Under Construction
Type Name Freq Band Dist-
ance (Mi.) 1
Power License
Max Pwr
CB Citizens Band 27 MHz HF 2-5   4 2 none
49 MHz 49 MHz 80 millivolts/m   4 2 none
MURS Multi-Use Radio Service 150 MHz VHF     2 none
Marine   156 MHz        
IG Industrial/Business 169 MHz       IG
IG Industrial/Business 451-467 UHF       IG
FRS Family Radio Service 462-467 MHz 1/2 - 2 0.5 0.5 none
GMRS General Mobile Radio Service 462-467 MHz 1-4 2-5 50 ZA
Ham Amateur Radio many all 10-1,000s 5-50 1500 HA
1. Distance depends on terrain and antenna. A CB with a car antenna can go up to 5 miles between cars with antennas. A handheld CB may be lucky to go 1 mi.
Consumer Reports tests of GMRS worked well in a mall and went up to 1.5 mile in a suburban neighborhood. See Personal Radio in Products.
2. CB can go up to 12 watts for SSB (Single sideband).

See radio channel frequencies for CB, Marine, FRS, GMRS

The FCC rules and regulations are codified in Title 47 of the Code of Federal Regulations (CFR)

the 49 MHz band is used by cordless phones, toys, baby monitors and motorcycle helmet intercomms.

The Family Radio Service (FRS) is an improved walkie talkie system authorized in the United States since 1996. These are the $20-60 per pair radios available at radio shack, target, staples, costco, ...). They are popular with hikers and skiers.

General Mobile Radio Service (GMRS) shares frequencies with FRS and is now commonly included in the FRS handheld radios. Higher power GMRS radios (base station radios with detachable antennas) are also used commercially.
GMRS requires a FCC License ($85 for 5 years) to go over 1/2 watt.
3 watt GMRS radios advertise 8 miles on land and 10 mi. over open water;
5 watt units advertise 10-14 mi. distances. These are theoritecal under ideal conditions. Typical distances are more like 1 mi. See products.

This personal radio service uses frequencies in the ultra high frequency (UHF) band, and so does not suffer the interference effects found on citizens' band (CB) at 27 MHz, or the 49 MHz band. They uses frequency modulation (FM) instead of amplitude modulation (AM), and has a greater reliable range than license-free radios operating in the CB or 49 MHz bands.

REACT (Raqdio Emergency Associated Citizens Team) are volunteers who monitor channel 9 on CB's and channel 20 on GMRS to report problems by travelers.

Ch Freq  Ch Freq
1 462.5625 8 467.5625
2 462.5875 9 467.5875
3 462.6125 10 467.6125
4 462.6375 11 467.6375
5 462.6625 12 467.6625
6 462.6875 13 467.6875
7 462.7125 14 467.7125
15 462.550 467.550
16 462.575 467.575
17 462.600 467.600
18 462.625 467.625
19 462.650 467.650
20* 462.675 467.675*
21 462.700 467.700
22 462.725 467.725
1. FRS Channels 1-7 can be used for GMRS (5 w)
2. Second set of GMRS frequencies is for duplex (repeater) operation.
* Nationwide emergency and road information calling. Nationally recognized coded squelch for 675 emergency repeater operation is 141.3 Hz.

See Wireless Services at the FCC

Types of Communications:
Trail Communications

Installation of Ham and CB radios:
Power Supply:
A few of the components that have been found to cause interference to radios include the engine computer, wiper delay module, electric fuel pump, dash panel gauges, and even the digital clock in the AM/FM radio.
If you tap into the wiring that directly supplies these components, you increase chance of getting RF noise on the power leads going to your radio.

Power Wiring
Power requirements range for less than 1 amp. for some scanners to 20 amps for an com IC-706MKII-G.

Anderson Power Pole connectors are popular.

Radio Power Distribution System Installation

One of the web installation guides (below) recommends using the blue wire behind the glove box on 1997-1999 TJs. That works but gives iterference when the rear window defroster or wiper is on. See:
Jeep TJ CB Radio Install at off-road.com
Installation of a Ham Radio
Installing a Cobra 75WXST at 4x4xplor.com
Mobile Radio Install Tips
Installation in Emergency response jeep NMO antenna mounts, and I really like the Tram 1180 dual-band (2m/70cm) mobile antenna. FireStik CB antenna.
Noise Abatement
Antenna mount accessories at FireStick

CB Stuff
Channel 9 (27.065 MHz)- Emergency 14 (27.125) & 19 (27.185 MHz) may also be used.
Channel 10-23 - the trucking industry makes good use of CB Radio by constantly using and monitoring specific frequencies, usually those between Channel 9 and Channel 23.
Channel 10 (27.075 MHz) - Used by off-road vehicles on the Rubicon Trail
Channel 4 or 16 - Used by many 4X4 clubs (4x4=16)
Channel 12 used by tri-state 4x4
Channel 19 (27.185) - Most truckers monitor this.
Channel 17 (27.165 MHz) - Used by truckers for North-South routes (I-5) in Calif.
Channel 21 (27.215 MHz)- Used by truckers for North-South routes in some places.

1) 26.965 MHz 9) 27.065 MHz 17) 27.165 MHz 25) 27.245 MHz 33) 27.335 MHz
2) 26.975 MHz 10) 27.075 MHz 18) 27.175 MHz 26) 27.265 MHz 34) 27.345 MHz
3) 26.985 MHz 11) 27.085 MHz 19) 27.185 MHz 27) 27.275 MHz 35) 27.355 MHz
4) 27.005 MHz 12) 27.105 MHz 20) 27.205 MHz 28) 27.285 MHz 36) 27.365 MHz
5) 27.015 MHz 13) 27.115 MHz 21) 27.215 MHz 29) 27.295 MHz 37) 27.375 MHz
6) 27.025 MHz 14) 27.125 MHz 22) 27.225 MHz 30) 27.305 MHz 38) 27.385 MHz
7) 27.035 MHz 15) 27.135 MHz 23) 27.255 MHz 31) 27.315 MHz 39) 27.395 MHz
8) 27.055 MHz 16) 27.155 MHz 24) 27.235 MHz 32) 27.325 MHz 40) 27.405 MHz
Remote Control devices: 3A-26.995 MHz, 7A-27.045, 11A-27.095, 15A-27.145, 19A-27.195

See Channel usage

Power, SSB
CB Radio operators normally transmit double sideband AM on the first 23 channels. On channels above Channel 23, upper sideband or lower sideband equipment may be used. Four watts of carrier power is allowed for output on AM, and 12 watts of peak envelope power is the maximum power output on SSB.

Radio Codes (Ten-Codes, 10-4, ...)

Scanners are popular for listening to police, fire, marine and other radio transmissions.
There are laws about how this information can be used. In New York, for example, the state with the most restrictive scanner law, possession of a scanner is illegal without a permit.

Police and other municipal organizations in larger cities are using more sophisticated radios that use trunking primairly in the 800-MHz band. No service is assigned a specific frequency. Each department identified by an ID called a talkgroup. A computer selects the next unused frequency and assigns it to a talkgroup. Scanners which contain computers to handle trunking systems are more expensive.


CB - Citizens Band
CFR - Code of Federal Regulations
CW   - Continuous Wave - common usage refers to Morse code
FCC  - Federal Communications Commission
FRS  - Family Radio Service
GMRS - General Mobile Radio Service
PRSG - Personal Radio Steering Group
PA   - Power amplifier
USB  - Upper Side Band
VOX  - Voice operated transmit

Guide to Emergency Survival Communications by Dave Ingram, 1999

Monitoring TImes
Popular COmmunications
Radio World
73 Amateur Radio Today
Wireless Services at the FCC
Electromagnetic Spectrum
Personal Radio in Products
Radio Modes and Modulation
Antenna Types and Installation
Emergency Communicataions (Ham, Cell Phone, Satellite Phone, CB) at Lake Tahoe

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last updated 26 Oct 2006