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2015 Dan > numbers tech related > Flashcards

numbers tech related Flashcards

1
Q

According to the C/N rule, each time the number of amplifiers doubles, the C/N gets worse by how much?

A

3 dB

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2
Q

Per FCC rules, signal leakage between 54 MHz and 216 MHz must not exceed what?

A

20 microvolts per meter at 3 meters

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3
Q

What is the typical bandwidth for C-band service?

A

500 MHz

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4
Q

What frequency range must a spectrum analyzer have in order to align satellite dishes?

A

950 MHz - 1450 MHz

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5
Q

All drop splitters must have a minimum return bandwidth of?

A

5 MHz to 42 MHz

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6
Q

What is the diameter, in microns, of a single mode fiber strand with the coating intact?

A

250 microns

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7
Q

“Four Nines” or 99.99% reliability allows for how many downtime minutes per customer per year? +/- 1 min.

A

52.42

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8
Q

What is the proper depth of modulation percentage of the properly balanced video carrier?

A

87.5

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9
Q

What is the maximum length of a series-6 drop that can be used in an underground installation?

A

150 feet

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10
Q

What is the maximum current output supported by the Vista 20P control panel?

A

600 mA

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11
Q

What is the maximum length for a coax jumper used between a wall plate and the CPE?

A

6 feet

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12
Q

When terminating an unused tap port, what must be included in the terminator?

A

Internal 75-ohm resistor

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13
Q

Per FCC rules, signal leakage between 54 Mhz and 216 Mhz must not exceed what?

A

20 microvolts per meter at 3 meters

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14
Q

What is the reference temperature to determine thermal noise level delivered to any load impedance?

A

68 degrees Fahrenheit (293.15 degrees Kelvin)

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15
Q

When making attachments to the strand, what is the minimum distance from the center of the pole that the attachment can be made?

A

30 inches

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16
Q

What is the minimum cable bend radius for series 6?

A

2.5 inch radius

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17
Q

What CLI figure of merit must be met in order to comply with Federal Communications Commission Standards?

A

equal to or below 64

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18
Q

For each dB increase in input optical power (dBm), the RF output increases by how many dBmV?

A

2 dBmV

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19
Q

How much bandwidth is required when both video and audio broadcasts are sent via a satellite in analog format?

A

36 MHz

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20
Q

What is 1 per million as expressed in scientific notation?

A

1.0E-6

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21
Q

What is 1 millivolt equal to across a 75 ohm load?

A

0 dBmV

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22
Q

What is the typical 1550nm fiber loss in dB/km?

A

0.25(+/-.1dB)

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23
Q

When purchasing a fractional PRI, what is the minimum number of channels required per account?

A

6

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24
Q

What is the total bandwidth, to the nearest thousandth, required for a single 24-channel PRI circuit?

A

1.544 Mbps

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25
Q

What resistance is present in a circuit where 1 ampere of current dissipates 1 watt of power?

A

1 ohm

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26
Q

What is the FCC signal leakage limit for frequencies below 54 MHz and above 216 MHz?

A

15 microvolts/meter at 30 meters (100 feet)

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27
Q

What frequency does Comcast use for the MoCA channel?

A

1,150 MHz or 1.15 GHz

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28
Q

What is the minimum PHY rate required between the Media Hub and the terminal?

A

200 Mbps

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29
Q

When is the use of Series-11 or QR-320 permissible for an aerial drop?

A

Greater than 150 feet or in situations where it will improve signal levels to within acceptable ranges

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30
Q

What is the acceptable minimum tightening force for the connector on the port of a splitter?

A

20 inch lbs.

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31
Q

What is the value for Boltzmann’s Constant?

A

1.38x10E-23

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32
Q

What is the maximum number of lines supported by a Polycom 335?

A

2

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33
Q

What size ground wire is used with series-11 and QR320 cables?

A

10BRIS 7.1.7

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34
Q

How many splices are permitted in an underground drop restoration with a cable longer than 60 feet which does NOT cross a driveway?

A

2

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35
Q

To reduce the possibility of bleeding, carrier power levels of adjacent channels should be kept within what distance of each other?

A

Within 2 dB of each other

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36
Q

In a typical off-hook state, what is the level of tip wire voltage?

A

-20VDC

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37
Q

Which log value is used to calculate carrier to noise?

A

10

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38
Q

If the input level (in dBmV) numerically equals an amplifier’s noise figure, what will the output C/N be?

A

59.2 dB (+/- .5dB)

39
Q

At 64 Kbps, what is the sample rate per second in the G711PCM encoding scheme?

A

8,000 per second

40
Q

What is the forward bandwidth that must be supported by all active and passive equipment?

A

54 MHz to 1,002 MHz (1GHz)

41
Q

Which size bonding wires must be accommodated by the bonding wire attachment?

A

6 AWG to #14 AWG solid copper

42
Q

When installing an outlet, what is the standard height, in inches, from the floor to the bottom of the wall plate?

A

14 inches (or the same height as existing outlets)

43
Q

What is the number designation for a violet colored fiber optic cable?

A

10

44
Q

When bonding to a cold water pipe at the customer premise, what is the maximum distance the bond block can be from where the metal water pipe enters the home?

A

5 feet

45
Q

What is the distance a mechanical bender must remain in position until the lasher is transferred and the next span of cable is lashed?

A

50 feet or 1/3 the distance to the next pole

46
Q

What level of DC voltage would you expect to find at an amplifier DC test point?

A

Between 24 and 28 VDC

47
Q

When testing batteries in a standby power supply, the difference in voltage levels should be no more than how many VDC?

A

0.3 VDC

48
Q

How many test points are required by the FCC for every 45,000 customers?

A

9

49
Q

For high resolution traces, how many sweep points may be entered for each 6MHz segment of bandwidth?

A

Up to 3

50
Q

What is the minimum / maximum level of a leak that must be fixed within 72 hours?

A

20-149 uV/M

51
Q

What is the typical 1550 nm fiber loss in dB/Km?

A

0.25 (+/-.1dB)

52
Q

What is 1 millivolt equal to across a 75 ohm load? (dBmV)

A

0 dBmV

53
Q

What is the maximum number of devices that can be monitored from the Device Monitor tool in Watchtower?

A

3

54
Q

Which pad value is typically used in return amplifiers?

A

0

55
Q

A PRI trunk employs of how many D channels?

A

1

56
Q

What are the 2 output wavelengths of lasers?

A

1310mm and 1550mm

57
Q

What are the 2 most common optical wavelengths used by the CATV industry?

A

1310nm and 1550nm

58
Q

Which numbered pins are being used for transmit and receive when utilizing the RJ48C connection?

A

1, 2, 4 and 5

59
Q

When purchasing a fractional PRI, what is the minimum number of channels required per account?

A

6

60
Q

What is the visibility rating on a clear night for a road barrier’s type B high intensity Warning Light?

A

1000 feet

61
Q

How much does signal attenuate on a 4-way splitter at 750 MHz?

A

8.1 dB

62
Q

How far should the center conductor project form the F-connector’s edge?

A

1/16” to 1/8”

63
Q

What is the recommended modulator output in order to prevent overdriving the final amplifier stage?

A

90% of the maximum modulator output

64
Q

What is the transponder bandwidth that allows for the carriage of additional signals, such as additional audio and data communications?

A

40 MHz

65
Q

How much must a preamplifier increase the signal strength before feeding it to the power amplifier?

A

3 times

66
Q

What would be the maximum allowable sag in a 150’ drop?

A

18 inches

67
Q

What is the output of a tap with an input of 23 dBmV and a value of 14?

A

9 dBmV

68
Q

Given voltage =10 and resistance =5, what would the current be?

A

2 amperes

69
Q

If a customer has 2 PRI, what is the maximum number of simultaneous calls they can have?

A

46

70
Q

What is the typical loss through a fusion splice?

A

0.1 dB

71
Q

What is the screen height of a 16:9 display measuring 42 inches diagonally?

A

21.6 inches

72
Q

What is the acceptable MER measurement on a 256 QAM at the tap?

A

35 dB

73
Q

How many inches does a strain relief loop drop when installing fiber optic cable?

A

2 to 4 inches / 5-10 cm

74
Q

What minimum distance should an aerial lift maintain from a power line that is between 800 volts and 750 volts?

A

12 inches

75
Q

During construction, what percentage of fiber cable is normally dedicated to “excess slack loops?”

A

5 percent

76
Q

If a span is ____ feet or longer, place _____ expansion loops on each pole.

A

250’, 2

77
Q

Return amplifiers have this much gain?

A

20 dB

78
Q

What are the Aeronautical Frequency Bands?

A

108 to 137 MHz (Aeronautical Radio) and225 to 400 MHz (Aeronautical Navigation)

79
Q

At what altitude and frequency range is a flyover done at?

A

1500ft and 108 to 137 MHz

80
Q

What is the insertion loss of a diplex filter at 42Mhz?

A

1dB

81
Q

What are the Node DC Power pack voltages?

A

24 volts, 12 volts, and 5 volts

82
Q

What is a DC-20s insertion loss at 42MHz?

A

0.5 dB

83
Q

You will not see a ghost, whose level is more than _____dB below the desired carrier?

A

30 dB

84
Q

Carrier to beat ratios are greater than _____ are far enough below desired carrier levels to be of little concern to the average viewer?

A

57 dB

85
Q

In order for Co-channel interference to be visible, the difference in levels between the desired and undesired channels must be less than ____dB?

A

60 dB

86
Q

In CSO, the offending location is a group of beats located where?

A

1.25 MHz (+/- 15KHz) above the interfered channel’s visual carrier

87
Q

Aeronautical radio communications bands operating frequencies are spaced at _____intervals, so cable carriers must be offset by _____?

A

25 KHz intervals, 12.5 KHz; +/-5KHz

88
Q

Aeronautical navigation carriers are spaced at ____ between carriers. For this reason, cable signals using this portion of the spectrum must be offset by _____?

A

50 KHz, 25 KHz; +/-5KHz

89
Q

Cable blocks should be placed on the strand every _____ to ______ ft?

A

30 ft to 50 ft

90
Q

Stop the lash about _____ feet from the pole?

A

6 ft

91
Q

What is the voltage for power over Ethernet?

A

48 VDC

92
Q

What is the maximum data throughput for a 64 QAM channel?

A

30.72 Mbps

93
Q

What is the maximum data throughput for a 256 QAM channel?

A

42.88 Mbps

2015 Dan (22 decks)

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