Search and Rescue

Basic Radio Communications

by Mike Dugger


What is the most important piece of gear for a SAR team in the field? Many SAR volunteers would answer "a radio." A radio is the team's vital link to base camp, permitting communication of located clues, progress on an assignment, changes in strategy, or location of the subject. While searching without a radio is certainly possible, the ability to communicate with teams in the field is a great source of comfort for both the searcher and the incident command staff at base camp. This mini-lesson is intended to provide a few basic guidelines to promote effective communications.


Since this lesson is geared toward searchers in the field, hand-held or "handy talkies" are stressed, but many of these issues apply to vehicle mounted radios or base stations as well. There are two basic kinds of handy talkies: crystal or programmable (AKA "synthesized"). For each frequency on which the radio operates, crystal radios have one crystal for the transmitter and one for the receiver. Since SAR operations frequently make use of multiple frequencies, and these may change from mission to mission, programmable radios are popular. A selectable "high" or "low" power setting is a good idea, to help conserve precious battery life when high power is not needed. Always carry a backup battery. Some users prefer to carry a couple of long life batteries (1200 mA.hrs, for example), and others prefer battery pack adapters that can accept AA size alkaline batteries.

"PL tone," or CTCSS (continuous tone coded squelch system) programmability is a useful option. Some repeaters are closed and require a special sub-audible tone to get access, or to access special features such as a patch into the telephone system. Repeaters used in SAR missions are usually put in emergency operating mode, in which the PL tone is disabled. The PL tone may still be required to access the phone patch. Alternatively, the communications specialist or other member of the command staff is usually willing to make an emergency telephone call for you from base camp if necessary. If you are interested in accessing a repeater's phone patch, you will also need a DTMF keypad on your radio. This keypad provides the 12 standard tones (0-9, * and #) used by the telephone system to dial phone numbers.

A radio capable of storing several operating frequencies is a good idea. You can then change from one frequency to another by simply turning a knob or pressing a button. Opinions vary on how many channels are necessary. On any mission (even a large one) it is unlikely that more than six separate frequencies will be needed for field personnel (main mission frequency, your team plus two other team frequencies, weather, and a repeater). The communications specialist at base camp may use several more. Some people find it convenient to program their radio with a larger number of SAR and repeater frequencies and then not have to program their radio as often. This is a matter of personal preference. If you have a field programmable radio and are comfortable doing so, you can buy a radio with fewer channels.

Radio Operation

You should be very familiar with the basic functions of the radio BEFORE heading out into the field. A few additional pointers follow, acquired from mission experience.

Use of a speaker microphone allows the radio to be kept warm (improved battery life), dry, and protected while only the microphone is exposed to the elements. When using a speaker microphone, it is a good idea to lock the radio keyboard. Buttons accidentally pressed won't mess up your radio settings while your radio is riding in your pack or harness. If you can't hear or be heard, check your antenna - this connection frequently makes for poor signal transmission and is another important reason to do a radio check when you are about 1/2 mile from base camp. If your radio is not working properly, you may therefore return to base to get things fixed without wasting too much time. In addition to the initial radio check, teams should check in periodically with base camp to inform them of progress and that the teams are still in communication range. Unless instructed by Incident Base to check in at some other interval, it is good practice to check in about every hour. Even if monitoring other frequencies in addition to the mission frequency, NEVER go off the mission frequency or turn off your radio without informing Incident Base.

It is a good idea to scan mission frequencies, particularly while en route to base camp, so you don't miss any important traffic such as a find or change of base camp location. Remember to turn up the volume on your handy talkie when you use it inside a vehicle, so you can hear it over vehicle noise. The squelch control can be used to set the radio volume by turning down the squelch until you hear background static, then set the volume. If you do not hear static with the squelch all the way down and the volume up, this is an indication that something is wrong with the radio.

Always wait a second or two after keying the microphone before you begin speaking. This will give your transmitter (or the repeater) a chance to turn on before your information is transmitted. Failure to do this results in the first word or two in of the sentence being clipped off, and can be confusing for those listening to you. Also avoid yelling into the microphone or having it too close to your mouth, as this will distort your voice. Radios work best if you speak with the microphone a few inches from your mouth and at a volume used in normal conversation. If your transmission is broken or weak, yelling into the microphone is a normal reaction but will only make matters worse.

Signal Transmission

Radio signals are a form of electromagnetic radiation like light, and generally travel in a straight line. However, they can be bent by the atmosphere or layers of charged particles, and can reflect off of surfaces. For this reason, signal quality between two radios will be improved if these radios are on high points, with no ridges, trees or buildings between them. Although "directional" antennas can be used to preferentially transmit radio waves in a certain direction, radio waves are generally transmitted in all directions. Since radio waves can reflect, the signal arriving at your radio may be composed of two or more signals coming from the same source, but taking slightly different paths. One may travel directly to you from the transmitter's antenna, and another may reflect off of a cliff face before reaching you, for example. These two waves can interfere with one another and cause "dead spots" (nodes and anti-nodes created by interference of electromagnetic waves at the same or slightly different frequencies are beyond the scope of this lesson). A good strategy to improve signal clarity between two stations therefore includes moving to a local high spot, or if at a high spot, simply moving a few feet to cancel destructive interference if a reflected wave is disrupting communications. A higher power setting on your radio may improve the ability of another station to hear you, but will not improve how well you receive another station.

One trick that has been used when low battery power or extremely poor signal conditions prevent communication is to key the transmitter to produce a click. When someone's battery is going dead and they do not have a backup, or when there is too much interference to understand what someone is saying, the communications specialist may say something like "Is your battery low? Click once for yes and twice for no." The transmitter will usually have enough power to momentarily turn on and produce an audible click on the transmit frequency for a while after power is too low to transmit voice. In this way, the party in the field can pass information to base in the form of answers to simple questions. Remember - the goal is to convey information. If communications can be maintained for a while longer at a critical time with this method, it may be used. Of course you should always have a spare power source. If you lose all ability to communicate with base, you should immediately proceed to base or the nearest staging area that has communication with base.

Conveying Information

The purpose of any communication is to convey information. When on a SAR mission, WHAT to say is at least as important as HOW to say it. Any information worth transmitting by radio should be relevant to the mission and understood by the recipient. Speak slowly and in plain English, without "Q-codes," "10-codes," or jargon. Speaking slowly not only facilitates understanding of your message, but will be appreciated by anyone who may be keeping a written record of mission communications in base camp. This is particularly important when describing a clue or transmitting your coordinates in UTM or latitude-longitude. To make sure you are understood, it is entirely acceptable to ask, "Do you understand?" after transmitting your message. When initializing or responding to any communication on the radio, it is important to indicate who is calling whom. Use the words "this is" or "to." For example, the phrase "Team four to search base" might be answered with "This is search base. Go ahead team four."

The only exception to avoiding coded transmissions occurs in the case of fatality of the subject. It is important to remember that radio transmissions can be heard by ANYONE, and that there are usually other people listening to SAR radio communications than those participating in the mission. We want to let the Incident Commander (IC) or communications specialist know what is going on, without telling the rest of the world. We do not want family or friends of the missing person hear about their death first on the evening news. To prevent this, the IC will sometimes give a "death code" or "condition code," which is a special phrase to secretly let base camp know the condition of the subject. The death code may be a phrase such as "I found the lake," or "I found a red sneaker." In the excitement of initial attack, command staff may forget to issue a death code. It is good practice to ask for one before leaving base camp if you are not given one during briefing.

Since transmitter power and terrain features limit the range of radios, information will sometimes be relayed from one station to another until it reaches the intended party. For example, the Civil Air Patrol may relay information back and forth between a team in a remote canyon and incident base. Whenever relaying information, it is important that it be done word-for-word, exactly as transmitted by the sender. Any information added by the relaying station should be identified as such. This procedure is necessary to make sure the message maintains its original meaning from sender to recipient. Small changes in a relayed message may, after a few iterations, end up totally changing the meaning of the message.

Protocol & Radio Etiquette

The FCC (Federal Communications Commission) controls access to and use of radio frequencies throughout the United States. Similar agencies control radio transmissions in other countries. All radio frequency users must have a license to transmit on that frequency, issued by the FCC or appropriate governing agency. The only exception to this rule under FCC regulations is in a "life or death" emergency, when any frequency may be used to call for help. A search itself is generally not considered to be a life or death emergency, and frequencies used by incident command are used under an FCC-issued license. As a non-licensed SAR person, it is OK for you to use the frequencies designated by incident command for search information only, and only during the duration of the mission. Only licensed amateur radio operators may use frequencies other than the mission frequency, unless a life or death emergency exists. The FCC requires that frequency users identify themselves using their FCC-issued call sign at least every 30 minutes. Base camp usually takes care of this for frequencies in use on a SAR mission. [Ed. Note: US Amateur radio operators are required to state their callsign every 10 minutes during a contact and at the end of the contact. The 30 minute rule mentioned above applies to frequencies within the public service band, such as 155.160MHz (the New Mexico Emergency Services Council has the callsign KC7064, and the State Of New Mexico Radio Communications Bureau holds WNXV605 for this frequency) or 155.265MHz (Cibola has the callsign WPPU605 for this one). In the latter case, users of handheld radios are not required to state the callsign as long as a "base" operator is doing so every 30 minutes. As always, Cibola Search and Rescue does not guarantee that this information is current, and users of these services should consult appropriate federal regulations for definitive information. For reference, Amateurs are governed by Part 97 of Title 47 of the Code of Federal Regulations, and public service band licensees by Part 90.]

NEVER use a mission frequency to hold a non-mission related conversation, or to pass on "cute" remarks. The mission frequency must remain open as much as possible to permit the transfer of important mission-related information. For the same reason, keep mission-related communications to the minimum amount necessary. Consider whether the information you are about to transmit, such as that Pepsi can you just found, is really important before using up battery power to tell base camp (and everyone else on the mission) about it. It is interesting to note that compared to just being on, a radio consumes about 6 times as much power to receive and about 50 times as much power to transmit. [1] For the same reason, it is a good idea to use a frequency other than the main mission frequency to convey "tactical" information. For example, when two teams are trying to meet up in the field, or when a member needs directions to base camp, use a separate team frequency rather than the mission frequency. The key is to avoid unnecessary transmissions. When you do find yourself involved in a lengthy dialog on the mission frequency, it is good practice to pause momentarily after every few sentences. This allows someone with really important information to break in. There have been situations where teams have waited 15 minutes to report tracks or a clue while some conversation in process finished up. This new information might render the conversation in progress moot. If you need to break in with extremely urgent information, say "break, break, break" and identify yourself. Likewise, you should stop talking when you hear three rapid breaks. The only thing on the frequency after three breaks should be silence, awaiting transmission of the urgent information.

Turn your radio off or the volume low enough for only you to hear, while in the vicinity of base camp. Having dozens of radios blaring in base camp can be distracting for command staff, and also wastes battery power. Another consideration may be members of the media or the subject's family at base camp. The media should get their information from the Incident Commander or their Information Officer, and mission details may be upsetting to the subject's family.

Some SAR members become licensed amateur radio operators so that they can have access to other frequencies and repeaters to convey information. Repeaters extend the range of mobile radios by receiving and re-transmitting information at higher power, and licensed amateur radio operators usually have access to many repeaters in their area. A "technician" class license issued by the FCC is not too difficult to get, and permits access to several amateur radio frequency bands.

In the Incident Command System structure, the communications specialist reports to the Logistics Section Chief. Their job is to relay and record information, not to make tactical decisions. On larger missions that may use a communications specialist, realize that command decisions will require consulting with the incident commander. Be patient.

The use of profanity in a radio transmission is never acceptable. The FCC prohibits this behavior, and may impose a large fine. Amateur radio operators self-police their privilege to use amateur bands designated by the FCC, and will generally report anyone heard using profanity on the radio frequencies.


1. Bob Cowan, "Communications Guide for the New SAR Person," in the 1997 New Mexico Field Certification Study Guide.

Self-Quiz on Basic Radio Communications

  1. What are two basic types of hand held radios?
  2. What may happen if you begin speaking immediately after you press the transmit button?
  3. What are some strategies to improve communications if signals are weak or broken?
  4. Why is a "death code" used?
  5. Under what section does the communications function occur in the ICS system?
  6. Is a license required to use a specific radio frequency for communications during a mission?
  7. Under what conditions may a person transmit on a radio frequency without an FCC-license?
  8. How often should teams check in with base camp, and why?
  9. What should you do if you permanently lose communication with base camp?
  10. What are two main reasons to avoid unnecessary transmissions on the mission frequency?
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