Download Tech Exam Study Aid - effective July 1, 2010

Frequently Asked Questions for the Amateur Radio Technician Class Exam
What is CW? It stands for Continuous Wave, but for purposes of the exam, it simply
means Morse Code - to explain this completely requires more technical information that
what's intended for the Tech exam, so just think of it as Morse.
To allow communications on CW without interference from voice stations, the FCC rules
state that only CW may be used on the first 0.1MHz of some bands. Here are exam
questions that mention CW:
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What emission modes are permitted in the mode-restricted sub-bands at 50.0 to
50.1 MHz and 144.0 to 144.1 MHz? CW only
Which of the following types of emission has the narrowest bandwidth? CW CW
takes up the least space on your radio dial - voice signals are much wider!
What is the approximate maximum bandwidth required to transmit a CW signal?
150 Hz
Which of the following is an appropriate receive filter to select in order to
minimize noise and interference for CW reception? 500 Hz
How can I remember all those frequencies and wavelengths? There's a relationship
between frequency and wavelength: Wavelength is the distance a radio wave travels as it
makes one cycle of rising positively, passing through zero, going negative and returning
to zero. Since it's travelling at 300,000,000 meters per second ( speed of light), and the
cycles per second (Hertz, abbreviated Hz) are also in the millions (MHz), you can
'cancel' the millions and you have 300 (million meters/sec) and the frequency in MHz.
Divide 300 by the frequency and you get the wavelength. The same relationship holds
when you know the wavelength and want to know the frequency: divide 300 by
wavelength to get frequency.
Was that too much math and science? Well, you can just memorize those frequencies and
wavelengths and still pass the exam. Your choice.
To get frequency, divide 300 by the wavelength (in Meters). To get wavelength, divide
300 by the frequency (in MHz).
So, notice in the following questions and answers (of which you might get just one on the
exam), that the answer is approximately 300 divided by the number in the question.
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Which frequency is within the 6-meter band? 52.525 MHz (50 = 300/6) 6m band
= 50 to 54MHz, so 49MHz isn't in the 6m band.
Norm & Naomi Goodkin's Ham Radio Class  2010
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Frequently Asked Questions for the Amateur Radio Technician Class Exam
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Which amateur band are you using when transmitting on 146.52 MHz?
2 meter band (2 = approximately 300/146.525) 2m band = 144 to 148MHz
Which 70-centimeter frequency is authorized to a Technician class license holder
operating in ITU Region 2? 443.350 MHz (70cm = approximately 300/443.350)
70cm band = 420 to 450MHz, so 455MHz isn't in the 70cm band.
Which 23 centimeter frequency is authorized to a Technician class license holder
operating in ITU Region 2? 1296 MHz (23cm = approximately 300/1296)
What amateur band are you using if you are operating on 223.50 MHz?
1.25 meter band (1.25 = approximately 300/223.50)
And notice that since wavelength = 300/frequency, the wavelength gets shorter as the
frequency increases.
Using the above info, you should also be able to answer these, or at least understand
them:
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What is the name for the distance a radio wave travels during one complete cycle?
Wavelength
What term describes the number of times that an alternating current flows back
and forth per second? Frequency
What does 60 hertz (Hz) mean? 60 cycles per second
Electromagnetic waves that oscillate more than 20,000 times per second as they
travel through space are generally referred to as what? Radio waves
How fast does a radio wave travel through space? At the speed of light
How does the wavelength of a radio wave relate to its frequency?
The wavelength gets shorter as the frequency increases.
What is the formula for converting frequency to wavelength in meters?
Wavelength in meters equals 300 divided by frequency in megahertz.
What are sound waves in the range between 300 and 3000 Hertz called?
Voice frequencies
What property of a radio wave is often used to identify the different bands
amateur radio operators use? The physical length of the wave
What is the frequency range of the 2 meter band in the United States?
144 to 148 MHz (300/144 = approximately 2)
What is the frequency range of the 6 meter band in the United States?
50 to 54 MHz (50 = 300/6)
What is the frequency range of the 70 centimeter band in the United States?
420 to 450 MHz (300/450 = approximately .70m = 70cm)
Is there an easy way to remember the Ohm's Law forumlas? If you understand
physics and algebra, then just remember that the more voltage (E) you have, the more
current (I) you get; conversely, the more resistance you have (R), the less current you get.
So, I = E/R.
You can use this nifty little diagram to remember the formula.
Norm & Naomi Goodkin's Ham Radio Class  2010
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Frequently Asked Questions for the Amateur Radio Technician Class Exam
Think of Lake ERI, start at the top and write the letters E, R, and I. E stands for Voltage,
R stands for Resistance, and I stands for Current:
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E is the Voltage (Electromotive Force), measured in Volts
R is Resistance, measured in Ohms
I is the Intensity of the electrical Current measured in Amperes or Amps
To find the value they ask for (E, R, or I), cover up E, R, or I, and figure out whether to
multiply or divide the other two; multiply if the remaining two are next to each other.
Divide if the remaining two are above and below each other.
If they ask for R, for example, put your finger over R and you're left with E "over" I, so
divide E by I. If the two that are left are next to each other, multiply.
You can write this diagram on the back or margin of your answer sheet (BUT NOT
YOUR TEST BOOKLET!), as soon as you get it, so you don't have to remember it very
long. You can use this diagram to answer the following test questions: (only one will be
on the test):
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What formula is used to calculate current in a circuit?
Current (I) equals voltage (E) divided by resistance (R)
What formula is used to calculate voltage in a circuit?
Voltage (E) equals current (I) multiplied by resistance (R)
What formula is used to calculate resistance in a circuit?
Resistance (R) equals voltage (E) divided by current (I)
What is the resistance of a circuit when a current of 3 amperes flows through a
resistor connected to 90 volts? 30 ohms (R = E/I, so R = 90/3 = 30 ohms)
What is the resistance in a circuit where the applied voltage is 12 volts and the
current flow is 1.5 amperes? 8 ohms (R = E/I, so R = 12/1.5 = 8 ohms)
What is the current flow in a circuit with an applied voltage of 120 volts and a
resistance of 80 ohms? 1.5 amperes (I = E/R, so I = 120/80 = 1.5 amperes)
What is the voltage across the resistor if a current of 0.5 amperes flows through a
2 ohm resistor? 1 volt (E = IR, E = 0.5 x 2 = 1 volt)
What is the voltage across the resistor if a current of 1 ampere flows through a 10
ohm resistor? 10 volts (E = IR, so E = 1 x 10 = 10 volts)
What is the voltage across the resistor if a current of 2 amperes flows through a 10
ohm resistor? 20 volts (E = IR, so E = 2 x 10 = 20 volts)
Norm & Naomi Goodkin's Ham Radio Class  2010
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Frequently Asked Questions for the Amateur Radio Technician Class Exam
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What is the current flowing through a 100 ohm resistor connected across 200
volts? 2 amperes (I = E/R, so I = 200/100 = 2 amperes)
What is the current flowing through a 24 ohm resistor connected across 240 volts?
10 amperes (I = E/R, so I = 240/24 = 10 amperes)
Remember "Easy as PIE" with this diagram.
Did you know that James Watt was very good friends with Marie Callender?
Neither did I, but it might help you remember. Power (Watts) = Current (I) x
Voltage (E), or P = IE
This applies to these questions:
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Electrical Power is measured in which of the following units? Watts
What unit is used to describe electrical power? Watt
What is the formula used to calculate electrical power in a DC circuit?
Power (P) equals voltage (E) multiplied by current (I)
How much power is represented by a voltage of 13.8 volts DC and a current of 10
amperes? 138 watts
How much power is being used in a circuit when the voltage is 120 volts DC and
the current is 2.5 amperes? 300 watts
How can you determine how many watts are being drawn by your transceiver
when you are transmitting? Measure the DC voltage at the transceiver and
multiply by the current drawn when you transmit.
How many amperes are flowing in a circuit when the applied voltage is 120 volts
DC and the load is 1200 watts? 10 amperes
How many milliamperes is the same as 1.5 amperes? 1500 milliamperes
Norm & Naomi Goodkin's Ham Radio Class  2010
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