All About Two-Way Radios
This article on 2-way radios by Bill Principe was written in 2001 for CALBIRD,a now-defunct RBA listserv on the internet.  I like this article because Bill explainsin a little more detail just what these radios are.  I am posting this article here on our webpage with permission from the author.

In Sea & Sage, we often use these handy little gadgets on our weekend field trips when driving from spot to spot as well as when we are on foot birding in unfamiliar territory.  The radios are a  big help in keeping the group together, sharing sightings of birds along the way, clarifying directions to the next stop, or notifying others of problems.  We also use them on school tours at the San Joaquin Wildlife Sanctuary and during other outdoor education programs.

Many birders use these radios to alert fellowbirders about the location of interesting birds.  When used for this purpose, the radios are set for  11- 22.



 
As a licensed Amateur Radio operator most of my life, I understand something about FRS, and I thought I would post a short message, so everyone knows what these radios are all about.
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Family Radio Service is authorized by the FCC to use radios with 1/2 watt of power, in the 460 MHz range. There are 14 channels in the band, and the better radios have all 14. Some offer only 7 or even 1 or 2. The exact frequency of channel 8 is 467.5625 MHz.
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For comparison, CB radios are 5 watts and operate at 27 MHz. The FM broadcast band is 88-108 MHz.
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All FRS radios, no matter what brand, have the same power and frequency ratings.
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FRS radios only work over a short line-of-sight range, never more than about 2 miles. They are not  really "line of sight," and the signal can be absorbed by vegetation, buildings, or even heavy weather. A practical limit for the radios is usually about 1 mile.
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A good antenna helps. The units with small antennas that stick up are better than units with hidden, built-in antennas. Our radios, Cobras, have fold-down antennas, which are handy when range is not important.
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The "privacy codes" are actually CTCSS codes, which stands for Continuous Tone Coded Squelch System. If you don't want a technical explanation, skip the next paragraphs.
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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.
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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. But it is pretty good.
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John Wilson said he was concerned about compatibility between CTCSS, or privacy, codes. I checked, and he has a valid point. Older radios may use different numbers for the same code, so that a Motorola may have to use 18 to talk to an Unwired on code 17. However, the newer radios are standardized. If it turns out that you have a problem, a little expermentation may help you discover the correct CTCSS code. I suspect that most of us will have newer radios and will not have a problem.
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What brand should you buy? They should all be pretty much the same. Make sure you buy a 14 channel unit, and if we decide to standardize on 8-18, then make sure you have CTCSS codes on your radio. If you are unsure that they are the standard codes, take along a friend's Motorola or Kenwood
radio, and see if it can talk to the radio you want to buy.
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While all radios should talk to one another, I have found that the "Call" buttons may not work from brand to brand. But this may not be an important feature for you. (When you push "Call," the other guy's radio warbles or rings. Some birders feel this noise disturbs the birds.)
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A fold down antenna is best, but an external antenna is a necessity for good reception. Don't buy a unit with a hidden built-in antenna.
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Some people prefer AA battery units to AAA units, because AA batteries are cheaper. But AAA units are smaller and lighter. Your pick!  (Since this article was written, some radios have come out with rechargeable batteries.)
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Some models have an FM broadcast receiver on them. Probably not a good feature for birders. Our radios have the Weather channel, which IS useful. Some models allow you to plug in a "speaker-mike," like the mikes you may see on cops' shoulders. I haven't tried them, but they might be useful for birders.
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Don't forget that these radios have uses beyond birding. Kathleen and I use them when we shop at large stores like Fry's or Costco. We have also used them in car caravans.
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Anyway, FRS is a great solution for birding. We have been waiting for this technology for years! Anyone who has used these radios, and been able to "come runnin'" when the bird shows up, knows that they are well worth the small investment. Standardizing on a "birders' code" will pay off in great birds and fun birding!
Bill Principe

 
 
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