Science Fair Project Encyclopedia
Family Radio Service
The Family Radio Service is an improved walkie talkie system authorized in the United States. This personal radio service uses frequencies in the UHF band, and so does not suffer the interference effects found on Citizens Band (CB) at 27 MHz, or the 49 MHz band also used by cordless phones,toy walkie-talkies, and baby monitors. FRS uses FM instead of AM, and has a greater reliable range than license-free radios operating in the CB or 49 MHZ bands.
FRS radios are limited to 500 milliwatts in the U.S., according to FCC regulations. Channels 1 to 7 are shared with GMRS, the General Mobile Radio Service. A license is required for those channels only if the power output is over FRS limits, up to GMRS limits. Unlike Citizens' Band (CB) radios, FRS radios frequently have provisions for using CTCSS codes, allowing for more private conversations by filtering out unwanted chatter on the same frequency. The use of repeaters and interconnects to the PSTN are prohibited, unlike in GMRS. FRS radios must use only permanently-attached antennas, which restricts the range of communication but also limits interefence to other users.
FRS manufacturers generally claim an effective range of 3 km (2 miles) but this varies widely. The presence of large metal buildings can reduce range, but hobbyists have found that under exceptional conditions (hill-top to hill-top) communication is possible over 50 km (30 miles) or more.
FRS in Other Countries
FRS radios have been approved for use in Canada since April 2000. The revised technical standard RSS 210 has essentially the same technical requirements as in the United States. Since September 2004 low-power GMRS radios and dual-standard GMRS/FRS radios have also been approved for use in Canada, giving additional channels.
Since tourists often bring their FRS radios with them, and since trade between the US, Canada, and Mexico is of great value to all three countries, the Mexican Federal Telecommunications Commission has authorized use of the FRS frequencies and equipment similar to that in the US. However, dual-mode GMRS/FRS equipment is not approved in Mexico, so caution should be exercised in operating FRS devices purchased elsewhere.
FRS is an American description. In Europe, a similar service with the same sort of licensing restriction is PMR446 having eight channels in the 446MHz range. Thus one cannot legally use the FRS radio in Europe or PMR446 in the USA. The 446 MHZ band is allocated to amateur radio in the United States, so in principle a licensed amateur operator could use non-FCC-type-accepted PMR446 radios in the US in compliance with the rules for amateur radio operation.
FRS services are available in Brazil and other South American countries.
List of Channels
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