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Distances, Directions, and Sounds

Digital avalanche transceivers (beacons) display the distance and direction to a buried avalanche victim. They also output audio tones to aid in the search. Analog transceivers, and transceivers with only one antenna, provide a subset of this information.

Audible Indication

When searching with a old-school analog beacon, the only indication you had that you were getting closer to the transmitting beacon was an increase in volume. The pitch and cadence (i.e., the rhythm) remained constant. You were simply listening to the "beep" that was being transmitted by the buried transceiver. Because it is difficult for humans to identify subtle changes in volume, analog transceivers allowed you to turn down the transceiver's sensitivity.

Digital beacons changed all that. Rather than broadcast the received beep through the speaker, they generate an audible tone based on the strength of the signal. Most (maybe all) digital transceivers increase the cadence of the tone (i.e., beeping more frequently as you near the victim). Many digital beacons also increase the pitch of the tone. The combination of increased cadence and pitch is easily recognized by humans.

The Mammut Barryvox S provide the option of hearing a digital signal or an analog signal (by broadcasting the analog tone). The ability to hear analog audio is helpful when determining the level of background interference, listening for faint transmissions, and resolving burials where multiple transmitters are close to each other.

A few transceivers, including the Mammut Barryvox and Mammut Barryvox S, change the cadence of the beep during coarse search when you are not aligned with a flux line (i.e., when you should change directions slightly).

The Ortovox Diract Voice transceiver can speak in nine different languages.

Directional Tones

The Mammut Barryvox and Mammut Barryvox S include a feature called "acoustic search guidance" (Mammut used to call this "directional tones)." When enabled, the audio tone changes when the direction indicator changes. This reduces the need for you to stare at the direction indicator as you work your way toward your buried partner during the coarse search.

Distance Indicators

Most old-school single antenna transceivers indicated the distance to the victim using either a series of lights (e.g., green, yellow, and red). All multiple-antenna digital beacons display the estimated distance in meters.

Transceivers display a minimum distance of somewhere between 0.1 meter and 0.3 meter. The smaller minimums are only significant when you are searching for a transmitter that is buried under less than one foot of snow (as might be the case when practicing).

The distance that is displayed is an estimate of the distance along the flux line rather than the actual distance directly to the victim. The range charts and distances mentioned on BeaconReviews.com are the actual measured distances.

Direction Indicators

Transceivers with more than one antenna display a "direction indicator" that aligns the searching transceiver with the flux lines that are being broadcast by the victim's transceiver. Single-antenna beacons cannot display a direction indicator.

On some beacons the direction is displayed as an arrow whereas other beacons use five lights, three lights, or a grid (the Ortovox S1). The Barryvox S direction indicator is unique, because it displays an arrow that curves to show you your route along the flux line. The Ortovox Diract and Ortovox Diract Voice have "floating" arrows that are similar to the needle on a compass and can point behind you if you are moving away from the victim.

All of the direction indicators are a little inaccurate when they are relatively far from the victim. This causes the direction indicator to jump around. You should average the direction as you advance toward the victim. For example, if the direction indicator jumps between straight-ahead and hard-right, you should average these and head gently right.

When the signal is first received, it is just as likely that the indicator will point you 180-degrees from victim as toward him. You should watch the distance indicator to make sure it is decreasing as you follow the direction indicator. If the numbers are increasing (i.e., you are moving away from the victim), you should turn 180-degrees.

Disappearing Direction Indicators

The direction indicators on most digital transceivers disappears when you get close to the transmitting beacon. That's a good thing, because the indicators get confused when you get very close to the victim—it's analogous to following a compass needle when you are standing directly on the North Pole. The disappearing direction indicator forces you to focus on the distance indicator during the fine search.

If your transceiver does not turn off the direction indicator when you're close to the victim, ignore the direction indicator when you are within a meter or two and focus on the distance indicator.

A row titled "Direction indicator disappears" in the Searching section of the comparison table shows the distance when the indicator disappears. A few transceivers allow you to select this distance via a setting. For example, the Mammut Pulse allows you to select either 3 meters or 0 meters.

 

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