Service Technician
A two-way splitter that is 600 feet away from an amplifier has what outputs when given the following: (1) the output of the amplifier is 25 dBmV at 50 MHz and 31 dBmV at 550 Mhz; (2) the 600 feet of cable loses 1.98 dB at 50 MHz and loses 6.48 dB at 550 MHhz; and (3) the two way splitter loses 3.8 dB at 50 MHz and loses 4.4 dB at 550 MHz?
19.22 dBmV at 50 MHz and 20.12 dBmV at 550 MHz.
To transmit AC power efficiently, what power line voltage-current combination would deliver the same amount of power as 10 amps and 10,000 volts, but with the least heat loss?
2 amps and 50,000 volts.
What is the total capacitive reactance of a circuit with two capacitors in series when: (1) the capacitors have individual capacitive reactances of 0.8 ohms and 1.6 ohms; (2) the AC power source is 1 MHz; and (3) the AC power source is 60 volts?
2.40 ohms.
Which testing device is the best to use to measure cable faults?
A time domain reflectometer (TDR).
A hardline RF splitter's
AC characteristics determine the maximum amount of current the splitter can pass and how much hum is introduced to the RF signal.
All true AC waveforms
Always are symmetrical about the horizontal axis.
Which of the following devices is an active device?
An addressable tap.
What is the function of an interdiction unit?
An interdiction unit controls the level of service to the drop ports it contains.
Inductors
Are rated in units of henrys.
Skin-effect losses
Are reduced by using multiple-strand conductors instead of a single, large diameter conductor.
Hardline three-way RF splitters
Are unbalanced when they have two 'low-level' output ports with more signal loss and the one 'high-level' output port with less signal loss.
A fluctuating DC waveform
Can be identical to an AC waveform, except that the fluctuating DC waveform never changes polarity.
The total capacitance of individual capacitors
Connected in series is always smaller than the smallest capacitor value.
Air-core transformers
Get their name from the material used as the core of the transformer.
When compared to unjacketed cable, jacketed hardline coaxial cable
Has additional corrosion protection, more cable support, and improved handling characteristics.
To connect two line passive or active devices together without jumper cables, use a(an)
Housing-to-housing adapter.
Flooding compound should be cleaned from the cable
Immediately after removing the jacket and/or armoring.
As frequency increases through a splitter,
Insertion loss increases.
When the primary-to-secondary turns ratio in a transformer
Is 1:2 or 1/2, the secondary coil voltage is two times larger than the primary coil voltage.
Average Value Method
Is 3.18 volts for a waveform with a peak value of 5 volts.
A farad
Is a unit of capacitance.
The peak value of a waveform
Is another name for the amplitude of the waveform.
The output voltage waveform generated by an AC generator during one complete rotation of the generator's armature
Is called a sine wave.
A transformer
Is either an air-core or an iron-core transformer.
Which statement about the total inductive reactance of a circuit with two inductors in parallel is true?
It is always smaller than the lowest individual inductive reactance value among the inductors in the circuit.
Which of the following is true about the bandwidth of a resonant circuit?
It is the band of frequencies between the 70.7% points of the voltage curve for parallel resonant circuits or the current curve for series resonant circuits.
Which of the following is true about the resonant frequency?
It is the frequency at which the inductive reactance equals the capacitive reactance in a circuit with an inductor and a capacitor.
Which of the following is true about capacitive reactance?
It is the opposition to current flow in an AC circuit caused by a capacitor.
Which of the following describes a A low-pass filter
It is used when upper frequencies are not required in a circuit.
The standard impedance in trunk and feeder coaxial cable
Must be maintained to prevent picture distortions, such as ghosting and smearing.
After wrench-tightening a two-piece pin connector's front nut to an amplifier, two adjustable wrenches are required because
One wrench keeps the front nut from rotating while the other wrench tightens the back nut against the front nut.
A henry is
Quite a large amount of inductance, so inductance in AC circuits is usually expressed as a smaller value; in fractions of one henry.
Attenuation in trunk and feeder coaxial cable
Reduces the amplitude of transmitted signals.
The impedance of coaxial cable or a device is made up of the combined effects of which three electrical properties?
Resistance, inductance, and capacitance.
To properly prepare hardline coaxial cable for connectorization
Some combination coring/stripping tools have an optional stop that automatically sets the coring/stripping depth for the proper center conductor length.
What is the primary difference between coaxial express cable and coaxial distribution cable in an HFC architecture?
Taps are installed on coaxial distribution cable and not on express cable.
Capacitors
That are fully charged act like an open circuit to the source.
Alternating current is a current
That changes direction (or alternates) in the conductor each time the potential difference applied to the ends of the conductor changes (or alternates) its polarity.
In resistive AC circuits,
The AC power waveform has two positive half-cycles and two positive peaks.
When all other factors are equal, if the bonding wire and the cable connecting the drop cable to consumer electronics are the same size, which should be shorter in order to correctly bond the installation?
The bonding wire.
What happens when a capacitor is fully charged?
The current reverses directions and flows back through the source.
Which of the following statements is true?
The dielectric supports the center conductor inside the aluminum sheath while providing an insulating material between the two conductors.
The return loss in trunk and feeder coaxial cable is
The difference in dB between the signal power applied to a terminated cable and the reflected signal power.
Unless specified otherwise, I = E/R for an AC circuit is assumed to mean
The effective value of the current equals the effective value of the voltage divided by the resistance.
Which of the following statements about instantaneous values is true?
The instantaneous value is the value of a single point on the AC waveform at a specific moment, or instant, of time.
The amplitude of a waveform is defined as
The maximum level of either half-cycle of the waveform.
What happens when a source of DC voltage is applied to the plates of a capacitor?
The plate connected to the positive terminal of the source receives a positive charge.
Inductance is
The property of an electrical circuit or conductor that tends to resist changes in the current flowing through the circuit or conductor.
Mutual inductance is
The property possessed by two inductors positioned so that the changing magnetic field lines around one of the inductors encircle, or link, the turns of the other inductor and induce an emf, or voltage, in that inductor.
The capacitance of a capacitor is
The ratio of the electric charge transferred from one plate to the other, to the potential difference between the plates caused by the applied voltage.
Which of the following statements is true?
The velocity of propagation is the rate that RF signals travel through the coaxial cable versus the speed that RF signals travel in free space.
Why would a three-way unbalanced splitter be used in a system design?
There is a need for one of the three output ports to have a lower insertion loss than the other two ports.
How is an AC resistive circuit the same as a DC resistive circuit?
They have similar Ohm's law and power relationships, with certain exceptions.
How many gaskets do hardline two-way RF splitters have?
They have two gaskets, an RFI gasket and an environmental gasket.
To connect a coaxial cable to a 750 MHz amplifier, use a
Three-piece or two-piece pin connector.
A simple AC generator containing a wire loop rotating between the poles of a magnet produces AC voltage
Through magnetism and mechanical motion.
Capacitor charging
Time is directly related to the size of the circuit resistance and the capacitance of the capacitor.
Combination coring/stripping tools are used
To core the dielectric while simultaneously stripping and beveling the aluminum sheath.
When preparing armored cable for connectorization, a tubing cutter is used
To cut all the way through the outer jacket and steel armoring so they can be removed using a knife and pliers.
In abnormal coaxial cable attenuation changes,
Trunk and feeder cable can also possess imperfections that cause random differences in attenuation at different frequencies.
The polyethylene jacket on non-armored coaxial cable should be removed
Using the correct jacket stripping tool for the type and size of cable or a knife.
Which of the following are referred to as trimmer capacitors?
Variable mica capacitors.
Which of the following is the distance occupied by 1 hertz (Hz)?
Wavelength.
Which of the following is used to define the waveform of an optical signal?
Wavelength.
Which of the following statements is true?
When the capacitor plates have no charges on them, no electric field exists between the plates.
What is the interfering RF signal level on output port 2 when: (1) the input leg is terminated; (2) the internal isolation is 32 dB; and (3) there is an applied signal of 7 dBmV on output port 2?
-25 dBmV
What is the time period of one cycle or wavelength of an AC waveform when the frequency of the waveform is 50 Hz?
0.0200 seconds.
What is the power consumed by the load when: (1) the voltage across the load is 7.5 volts; (2) the current flowing through the circuit is 0.25 amperes; and (3) the resistance of the load is 30 ohms?
1.88 watts.
What is the value of the current when: (1) the effective voltage is 120 volts; (2) the resistance of the source is 3 ohms; (3) the resistance of the conductors is 2 ohms; and (4) the resistance of the load is 5 ohms?
12.00 amperes.
What is the total inductive reactance of a circuit with three inductors in series when: (1) the inductors have individual inductances of 15 mh, 20 mh, and 25 mh; and (2) the AC power source is 50 Hz?
18.84 ohms.
What is the two-way splitter's output port signal level @ 50 MHz and 550 MHz when: (1) the amplifier output signal level is 33 dBmV at 550 MHz and 27 dBmV at 50 MHz; (2) there is 500 feet of 0.750 trunk cable between the amplifier and two-way splitter with 0.37 dB loss/100 feet at 50 MHz and 1.24 dB loss/100 feet at 550 MHz; and (3) the splitter's insertion loss is 3.70 dB at 50 MHz and 4.35 dB at 550 MHz?
21.45 dBmV at 50 MHz and 22.45 dBmV at 550 MHz.
What is the total cable loss of a 1,600-foot length of 0.750 cable at 600 MHz and 120 degree F, if at 68 degree F and 600 MHz the cable attenuation rate is 1.31 dB/100 feet? (Be sure to factor in the higher temperature.)
22.05 dB.
What is the power consumed by coaxial cable loop resistance when: (1) the current of the coaxial cable circuit is 5 amperes; (2) the loop resistance of the coaxial cable is .9345 ohms; and (3) the AC power source has an effective voltage of 60 volts?
23.36 watts.
What is the three-way splitter's port signal power level on the high output port when: (1) the input signal level is 27.50 dBmV at 50 MHz and 29.75 dBmV at 550 MHz; (2) the splitter insertion loss through output port A is 6.90 dB at 50 MHz and 7.75 dB at 550 MHz; (3) the splitter insertion loss through output port B is 6.90 dB at 50 MHz and 7.75 dB at 550 MHz; and (4) the splitter insertion loss through output port C is 3.65 dB at 50 MHz and 4.45 dB at 550 MHz?
23.85 dBmV at 50 MHz and 25.30 dBmV at 550 MHz.
What is the wavelength of one cycle of an AC waveform when: (1) the frequency of the waveform is 80 Hz; (2) the speed of light is 300,000 kilometers per second; and (3) the waveform has an amplitude of 5 volts?
3,750 km.
What is the output port signal power level in dBmV at 50 MHz on the high output port of a three-way unbalanced splitter when: (1) the input signal level is 39 dBmV at 50 MHz and 46 dBmV at 750 MHz; and (2) the high output port insertion loss is 4.1 dB at 50 MHz and 5.2 dB at 750 MHz?
34.9 dBmV.
What is the return signal pass band frequency used in most of North America?
5-42 MHz.
What is the average value of an AC waveform that has an effective value of 8 volts?
7.2 volts.
What is the peak-to-peak value of an AC waveform when: (1) the frequency is 60 Hz; (2) the maximum negative value of the waveform is -4 volts; and (3) the effective value of the waveform is 2.83 volts?
8.0 volts peak-to-peak.
Eddy currents
Can cause a loss of power in an AC circuit.
In a power transmission circuit, the transformer located near the user's home, typically
Converts the high voltage, low current combination carried on the transmission lines to a low voltage, high current combination for residential use.
Inductance in an inductor
Decreases when the number of turns around the core are decreased or when there is an increase in the spacing between the turns around the core.
The eddy-current losses in the conductors of an AC circuit are
Dependent on the frequency of the current flowing through the conductors.
The polarity of a DC waveform
Does not change.
Which of the following generally has the highest fixed capacitance values?
Electrolytic capacitors.
Which is inductive reactance?
Equal to 2πƒL; π (pi) is 3.14, f is the frequency of the applied AC source voltage in hertz, and L is the circuit inductance in henrys.
One time constant (t)
Equals the time required to charge a capacitor to 63% of its fully charged voltage.
The amount of power lost as a result of conversion to heat in power transmission lines
Is directly proportional to the amount of resistance present and to the square of the amount of current.
One cycle
Is equal to one complete rotation of the armature of an AC generator.
The total inductance of an AC circuit
Is equal to the sum of all the individual inductances when the circuit's inductors are connected in series.
A phase angle
Is the amount of time, in degrees, it takes the waveform to change from the zero-degree reference point to any other point on the waveform.
Induction
Is the production of an electromotive force (emf) in a conductor by changes in the magnetic field around the conductor.
The trunk and feeder coaxial cable's DC loop resistance
Is the sum of the center conductor resistance and the aluminum sheath resistance.
The center conductor of trunk and feeder coaxial cable
Is typically bonded to the dielectric with a polymer adhesive coating or center conductor treatment to inhibit moisture migration and corrosion.
Which of the following describes counter electromotive force (cemf)?
It determines the amount of current flowing through the circuit from the AC source, in an inductive AC circuit.
The hardline RF splitter mechanical component that
Makes a mechanical and an electrical connection between the splitter and the coaxial cable's pin connector is the seizure screw.
The basic power relationship "p(t) = e(t)i(t)"
Means the power at a specific instant equals the voltage at that same instant times the current at that instant.
After a foam dielectric cable is properly cored and stripped, the cable's center conductor should be
Prepared with a pyramid-shaped cut to the tip.
The square wave and the sawtooth wave AC waveforms
Seem to decrease "instantly" from a maximum positive value to a maximum negative value of voltage or current.
To weatherproof a pin connector with heat shrink, the tubing
Should be cut straight and clean if it needs to be trimmed, because jagged edges might split the tubing when it is heated.
