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2016 Master > numbers tech related > Flashcards

Flashcards in numbers tech related Deck (93):
1

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

3 dB

2

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

20 microvolts per meter at 3 meters

3

What is the typical bandwidth for C-band service?

500 MHz

4

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

950 MHz - 1450 MHz

5

All drop splitters must have a minimum return bandwidth of?

5 MHz to 42 MHz

6

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

250 microns

7

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

52.42

8

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

87.5

9

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

150 feet

10

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

600 mA

11

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

6 feet

12

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

Internal 75-ohm resistor

13

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

20 microvolts per meter at 3 meters

14

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

68 degrees Fahrenheit (293.15 degrees Kelvin)

15

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

30 inches

16

What is the minimum cable bend radius for series 6?

2.5 inch radius

17

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

<64

18

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

2 dBmV

19

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

36 MHz

20

What is 1 per million as expressed in scientific notation?

1.0E-6

21

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

0 dBmV

22

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

0.25(+/-.1dB)

23

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

6

24

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

1.544 Mbps

25

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

1 ohm

26

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

15 microvolts/meter at 30 meters (100 feet)

27

What frequency does Comcast use for the MoCA channel?

1,150 MHz or 1.15 GHz

28

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

180 Mbps

29

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

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

30

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

20 inch lbs.

31

What is the value for Boltzmann's Constant?

1.38x10E-23

32

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

2

33

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

#10BRIS 7.1.7

34

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

2

35

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

Within 2 dB of each other

36

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

-20VDC

37

Which log value is used to calculate carrier to noise?

10

38

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

59.2 dB (+/- .5dB)

39

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

8,000 per second

40

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

54 MHz to 1,002 MHz (1GHz)

41

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

#6 AWG to #14 AWG solid copper

42

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

14 inches (or the same height as existing outlets)

43

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

10

44

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?

5 feet

45

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

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

46

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

Between 24 and 28 VDC

47

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

0.3 VDC

48

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

9

49

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

Up to 3

50

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

20-149 uV/M

51

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

0.25 (+/-.1dB)

52

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

0 dBmV

53

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

3

54

Which pad value is typically used in return amplifiers?

0

55

A PRI trunk employs of how many D channels?

1

56

What are the 2 output wavelengths of lasers?

1310mm and 1550mm

57

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

1310nm and 1550nm

58

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

1, 2, 4 and 5

59

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

6

60

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

1000 feet

61

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

8.1 dB

62

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

1/16" to 1/8"

63

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

90% of the maximum modulator output

64

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

40 MHz

65

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

3 times

66

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

18 inches

67

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

9 dBmV

68

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

2 amperes

69

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

46

70

What is the typical loss through a fusion splice?

0.1 dB

71

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

21.6 inches

72

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

35 dB

73

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

2 to 4 inches / 5-10 cm

74

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

12 inches

75

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

5 percent

76

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

250', 2

77

Return amplifiers have this much gain?

20 dB

78

What are the Aeronautical Frequency Bands?

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

79

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

1500ft and 108 to 137 MHz

80

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

1dB

81

What are the Node DC Power pack voltages?

24 volts, 12 volts, and 5 volts

82

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

0.5 dB

83

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

30 dB

84

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

57 dB

85

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

60 dB

86

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

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

87

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

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

88

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

50 KHz, 25 KHz; +/-5KHz

89

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

30 ft to 50 ft

90

Stop the lash about _____ feet from the pole?

6 ft

91

What is the voltage for power over Ethernet?

48 VDC

92

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

30.72 Mbps

93

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

42.88 Mbps

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