Family Radio Service
From Wikipedia, the free encyclopedia
The Family Radio Service (FRS) is an improved walkie talkie system authorized in the United States since 1996. This personal radio service uses channelized 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 also used by cordless phones, toys, and baby monitors. FRS uses frequency modulation (FM) instead of amplitude modulation (AM). Since the UHF band has different radio propagation characteristics, the short range use of FRS may be more reliable than license-free radios operating in the HF CB band.
Initially proposed by Radio Shack in 1994 for use by families, FRS has also seen significant adoption by business interests, as an unlicensed, low-cost alternative to the business band.
Contents |
[edit] Technical information
FRS radios are limited to 500 milliwatts in the U.S., according to FCC regulations. Channels 1 to 7 are shared with low-power interstitial channels of 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 sub-audible tone squelch (CTCSS and DCS) codes, filtering out unwanted chatter from other users on the same frequency. Although these codes are sometimes called "privacy codes" or "private line codes" (PL codes), they offer no protection from eavesdropping and are only intended to help share busy channels. Tone codes also do nothing to prevent desired transmissions from being swamped by stronger signals having a different code.
FRS stations on channels 1 through 7 may communicate with GMRS stations on those channels; the GMRS stations may use up to 5 watts of power, while the FRS stations are restricted to 0.5 watts.
The use of duplex radio repeaters and interconnects to the telephone network are prohibited under FRS rules, unlike in GMRS (where repeaters, but not telephone interconnects, are permitted), and the Amateur Radio Service. FRS radios must use only permanently-attached antennas. This limitation intentionally restricts the range of communications, and promotes sharing of the available channels.
FRS manufacturers generally claim an effective range of 3 km (2 miles) or more, but actual performance is limited by the physics of propagation. The presence of large buildings can reduce range. Under exceptional conditions, such as hilltop to hilltop, communication is possible over 50 km (30 miles) or more. Under normal conditions, however, with line-of-sight blocked by a few buildings or trees, FRS generally has an effective range of 0.5 to 1.5 km (1/3 to 1 mile).
[edit] FRS/GMRS Dual Service Radios
Recently, hybrid FRS/GMRS consumer radios have been introduced that have 22 channels. Many of these radios have been certified for unlicensed operation (on the 14 FRS frequencies) under FRS rules. [1]
The FCC rules and statements regarding the use of hybrid radios on channels 1-7 stipulate the need for GMRS licensing only when operating under the rules that apply to the GMRS. Many hybrid radios have an ERP that is lower than 0.5 watts on channels 1-7, or can be set by the user to operate at low power on these channels. This allows hybrid radios to be used under the license free FRS rules if the ERP is less than 0.5 watts AND the unit is certified for FRS operation on these frequencies.
Owners of dual-service radios should be aware that it is unlawful to operate on channels 15-22 at any power level without holding a valid, FCC-issued GMRS license in the United States of America. In practice, however, many radio manufacturers do not make this distinction sufficiently clear to customers. Consequently, this often leads to unlawful interference to GMRS licensees by others that erroneously believe they are simply using additional FRS channels. As GMRS licenses cost money to obtain, such interference can often be a source of frustration for duly-licensed operators.
Channels 8-14 are reserved exclusively for the FRS, and GMRS operation is not allowed on these channels.
Channels 15-22 are reserved exclusively for GMRS, and FRS operation is not allowed on these channels.
[edit] List of FRS channels
| Channel | Frequency (MHz) | Notes |
|---|---|---|
| 1 | 462.5625 | Unofficially designated the National Call Channel. Shared with GMRS. |
| 2 | 462.5875 | Shared with GMRS. |
| 3 | 462.6125 | Shared with GMRS. |
| 4 | 462.6375 | Shared with GMRS. |
| 5 | 462.6625 | Shared with GMRS. |
| 6 | 462.6875 | Shared with GMRS. |
| 7 | 462.7125 | Shared with GMRS. |
| 8 | 467.5625 | FRS use ONLY (GMRS not allowed) |
| 9 | 467.5875 | FRS use ONLY (GMRS not allowed) |
| 10 | 467.6125 | FRS use ONLY (GMRS not allowed) |
| 11 | 467.6375 | FRS use ONLY (GMRS not allowed) |
| 12 | 467.6625 | FRS use ONLY (GMRS not allowed) |
| 13 | 467.6875 | FRS use ONLY (GMRS not allowed) |
| 14 | 467.7125 | FRS use ONLY (GMRS not allowed) |
[edit] Similar services in other regions
Personal UHF radio services similar to the American FRS exist in other countries, although since technical standards and frequency bands will differ, usually FCC-approved FRS equipment may not be used in other jurisdictions.
[edit] Canada
American-standard 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 FRS/GMRS radios have also been approved for use in Canada, giving additional channels. In Canada only no license is required to use the GMRS shared channels 15 through 22.
[edit] Mexico
Since tourists often bring their FRS radios with them, and since trade between the U.S., 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 FRS/GMRS equipment is not approved in Mexico, so caution should be exercised in operating those hybrid FRS/GMRS devices purchased elsewhere.
[edit] Europe
In Europe, a personal radio service with the same sort of licensing restriction is PMR446 having eight channels in the 446MHz range. One cannot legally use the FRS radio in Europe or PMR446 in the U.S. 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 U.S. in compliance with the rules for amateur radio operation. In Great Britain, FRS frequencies are used for fire brigade communications and this sometimes causes problems when FRS equipment is imported from the U.S. and used without awareness of the consequences by members of the public.
[edit] South America
Dual-mode GMRS/FRS equipment is also approved in Brazil and most South American countries. Portable radios are heavily used in private communications, mainly by security staff in nightclubs and malls, but also in private parking, maintenance, and delivery services.
[edit] China
A service similar to the American-style FRS in Hong Kong, Macau, and China is also approved by respective organizations for legal license-free operation. However, different UHF frequencies with 20 allocated channels near 409 MHz are used. 462 MHz and 446 MHz band are not opened to FRS service, so European, American, and Canadian residents are advised not to use FRS or PMR446 radios for communication when traveling to the aforementioned areas.
[edit] Japan
In Japan, a similar service uses low-power in the 420, 421, and 422 MHZ bands. It is called "Tokutei Shoudenryoku Musen" ("SLPR:Specified Low Power Radio").
[edit] Australia and New Zealand
In Australia and New Zealand, the UHF CB citizen's band near 477 MHZ is used for a similar purpose.
[edit] See also
[edit] References
[edit] External links
- CTCSS Codes for some Radios
- FRS Radios in Mexico
- Industry Canada discussion on the approval of FRS in Canada
- Personal Radio Association
- FRS and GMRS radio information and forums
- F-R-S Communications Center
- The situation of License Free Radio System in Japan
|
||||||||||||||||||||
