Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

AZ ENP Study Session > 2 9-1-1 Operations > Flashcards

2 9-1-1 Operations Flashcards

1
Q

What is LMR

A

Land Mobile Radio

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the FCC

A

Federal Communications Commission

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Radio Waves

A

electromagnetic waves that travel through the atmosphere

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What determines distance radio waves travel?

A

Frequency/wavelength

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What happens when a wave travels through the atmosphere?

A

It loses strength

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Result of migration to higher frequencies?

A

Limited range of radio signals/required use of Repeaters to ensure coverage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Band

A

Small section of the spectrum of radio frequencies in which channels are assigned by the FCC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Radio Channels

A

Pairs of frequencies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Radio Spectrum

A

Limited resource, FCC mandated “narrowbanding” to create more spectrum availability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Narrowbanding

A

changing the width of frequency from 25 KHz to 12.5 KHz

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

VLF

A

Very Low Frequency 10 to 30 KHz

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

LF

A

Low Frequency 30 to 300 kHz

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

MF

A

Medium Frequency 300 to 3000 kHz

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

HF

A

High Frequency 3 to 30 MHz

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

VHF

A

very-high frequency 30 to 300 MHz

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

UHF

A

Ultra High Frequency 300 to 3000 MHz

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

SHF

A

Super-high frequency 3 to 30 GHz

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

EHF

A

Extremely High frequency 30 to 300 GHZ

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Radio signals in this frequency range tend to travel greater distances than those of higher frequency. Work well as inter-city communications

A

VHF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

VHF for Public Safety

A

150 to 170 MHz bands. Preferred by rural agencies as they provide better coverage in uneven terrain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Frequencies include 400 MHz, 500 MHz, 700 MHz, 800 MHz and 900 MHz

A

UHF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Radio signals in this band do not travel as far as lower frequencies, but penetrate structures better

A

UHF

23
Q

2 operational bands in public safety for LMR in N. America

A

UHF: UHF1 (400 MHz) UHF2 (500 MHz) and UHF “T Band” and 2nd is 7/800 MHz

24
Q

may be limited to a subset of bands

A

Older Radio Equipment

25
Q

Multiband Radio models

A

Support large number of bands including VHF, UHF and 7-800 MHz in a single radio.

26
Q

Trunked Radio

A

All users share same radio frequencies, all depts can access all of the channels - talk groups are assigned

27
Q

Reasons Trunked Radio Systems are efficient use of spectrum

A
  1. Most conversations are short 2. not all users need to access the system at the same time.
28
Q

Channel use is dedicated

A

Conventional radio system

29
Q

How trunked channels work

A

Pairs of channels are used and each channel has two frequencies; one transmits inbound frequencies to a repeater and the other transmits outbound frequencies.

30
Q

Trunked mobile and portable radios

A

act like remote online computers and are in continual contact with their associated base stations

31
Q

Control Channel

A

one channel in a system that mobile and base radios use to exchange information - not controlled by the radio operator.

32
Q

Request to Talk

A

signal sent to the base station when an operator presses the transmit button. The system authenticates the radio’s ID against the database and responds with a channel assignment for the transmission. the control channel then sends a message to all members of the talk group to tune their receivers to the assigned frequency. The mobiles then automatically change to the assigned channel. Occurs in milliseconds.

33
Q

Sharing Channels (Trunking)

A

Allows more users on fewer channels than a conventional radio system

34
Q

How many users can a 10-channel trunked radio system support

A

800 users (and one channel is operating as the control channel)

35
Q

Main Difference between conventional and trunked radio

A

On a conventional system the channel switching is manually controlled by the user, in a trunked radio system the channel switching is controlled by the software.

36
Q

Mobile vs Portable Radio’s (main difference)

A

Mobile radios transmit signals at a higher power than portables

37
Q

Portable radio transmit power

A

Generally limited to 5 watts

38
Q

Mobile radio transmit power

A

may go as high as 100 Watts

39
Q

Output power of radios in the field

A

based on the system design and type

40
Q

Factor allowing Mobile radios to transmit and receive signals better and farther than portable radios

A

Antenna!

41
Q

Why is it important how a users speaks into a portable radio?

A

if a user holds the radio to their mouth to speak the radio is about 5-6 feet off the ground and mostly unobstructed. If they use a portable mic and the radio stays attached to their belt, it is only about 3 feet off the ground and potentially obstructed by the users body.

42
Q

Old “rule of thumb” for radio power

A

100 watts at 100 feet equals 100 miles

43
Q

Radio power today

A

Limitation on how far a radio signal can and should travel. Primarily to allow many users to share the same channels but be a certain distance from each other.

44
Q

Simplex System

A

basic radio system that transmits and receives on the same frequency. Does not require base equipment but can be used with base stations.

45
Q

Walkie-Talkie Radio Mode

A

Often referred to as “direct” mode, where two radios are talking directly to each other when they are close in proximity but the repeater is not nearby.

46
Q

Repeater Systems

A

A method of increasing the coverage area of a radio system. A series of repeaters and satellite receivers are set up allowing mobile and portable users to communicate at greater distances.

47
Q

How does a Repeater work?

A

radio transmits on one frequency while the base transmitter retransmits the signal on another frequency. The radios receive the transmitters repeat of the transmission.

48
Q

Talk- Around

A

When a mobile or portable is programmed with a simplex channel that uses the base station’s transmit frequency. Allows the user to communicate with others without using the repeater, but can still hear the repeater and respond when needed. Talk around only works with radios in a very limited area.

49
Q

Satellite/voting Receiver Systems

A

For increased signal reception, take signal from portable or mobile and send signals via microwave or landline to a central controller. The central controller then selects (votes) the best audio signal and passes signal back to the radio system

50
Q

Simulcast Systems

A

Transmits message over more than one transmitter on the same frequency. Allows for very robust and widespread systems.

51
Q

Analog Signaling

A

uses the voice’s vibration to send the voice to the transmitter.

52
Q

Digital Signaling

A

voice is converted to a digital signal using a voice coder or “vocoder” This device will sample the voice and convert it to digital 1s and 0s which are transmitted. This is transmitted to the receiver where it is converted back to analog (audible) sound capable of being heard and understood by the listener.

53
Q

Data Signaling

A

Integral component of trunked P25 systems. Both radio audio and data are treated the same - audio is more data. Can be as simple as the radio ID to short messages and even remote control of remote equipment.

AZ ENP Study Session (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions