CB RADIO INFO WEBSITE

 

QUESTIONS AND THEORY OF CITIZEN BAND RADIO

CLICK ON ANY OF THE TOPICS LISTED TO GO TO THAT SECTION

CB RADIO FREQUENCIES
CB Radio "10 Codes"
CB Radio "Q Codes (SSB) "
Citizens Band (CB)
Licensing
Operations 
Equipment 
Territorial Limits
Linear Amplifier Ban
Antennas
How a CB Antenna works
Adjust your SWR on your CB radio
How does an antenna size affect my CB radio?
What is a Citizen Band radio?
What do I need to operate on the Citizen Band?
What do all the dials on the CB do?
I hooked up my CB and can hear people, but they can't hear me?
How long should my antenna be?
How do I tune my SWR, and how do I measure it?
How can I boost the strength of my outgoing signal? Legal and Illegal
options?
Are you assigned a handle or can you make one up? What are the numbers 
for identification I hear people using?
Is it okay to talk to a station that is really far away if the skip 
allows it?
When I'm talking to someone, somebody else starts talking and 
interrupts our conversation. It causes a lot of humming and is really annoying. Can 
they do this?
I notice when I'm up on a hill I can receive and transmit well, but 
when I'm in a valley I can't hear  anyone?
What are no ground antennas?

Citizens Band (CB)

Citizens Band (CB) Radio Service is a private two-way voice communication service for use in personal and business activities of the general public. Its communications range is from one to five miles.

Licensing

License documents are neither needed nor issued and there are no age or citizenship requirements. As long as you use only an unmodified FCC certificated CB unit, you are provided authority to operate a CB unit in places where the FCC regulates radio communications.

Operations

You are provided authority to operate a CB unit in places where the FCC regulates radiocommunications, as long as you use only an unmodified FCC certificated CB unit. An FCC certificated unit has an identifying label placed on it by the manufacturer. Read more about restrictions of operations and usage of channels

Equipment

You must use an FCC certificated CB transmitter at your CB station. You can identify an FCC certificated transmitter by the certification label placed on it by the manufacturer.

Territorial Limits

You may operate your CB unit within the territorial limits of the fifty United States, the District of Columbia, and the Caribbean and Pacific Insular areas ("U.S."). You may also operate your CB on or over any other area of the world, except within the territorial limits of areas where radio-communications are regulated by another agency of the U.S. or within the territorial limits of any foreign government. You may also be permitted to use your CB unit in Canada subject to the rules of Industry Canada. Travelers to the U.S. may operate a CB unit within the U.S. as long the unit is FCC certificated.

Linear Amplifier Ban

Users may not raise the power output of their CB units. That would be unfair to the other users sharing the channel by raising the level of radio noise. You must not attach a "linear," "linear amplifier" or any other type of power amplifier to your CB unit, Moreover, you must not modify your CB unit internally. Doing so cancels its certification and you forfeit your authorization to use it.

Antennas

There are no height restrictions for antennas mounted on vehicles or for hand-held units. For structures, the highest point of your antenna must not be more than 20 feet above the highest point of the building or tree on which it is mounted, or 60 feet above the ground. There are lower height limits if your antenna structure is located within two miles of an airport.

Ten Codes

Ten-codes are operating aids used by public safety and other professional communicators. The FCC does not regulate the meaning of the ten-codes. You may use an on-the-air pseudonym ("handle") of your choosing.

Channels

There are 40 shared CB channels used on a "take-turns" basis. There are no channels authorized in the CB Radio Service above 27.405 MHz or below 26.965 MHz.

No CB channel is assigned to any specific individual or organization. Be cooperative. Keep your communications short. Users must never talk with another station for more than 5 minutes continuously and then must wait at least one minute before starting another communication. Channel 9 is used only for emergency communications or for traveler assistance.

 

HOW A CB ANTENNA WORKS

 A citizens band (CB) radio antenna is a device designed to do two things: It captures radio-frequency signals that are then converted to electrical signals by the receiver, and it takes electrical signals from the transmitter and converts them into radio-frequency signals. This second function is where tuning comes into play, because an antenna has to radiate radio-frequency signals, something that's done best when the length of the antenna precisely matches the wavelength of the transmitted radio frequency.

You can determine the proper length of an antenna by using a formula:

Wavelength (in feet) = 984 / frequency (in megahertz)

The CB portion of the spectrum begins at 25.01 megahertz, so a full wavelength antenna would be a bit more than 39.34 feet long. That's obviously a little long to attach to your bumper, so people tend to use antennas that are a fraction of the wavelength: 1/2, 5/8, 1/4 and 1/8 are all common wavelengths for antennas. In the case of CB, the 1/4 antenna at just under 10 feet long is the common "whip" that you may see on cars and trucks.

The trouble is that there are 40 channels on modern CB transceivers, each corresponding to a different frequency. It's not practical to have a separate antenna for each frequency, so antenna designers have to compromise, usually picking a frequency in the middle of the spread and choosing the antenna length to correspond.

When a compromise like this is made, you have to see whether it's a good compromise. This is done by measuring the Standing Wave Ratio (SWR) of the antenna and cable between the antenna and tuning the antenna until the SWR is acceptable.

Every antenna and every antenna feed-line have a characteristic impedance, or opposition to electrical current. In an ideal situation, the impedances of line and antenna match perfectly, and 100 percent of the electrical energy sent to the antenna is converted to radio energy and radiated into the atmosphere. In a less than ideal case, when the impedances aren't perfectly matched, some of the electrical energy sent to the antenna won't be converted to radio energy, but will be reflected back down the feed-line. The energy reflecting back from the antenna causes standing waves of electrical energy in the feed-line. (An example of standing waves outside the electronics world is found in river rapids. When water passes around and between boulders it may form a wave that doesn't go up or down the river, it just stays in one place. That is a standing wave of water.) The ratio of highest voltage on the line to lowest is the standing wave ratio. In the perfectly matched system, the SWR is 1:1.

To tune an antenna, use an SWR meter attached between the transmitter and antenna feed-line. Depending on the meter, you can either use a button on the meter to generate a signal on the various channels, or key the microphone on the CB transceiver to generate a signal while you look at the SWR reading. In general, if the SWR never goes above 1.5:1, you're in good shape. If the SWR does go above 1.5:1, then watch the meter on different frequencies to see the trend develop: The SWR will be greater either on the higher channels or the lower. If the SWR is greater on the lower channels, then try gradually lengthening the antenna by moving it in the base. If the SWR is greater on the higher channels, try shortening the antenna.

Do be aware that the electrical ground of the antenna, the structure around the antenna and any other antennas near the CB antenna can all affect the antenna's impedance and the SWR. There are enough variables that tuning an antenna blends art and science, but your equipment and radio contacts will all be grateful if you take the time to tune up.

 

ADJUST YOUR SWR on your CB radio

Equipment needed: SWR meter, short jumper coax 3 foot.

Procedure:   The SWR meter needs to be placed in line between the antenna and the CB. Connect the antenna (normally connected to the back of the CB ) to the connector marked "Antenna" or "Ant"  on your SWR Meter. Connect one end of the short jumper coax to the "transmit" or "Xmit" on the SWR meter. Connect the other end of your jumper coax to the CB.

Assuming you have a standard SWR meter the switches should read as follows: REF or SWR, FWD, and there should be a slide switch marked "set" or "Adjust". If different consult your meter's owners manual.

With the radio on the lowest channel (1 on CB) and the SWR meters switch in the Forward (FWD) position, depress the transmit switch (key up) located on the microphone. While holding the unit in this transmit mode, adjust the meter needle to the set position using the Set or Adjust knob on the meter. As soon as the needle is in alignment with the corresponding mark on the meter face, flip the switch to the Reference (REF) position. The meter is now showing your SWR on channel one. Note the value and quickly release the microphone switch. Record this reading.

Repeat the previous step on channels 19 and 40.

How to read your results:  If SWR on channels 1, 19 & 40 is below 2.0, your radio can be operated safely.

If SWR on all channels is above 2.0 but not in the "red zone" (normally over 3.0), you may be experiencing coaxial cable reaction (bad quality, wrong length, etc.), insufficient ground plane, or have an ungrounded antenna mount.

If SWR is in the "red zone" on all channels, you probably have an electrical short in your coax connectors, or your mounting stud was installed incorrectly and is shorted. Do not operate your radio until the problem is found, serious damage can occur to your radio.

If SWR on the lowest channel is higher than it is on the highest channel, your antenna system appears to be electrically short. Your antenna length may need to be increased.

If the SWR on channel 40 is greater than that on channel 1, your antenna is considered to be "LONG" and reduction of physical height and/or conductor length will correct this situation.

How does an antenna size affect my CB radio?

If you put 4 watts into a four-foot antenna, you will get the same power out of that antenna as if you were putting 2 watts into a 102-inch whip.

If you put 4 watts into a 3-foot antenna you will get the same power out as if you wre putting about 1.5 watts into a 102-inch whip.

If you put 4 watts into a 7.5 inch antenna on a hand held CB, it would put out as much power as a third of a watt into a 102-whip.

If you put 4 watts into a 102-inch whip antenna, it is the same output as if you put 11 watts into a 3-foot whip.

If you put 4 watts into a 102-inch whip antenna,, it is the same as if you put 14 watts into a 28-inch antenna.

If you put 4 watts into a 102-inch whip antenna, it is the same as if you put 54 watts into a 7.5 antenna.

 What is a Citizen Band radio?

A Citizen Band Radio is an AM transceiver. A transceiver is a radio that can both transmit and receive. The "Band" part of Citizen Band refers to the "Bandwidth" or frequency range that has been reserved for use by your average citizen. You do not require a license to operate a CB which means anyone can pick one up and begin using it.

What do I need to operate on the Citizen Band?

First of all you will need an actual CB Radio. The CB radio itself can vary in size, function, and age. You can have a mobile (for your car), base (in your home), or handheld (in your hand) to choose from. For all CB's you will need some source of power. For a mobile this would be a 12 volt DC connection to your battery, for a Base you would usually have a plug for the 120V AC system, and most handhelds run on batteries. The last thing you need is an Antenna. They vary in size and function, and there are specific antennas for your car, home and handheld radios.

What do all the dials on the CB do?

Volume - Usually the on/off switch and volume of the internal speaker

Squelch - Helps you to adjust the radio to pick up only strong signals and shuts out the static that you will hear on most radios.

RF Gain - This adjustment can be used to adjust the strength of receive that a incoming signal has on your radio. If someone is right next to you and their radio is very loud you can turn down the RF gain and their signal will sound softer and their signal will register lower.

Mic Gain - Used to adjust the audio level of your voice into the radio.

ANL or NB - Used to cut out static on the radio

Fine Tune - Usually found on older radios, used to tune in the signal for clearer receptions

CH9 switch - Gives you instant access to channel 9, which often is considered as an emergency channel.

Meter - This shows you how strong an incoming signal is, or on some radios how strong your outgoing signal is, what your SWR is, or how your modulation is.

SWR/MOD/DX Switch - Many radios have self-diagnostics functions. Swr is used to measure the standing wave ratio (the lower the better), Mod measures your voice modulation (the higher the better, usually), RF measure the strength of your outgoing signal (the higher the better).

LSB/AM/USB - Often nicer radios have SSB or single sideband operation. SSB is a bit complicated to explain, but basically instead of putting out a signal and have your voice go for a ride on the signal as in AM, in SSB the voice takes a trip on its own. For every channel you have Upper and Lower Sideband, but can only talk on these with a SSB radio. Why use SSB? SSB radios put out up to 12watts of power instead of the regular 4 watts on AM and the SSB signals tend to go farther and pick up less static.

 Clarifier - Used for tuning in signals when operating on SSB.

 Roger Beep - Beeps at the end of your transmission to let other stations know you are done talking.

 Local/DX - Adjust output when transmitting for short or long distance.

I hooked up my CB and can hear people, but they can't hear me?

Often people who are bigger CB enthusiasts will have better CB set-ups, this means they will be able to talk farther and louder. Just as if someone has a louder voice, you may hear them from farther away. If you have a basic set-up, or possible something not set-up ideally or incorrectly, your signal (voice) will be very quiet and not heard from far away. Another case is "Skip" this occurs at different times of day and year. Skip is when signals from one area skip off the atmosphere and travel many many miles, often from the West Coast to the East Coast. You can be in Washington State and hear people talking in Alabama. Many times even though you can hear them, your signals won't bounce back to them so they can't hear you. YOU MAY ALSO WANT TO make sure all you connections are hooked up correctly and test to make sure you are actually transmitting a signal.

How long should my antenna be?

You may want to look at the antenna formula; it lists the formula for calculating the optimum length of Antenna. In a car, best bet is as long as possible without hitting power lines or trees :-). Most car set-ups will do best with a 102in antenna which is a wavelength antenna. Many Base stations antennas are 18' or longer, while most handheld antennas are on 8-10" high.

How do I tune my SWR, and how do I measure it?

You will need a SWR meter to measure your SWR. Radio shack carries a cheap meter that is usually effective enough. You want to get the SWR as low as possible. You can do this by lengthening or shortening your antenna. If you did not purchase an adjustable or tuneable antenna than you can try making adjustments by placing it in different locations and making sure it is grounded properly.

How can I boost the strength of my outgoing signal? Legal and Illegal options?

You can have your radio "tuned" by a CB technician to optimise its performance. You can also pick up a power mike (amplified microphone) to make sure your voice signal is at it's strongest point. There are other illegal options as well. You can purchase a linear amplifier for your CB, these boost the output signal of your radio and are installed in-line between the radio and antenna. The amps can boost your signal from 4 watts to 50 watts and some as much as 1000 watts or higher. Linears have many side effects though. They may distort your signal, they can cause a lot of interference with TV's radios and telephones (not just yours, your whole neighborhood). If you get caught using one the FCC reserves the right to fine you a lot of money too. So you would use one at your own risk. On the plus side, in many areas a linear is the only way to be heard by stations more than 5 miles away because terrain or other interference prevents your signal from going very far. Most people won't advertise linears for CB's since they are illegal, you will see many offered for 10 meter use though. These usually will also work for 11 meter operation. Also remember that although you might use a 250-watt amplifier they usually will only put out about the wattage they say they can. Lastly, be careful, high powerful linears can send out a very strong radio frequency, just like your microwave, it's not a good idea to stand right next to it for long periods of time. Touching an antenna that is transmitting even only a little extra wattage can cause a burn. We are not endorsing the use of linears, only describing what they are and how they are used. Use at your own risk.

Are you assigned a handle or can you make one up? What are the numbers for identification I hear people using?

You can call yourself whatever you want on the radio, try to be original. :-) Many people use #'s such as 484 or 292 instead of handles on the radio for easy identification. The numbers they are using are usually made up, sometimes they belong to a local club that may assign them, but feel free to use numbers if you wish.

Is it okay to talk to a station that is really far away if the skip allows it?

The FCC actually has set limits on how far you can legally transmit, but this is very rarely, if ever enforced. If you can talk far away, have fun and say hello to someone out there. Half the fun of amateur radio is making far off contacts. If you are using a Linear Amp to do this though, be careful as the FCC may be a little more interested if you are causing a lot of interference because your signal is too strong.

When I'm talking to someone, somebody else starts talking and interrupts our conversation. It causes a lot of humming and is really annoying. Can they do this?

CB radio is not regulated and therefore people often will do as they please. Dead Keying (transmitting a signal without talking) is fairly common as well as people just yelling all over the place. If they are located between you and the person you are talking to it will be very hard to have a conversation. The best bet is to try and find another channel to talk on and leave them alone. The humming or mixing of signals is called heterodyne. Try to observe good radio etiquette as it makes it more fun for everyone to use.

I notice when I'm up on a hill I can receive and transmit well, but when I'm in a valley I can't hear anyone?

Radio signals like to bounce around, as well as they like to shoot straight out from where you are transmitting. Imagine your radio signals as water. If you pour water in a hole or valley, it stays in the valley. If you pour your water directly over the center of a hill, it will flow out in all directions. This is pretty much the way radio signals tend to act.

What are no ground antennas?

Often on cars or motorhomes people can't find a good piece of metal to attach their antenna to. The metal is necessary to "ground" the antenna. Companies make special antennas for just those situations that don't require a ground. They often lose a little edge in performance, but better something than nothing.

 

CB Frequencies - AM Channels

Channel
No.

Band A

Band B

Band C

Band D

US CB Standard

Operating

Frequencies

Band E

Band F

1

25.615

26.065

26.515

26.965

27.415

27.865

2

25.625

26.075

26.525

26.975

27.425

27.875

3

25.635

26.085

26.535

26.985

27.435

27.885

4

25.655

26.105

26.555

27.005

27.455

27.905

5

25.665

26.115

26.565

27.015

27.465

27.915

6

25.675

26.125

26.575

27.025

27.475

27.925

7

25.685

26.135

26.585

27.035

27.485

27.935

8

25.705

26.155

26.605

27.055

27.505

27.955

9

25.715

26.165

26.615

27.065

27.515

27.965

10

25.725

26.175

26.625

27.075

27.525

27.975

11

25.735

26.185

26.635

27.085

27.535

27.985

12

25.755

26.205

26.655

27.105

27.555

28.005

13

25.765

26.215

26.665

27.115

27.565

28.015

14

25.775

26.225

26.675

27.125

27.575

28.025

15

25.785

26.235

26.685

27.135

27.585

28.035

16

25.805

26.255

26.705

27.155

27.605

28.055

17

25.815

26.265

26.715

27.165

27.615

28.065

18

25.825

26.275

26.725

27.175

27.625

28.075

19

25.835

26.285

26.735

27.185

27.635

28.085

20

25.855

26.305

26.755

27.205

27.655

28.105

21

25.865

26.315

26.765

27.215

27.665

28.115

22

25.875

26.325

26.775

27.225

27.675

28.125

23

25.885

26.335

26.785

27.235

27.685

28.135

24

25.895

26.345

26.795

27.245

27.695

28.145

25

25.905

26.355

26.805

27.255

27.705

28.155

26

25.915

26.365

26.815

27.265

27.715

28.165

27

25.925

26.375

26.825

27.275

27.725

28.175

28

25.935

26.385

26.835

27.285

27.735

28.185

29

25.945

26.395

26.845

27.295

27.745

28.195

30

25.955

26.405

26.855

27.305

27.755

28.205

31

25.965

26.415

26.865

27.315

27.765

28.215

32

25.975

26.425

26.875

27.325

27.775

28.225

33

25.985

26.435

26.885

27.335

27.785

28.235

34

25.995

26.445

26.895

27.345

27.795

28.245

35

26.005

26.455

26.905

27.355

27.805

28.255

36

26.015

26.465

26.915

27.365

27.815

28.265

37

26.025

26.475

26.925

27.375

27.825

28.275

38

26.035

26.485

26.935

27.385

27.835

28.285

39

26.045

26.495

26.945

27.395

27.845

28.295

40

26.055

26.505

26.955

27.405

27.855

28.305



 

UK CB Frequencies - FM Channels

Channel No.

Frequency

Channel No.

Frequency

1

27.60125

21

27.80125

2

27.61125

22

27.81125

3

27.62125

23

27.82125

4

27.63125

24

27.83125

5

27.64125

25

27.84125

6

27.65125

26

27.85125

7

27.66125

27

27.86125

8

27.67125

28

27.87125

9

27.68125

29

27.88125

10

27.69125

30

27.89125

11

27.70125

31

27.90125

12

27.71125

32

27.91125

13

27.72125

33

27.92125

14

27.73125

34

27.93125

15

27.74125

35

27.94125

16

27.75125

36

27.95125

17

27.76125

37

27.96125

18

27.77125

38

27.97125

19

27.78125

39

27.98125

20

27.79125

40

27.99125

 

CB RADIO 10 Codes

10-1     Receiving Poorly
10-2     Receiving Well
10-3     Stop Transmitting
10-4     Ok, Message Received
10-5     Relay Message
10-6     Busy, Stand By
10-7     Out of Service, Leaving Air
10-8     In Service, subject to call
10-9     Repeat Message
10-10   Transmission Completed, Standing By
10-11   Talking too Rapidly
10-12   Visitors Present
10-13   Advise weather/road conditions
10-16   Make Pickup at...
10-17   Urgent Business
10-18   Anything for us?
10-19   Nothing for you, return to base
10-20   My Location is ......... or What's your Location?
10-21   Call by Telephone
10-22   Report in Person too ......
10-23   Stand by
10-24   Completed last assignment
10-25   Can you Contact .......
10-26   Disregard Last Information/Cancel Last Message/Ignore
10-27   I am moving to Channel ......
10-28   Identify your station
10-29   Time is up for contact
10-30   Does not conform to FCC Rules
10-32   I will give you a radio check
10-33   Emergency Traffic at this station
10-34   Trouble at this station, help needed
10-35   Confidential Information
10-36   Correct Time is .........
10-38   Ambulance needed at .........
10-39   Your message delivered
10-41   Please tune to channel ........
10-42   Traffic Accident at ..........
10-43   Traffic tieup at .........
10-44   I have a message for you (or .........)
10-45   All units within range please report
10-50   Break Channel
10-62   Unable to copy, use phone
10-62sl   unable to copy on AM, use Sideband - Lower (not an official code)
10-62su  unable to copy on AM, use Sideband - Upper (not an official code)
10-65   Awaiting your next message/assignment
10-67   All units comply
10-70   Fire at .......
10-73   Speed Trap at ............
10-75   You are causing interference
10-77   Negative Contact
10-84   My telephone number is .........
10-85   My address is ...........
10-91   Talk closer to the Mike
10-92   Your transmitter is out of adjustment
10-93   Check my frequency on this channel
10-94   Please give me a long count
10-95   Transmit dead carrier for 5 sec.
10-99   Mission completed, all units secure
10-100   Need to go to Bathroom
10-200   Police needed at ..........

Amateur Radio Q Codes Commonly used on CB SSB

CQ - "Seek you." General call.

CQ DX - Seek contact with any distant station(s).

QRA - What is the name of your station? / The name of your station is _____.
QRG - Tell me the exact frequency.
QRH - Does frequency vary?
QRI - How is the tone of the transmission?
QRK - Readability of the signal is ...........
QRM - Man made interference. "QR Mary".
QRN - Natural interference/static. "QR Nancy".
QRO - Increase power.
QRP - Decrease power.
QRQ - Send faster.
QRS - Send slower.
QRT - Stop sending/off the radio.
QRU - Do you have anything for me?
QRV - Are you ready? I am ready.
QRW - I am calling on this frequency ............
QRX - What is the next schedule?
QRZ - Who is calling?
QSA - What is the signal strength?
QSB - Is my signal fading?
QSD - Is my keying defective?
QSG - Send .... message(s) at a time.
QSL - Acknowledge receipt.
QSM - Repeat last message.
QSO - Communicate directly or through a relay.
QSP - Will you relay to .............. ?
QSV - Send a series of V's.
QSW - Will you send on this frequency?
QSX - Shall I switch to another frequency?
QSY - Switching frequencies.
QSZ - Send each group twice.
QTA - Cancel message.
QTB - Do you agree with the number of words?
QTC - How many messages do you have to send?
QTH - Location.
QTR - Exact time.