Communications enroute, around camp, on the waterand on the trail, are important. Today's cell phones work pretty well in populated areas and even along most highways. Sometimes they even work surprisingly well in remote locations, but hand-held CB, FRS or GMRS radios are a good addition for camping, hiking, and OHV trips, especially if you're headed off the beaten path and out of cell phone coverage. The addition of an external cell phone antenna may improve reception and transmission, but make sure your phone is compatible with the antenna connector. I have an external cell phone antenna on my motorhome that worked well with previous phones but my current model doesn't have an external antenna connector. HAM radios are bit more expensive and require training and licensing but have a much greater range than FRS and GMRS radios. Be aware that virtually all radio communications are "line-of-sight". If you're in one valley and the person you're trying to communicate is over the hill in the next one, you probably aren't going to have much luck. Short wave (HAM) radios can sometimes take advantage of something called "skip", where signals bounce off layers in the upper atmosphere and can reach over the horizon, but for most applications you need a pretty clear path between transmitter and receiver for reliable communications. Of course, these days, cell phones are pretty ubiquitous and can provide communication between vehicles in a convoy and between camp sites. You might even be able to make emergency calls out on the trail, but remember, cell phones depend on being within range of a cell tower. While cell towers cover most cities and even most regularly used highways, you may find coverage lacking in remote mountain and desert areas where you go camping, riding, or hiking. Marine environments use special radio frequencies and special radios tuned to those frequencies. If you do any off-short boating you are going to want good two-way marine radio communication. Most marine radios include features that will aid rescuers in locating your boat in an emergency. You may use CB, HAM, and FRS/GMRS radios for short range communications between boats in a group like you would among campers.
Not all communications have to be two-way communications. A good NOAA weather radio can be an extremely valuable addition to your camping communications gear. These specialized radios provide continuous local weather forecasts and alerts. Any good radio can usually provide news, traffic, and weather updates. Even a good am/fm portable radio can normally bring you news and weather alerts. Sometimes the radio signals will bounce of parts of the atmosphere but they are usually "line of sight" and mountains or other obstacles will sometimes block reception. Modern satellite radio systems take advantage of transmitters on orbiting satellites so they usually work just about anywhere above ground.
I recently saw an ad for a multi-band radio that include VHF, CB, Ham, AM and FM all in one unit. Such a radio would certainly provide the most flexibility for remote communications, but they are a bit pricey: around $500! Nice thing to put on the wish list.
On the road. CB radios are still used by over-the-road truckers and can be easily added to just about any vehicle to provide convenient communications between vehicles enroute. Hand held versions avoid the need for permanent antennas and wiring to a 12-volt power source. By the way, RVs, because of their fiberglass bodies, may require a special No Ground Plane antenna. The range of CB radios is limited to a few miles, but should be more than adequate for most RV "convoys". CBs have up to 40 different channels. Some channels have been designated for specific purposes. Channel 9 is reserved for emergency communications. Channel 19 is the channel usually used by over-the-road truckers and an excellent source of traffic and road conditions on most major highways. Truckrs sometimes use Channel 17 on North-South Highways and Channel 19 on East-West routes. Channel 19 is dead center of the CB band and is where antennas are frequently most efficient. Channel 13 is the "RV" channel, and good place to listen for other RVers. You can choose any of the other channels for more personal communications for your group. It may take some searching to find an unused or lightly used channel. Hand held FRS or GMRS walkie-talkies are good for in camp and trail communications. FRS (Family Radio Service) is what is used by inexpensive and toy walkie talkies and has a more limited power and range than GMRS (General Mobile Radio Service), which uses more power and has a longer range -- but you have to have license to use GMRS. FRS and CB do not require a license. For added convenience on the trail, a headset provide hands-free operation. Though somewhat pricey, "Sidewinder" brand radios are about the most convenient way to communicate with fellow riders on the trial. These attach to your helmet and can be voice activated. Be careful using voice activated units. You're likely to broadcast some unintentional expletives when something goes wrong or surprises you! I've had good success with ordinary walkie-talkie type FRS radios by tucking them in my Cambelbak and using a pu st-to-talk microphone and earphones under my helmet. Again, the range is not great, but is usually more than adequate for keeping a group together on the trail and sometimes can even reach back to base camp so it can be useful to have someone monitoring your frequency back there in case of an emergency. We've even used them between groups out on the trails to coordinate emergency services when one of the riders was injured.
Other forms of communication can also be useful. I may owe my life to a little-known trucker's signal. I observed a truck driver speeding down the opposite side of the freeway toward me, flashing his lights 3 times over and over and giving three blasts on his air horn as he passed by. Within a few minutes I encountered a wrong-way driver coming down my side of the freeway like a bat out of hell! The trucker's warning had put me on high alert so I detected the oncoming driver approaching in my lane in time to move over out of his way. I admire that truck driver for his thoughtful efforts to warn people of the impending danger. I may even owe him my life! This was in the days before cell phones. I pulled off at the next exit and called the State Police, whose tired response was "Where is he now?" Obviously I wasn't the first one to report the wrong way driver and he had been southbound in the northbound lanes for at least 25 or 30 miles. Speaking of wrong way drivers, a Highway Patrol friend of mine offered the following advice: Do not drive in the fast lane of the freeway at night, especially on holidays when alcohol consumption is high, like on New Year's Eve. If you get a wrong way driver (like the one I encountered), he's probably going to be staying to his right, thinking he is being extra safe. That puts him in the fast lane when he's on the wrong side of the freeway! My friend says this tidbit was passed on to him by his trainer early in his career, and just minutes later after moving out of the fast lane, he encountered a wrong way driver right where his trainer said he'd be: coming down the fast lane. When they finally apprehended the guy miles later he insisted the cops had lifted his car over the concrete center divider so it would look like he was driving on the wrong side. I know cops are tough, but not THAT tough!
Some classes of radio communication require special licensing by the FCC. CB radios used to require a license but no longer do. FRS radios (Family Radio Service) do not require a special license. Range is about 2 miles. GMRS (General Mobile Radio Service) offers greater range on some channels but does require an FCC license for the higher powered channels. A single GMRS license covers the holder and his/her immediate family for personal or business purposes. Last time I checked the GMRS license cost $85.00 and was good for 5 years. Some GMRS channels are shared with the FRS service and can be used without a license if you don't exceed the legal transmission power (many GMRS radios have "power save" options that operate at the FRS power, using them at higher power requires a GMRS license). For long range communications you may need an amateur radio (HAM radio) and license. HAM radios can sometimes take advantage of repeaters -- automated stations that re-transmit your signal, to extend the range. You can often get HAM radios classes free from local HAM clubs or educational institutions. The license itself costs $14.00 and is good for 10 years before they have to be renewed. Hand-held radios can be purchased for as little as $45 but a good "base station" and antenna setup can cost hundreds of dollars. Hand helds or mobile radios will be the most useful for camping and caravaning.
Hand signals are useful on the trail. Ordinary driver's hand signals communicate intentions when turning and stopping and can be very useful in keeping everyone in a group on the right track. Left arm extended straight out from the shoulder: left turn. Left arm held at the square: right turn. Left arm held down: stop. Left arm waving as if patting toward the ground: slow down. Another helpful signal aids safety when approaching riders coming from the other direction. Hold up your free hand displaying the number of vehicles behind you in your group. If there are more than 5, hold up an open hand. Raise a closed fist, with the fingers facing out, if you are the last rider. This tells oncoming traffic how many riders to expect. Don't display your fist with the back of the hand out as that can be interpreted as an aggressive gesture. Thumbs up and thumbs down have specific meanings so avoid using them in the ordinary "OK/Not OK" sense. Thumbs up means a crashed rider is back up. Thumbs down means he is down and can't get up. A simple wave of one hand high over head, like waving "hello", is usually used to indicate "OK". Low waving of one hand about knee level indicates "not OK". Avoid low waving of both hands as it is often misinterpreted by baseball fans as "SAFE".
Hand signals can be helpful in camp too, especially when backing into a tight spot. A closed hand with a thumb extended like you were hitchhiking can be used to show the driver which way the back end of the RV needs to go. A closed fist means stop. Slapping the side of the RV means STOP NOW! You can indicate the driver needs to keep backing up by waving you hand in a "come hither" manner. Then quickly raise your and and close your fist when they should stop. Another useful gesture is to indicate the remaining distance by holding your hands apart facing each other and bringing them closer together as the gap closes. It helps the driver judge how much further he/she needs to go. Hand signals avoid the problems of trying to yell commands and disturbing fellow campers. Two-way radios will let you carry on necessary conversation without yelling but can still be surprisingly loud in a quiet campground.
Though not commonly used any more, flashing Morse code and semaphores (flags) CAN be used to communicate between camps, on the water, and on the trail. There are marine flags with specific meanings you should be aware of when boating. They will alert you to water skiers in the water, disabled craft, medical emergencies, out of fuel, and dangerous conditions. One Morse code signal that IS still frequently used is "S O S", an internationally recognized plea for help. This consists of three short flashes, three long flashes, and three short long flashes (... --- ...) . In popular usage, SOS became associated with such phrases as "save our ship", "save our souls" and "send out succour". These may be regarded as useful mnemonics, but SOS is not an abbreviation, acronym or initialism. According to the Oxford English Dictionary (2nd ed.), the letters were chosen merely because they are easily transmitted and recognized in Morse code. When transmitted in Morse code they are often run together (...---...) instead of being sent as separate letters. Morse code can easily be sent as flashes of light or as sounds. You can even send Morse code by beating on a hollow log or banging two rocks together -- three quick hits, three slow hits, three quick hits, spells S O S. An ordinary whistle is a good emergency communication device. You won't ruin your voice yelling and it carries well to alert rescuers to your location. You can whistle "SOS" or just give 3 loud, evenly spaced whistles periodically. The three blasts and rhythmic timing helps distinguish your signal from bird calls or other natural sounds like wind or creaking trees.
Parking an RV sometimes requires two people: one to drive and one to watch where the vehicle is backing, especially when backing into a confined space. See the previous paragraph "Hand signals can be helful in camp too". Two way radios are very helpful here although well understood hand signals can often suffice. DON'T just try yelling! It will annoy your fellow campers and will probably not do very much good anyway. A good "emergency stop" signal is to slap the side of the RV hard. The driver will be able hear it and can stop and discuss the situation before any damage occurs.
Stop and talk. Whenever you are traveling in a group -- in vehicles, on OHVs or just hiking -- it is a good idea to stop and talk face to face now and then. You can check the status of fellow travelers or riders, alert associates to where you're going next, and adjust routes as needed when special circumstances arise. It is always better to catch any emerging medical or mechanical problems in the group as soon as possible. When on the trail you can check everyone's ability to identify the way back to camp and help them learn landmarks and trail tips that can help them find their way back if they get separated from the group. It is also a good idea to stop and talk periodically when you're in a RV or other vehicular convoy. Regular rest stops keep drivers fresher and more alert and stops give you a chance to socialize with members of your group and discuss any special needs or wants and plan additional food, fuel, and recreation stops and let the group address the concerns of anyone who is uncomfortable with the pace or the route.
Boats have their own visual and audio signals that you should be familiar with if you are out on the water. Navigation lights can help you determine which way a boat is moving relative to your position. Boats have red lights on the port (left) side and green lights on the starboard (right side) and a white light visible from the rear. Sailboats might also display white light visible from the front and higher than the navigation lights to indicate they are under auxiliary (motor) power at night. A white light high up and visible all round (360 degrees) at night indicates a boat is at anchor. Boats use audio signals (horns, whistles) to signal how they intend to pass each other. They use short and long blasts, with a short blast being about 1 second long and long blast being 4-6 seconds long. One short blast means I want to pass you on my port (left) side. Two short blasts mean I want to pass you on my starboard (right) side. Three short blast means I am backing up. Five short blasts means danger or you disagree with the other boater's intentions. One long blast is used in low visibility, like fog or coming around a blind corner. Sailboats should use one long blast followed by two short blasts in limited visibility. Since sailboats maneuver and respond differently than power boats it is useful to know if the boat approaching is a sailboat so you can be better prepared and allow greater space or reaction time. A sailboat operating under auxiliary power is considered to be a power boat and must obey all the rules for power boats. Boats also use flags. Some of the most common are the Alpha Flag (blue and white) for diver down deep in the water, Whiskey Flag (blue with white and red concentric squares) for medical emergency and need help, an orange flag for water skier down, and a distress flag (orange with a black square and black circle). The Alpha and Whiskey flags each represent letters in the alphabet, A and W respectively. Boats may also use "day shapes", recognizable shapes that are displayed to indicated a sailboat under power (an inverted black cone) or a boat at anchor (black ball).
Talk it up!