About Family
Radio Service (FRS)

Sierra Club / Audubon is increasingly using an inexpensive standard FRS (Family Radio Service) or FRS/GMRS radio afield. This kind of common communications is often very helpful when driving in multiple vehicles or when spread out in multiple parties or meeting. On bird outtings we use a common channel and subcode: 11/22. On trips of other interest, check with the leader.

FRS radios have a communications range of about 1/2 mile. For comparison, CB radios are 5 watts and have up to 4 mile range.

What brand should you buy? My preference is Motorola or Kenwood. Otherwise they should all be pretty much the same for less demanding needs. Make sure you buy a 14 channel unit with 38 Privacy Codes.

"Call" buttons may not work from brand to brand (When you push "Call," the other guy's radio warbles or rings. Some birders feel this noise disturbs the birds.).

Many are now comming with rechargable batteries only, some give you both options. I have a voltage inverter setup (converts 12 DC volt outlet to 120 volts AC) in my car that I can use to keep all my batteries charged on car trips. There are solar options, but I don't find them convient for backpacking.

License documents are neither needed nor issued for FRS.

Tech Notes

Range of FRS radios can vary for many reasons. Manufactures ratings are exaggerated and are theoretical limits. Good design is better than more power. Most will work fine for our outtings.The line of sight ratings are incorrect as trees, mountains, buildings can absorb the signal. Antenna types are important, the type that is short and built-in may be convenient but not as good as an external car top mounted or base antenna.

Privacy codes are actually CTCSS codes, which stands for Continuous Tone Coded Squelch System. There are 38 possible CTCSS codes. CTCSS code 18 is 118.8 Hz, a low rumble that you should not be able to hear on your speaker. . All FRS radios have "squelch," which turns off the audio (usually static) when no one is transmitting. Without CTCSS, any signal will "break the squelch," and you will hear anyone transmitting on the channel within your range. With CTCSS turned on, your radio must "hear" a sub-audible tone to "break the squelch." If the other radio transmits the tone, your radio will give you the signal. Otherwise, your radio will stay silent. That way, several sets of radios can "share" a channel, and minimize interference. BUT . . . if two people with different CTCSS codes transmit at the same time, your radio may or may not hear both or either signals, so it is not truly channel sharing. The early implementation of CTCSS codes standards were inconsistant, in groups with older radios, it is best to not use privacy codes.

FRS/GMRS Dual Service Radios or "hybrid" radios: FRS/GMRS 2-way radios are simply dual-service, or "hybrid," radios that provide access to both the FRS and GMRS bands, utilizing FRS channels (1-14) and GMRS channels (15-22). Use of a dual-service radio’s GMRS bands requires an FCC operator’s license. Dual-service radios may be used without an operator’s license, if only the FRS channels are used. FRS radios have a maximum power of ½ watt (500 milliwatt) effective radiated power and integral (non-detachable) antennas. If you operate a radio under the rules that apply to GMRS, you must have a GMRS license. GMRS radios generally transmit at higher power levels (1 to 5 watts is typical) and may have detachable antennas.

GMRS or General Mobile Radio Service radios operate on any of up to 8 dedicated channels (15-22) designated by the FCC. GMRS radios typically have power ratings of 1.0 to 5.0 watts and have a maximum allowable power of 50 watts.

GMRS radios are very similar to FRS radios, except for a few important distinctions:
1) GMRS radio use requires you to purchase an FCC operator’s license.
2) GMRS radios generally achieve greater ranges than FRS radios.
3) While FRS radios may not legally be altered, GMRS radios may legally be outfitted or retrofitted with optional antennas, car antennas or home antennas to extend their range.