reading to S9?
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10 W
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Correct Answer0.1 W
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1 W
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33.3 W
To bring a received signal strength of '30 dB OVER Nine S units' down to 'Nine S units' supposes a drop of -30 dB, i.e., one thousandth of the original power. In this example, 100 watts would need to be brought down to 0.1 watts.
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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