Avalanche beacon technology has improved significantly in recent years. These improvements, while definitely in your best interest, have left many customers feeling a little overwhelmed. You may have read articles or heard friends mention differences between digital and analog beacons, single antenna and multiple antenna beacons, search ranges, operating frequencies, flux lines, etc. Unless you're a techno-geek, these features are probably a little confusing. We'll try and help you understand avalanche beacon features below, and provide you with the info you'll need to sort through the options. Read on to see what we've got to say about operating frequency, flux line search, digital vs analog, search range, other features, and model specific features

The single most important feature that your avalanche beacon MUST have is the correct signal transmission frequency. All new beacons transmit and search at an operating frequency of 457khz (international standard). Some older beacons used a different frequency, and will not be compatible with any new models. Others, like the Ortovox F2, split the power between two frequencies - resulting in a weaker signal. Make sure that everyone you are venturing into the backcountry with is using a current model, and that they know how to use it.

No matter what type of avalanche beacon you've got, a flux line search is the fastest way to locate a transmitting beacon. Given that fact, flux line signal transmission is an important concept to understand. OK, it is also a pretty difficult concept to understand, so bear with us. The antenna in a transmitting beacon sends out an electromagnetic signal. Because this signal is in the form of an electromagnetic field, it does not simply radiate outward in all directions at equal strength. This signal actually transmits in a "flux line" pattern in all three dimensions (see image).

Beacons in "search" mode receive this signal from the transmitting beacon. The strength of the signal received is dependent on the searcher's location along the flux line of that signal. Signal strength increases along the flux line path, moving toward the transmitting beacon. Beacons that use digital processing to give distance and direction information DO NOT point the user directly at the transmitting beacon. These beacons actually give distance and direction info along the flux line. The search technique that follows increasing signal strength along the flux line is know as the "flux line search"

All avalanche beacons essentially transmit an analog signal via a single antenna. The "analog" distinction refers to a beacon which also uses a single antenna to receive the signal. These beacons usually combine a visual display of signal strength with an audio "beep" which gets louder as the signal strength increases. Signal strength increases when the antenna is aligned with the flux line of the transmitting beacon, and continues to increase as you move closer to the transmitting beacon along this flux line. Some single antenna beacons, such as the Ortovox M2 and the Arva 9000, use digital processing to provide distance and alignment information but are still considered to be "analog" beacons.

Generally, the "digital" distinction refers to a beacon which uses more than one antenna to receive a signal. These beacons use a microprocessor to combine information from multiple antennae, providing direction and distance information (along the flux line) to the transmitting beacon. Digital beacons usually combine a visual distance and directional display with an audio "beep" that increases in frequency as you move closer (along the flux line) to the transmitting beacon.

Most beacon users agree that digital beacons are easier to use, especially for novices. The learning curve is significantly shorter, and for those who don't practice often, search times are much quicker - VERY important in avalanche rescue situations. Given these benefits, digital beacons have been quite a bit more popular in recent years than analog. That said, there are advantages to analog beacons. If you're used to using one or are willing to put plenty of time into practice, search times can be just as fast (or faster). Many experienced users actually find the "real time" audio of an analog beacon more intuitive to use in pinpoint searches as well as multiple burial searches. Also, battery life is significantly longer and, when used properly, search range is longer.

Search range can be very important in large avalanches, or in situations where you haven't seen a slide happen. A large range decreases initial search time by allowing for a wider search strip pattern while trying to find a signal. It is important to understand, though, that the range information provided by the manufacturer isn't always accurate. Range is heavily dependent on battery strength and antenna orientation. Signal strength along the flux line is strongest when the receiving antenna is parallel to the sending antenna. Given these variables, it is best to assume that the range of your beacon is significantly less than the maximum range stated by the manufacturer.

Many avalanche beacons offer a variety of "special features" designed to make the search process easier or quicker. One of the most common special features is the ability to switch between analog and digital modes. The Ortovox X1 begins in analog mode to increase search range, and automatically switches to digital mode when 10 meters away to simplify the pinpoint process. The Barryvox Opto 3000 can be set to switch between analog and digital mode at your desired distance, and has a variety of customizable settings including "real time" audio, directional info, and revert to send mode.

Another common special feature is a "multiple burial" search mode. The new Pieps DSP is the most impressive and easy to use in multiple burial mode, but the Barryvox Otpo 3000 and the BCA tracker DTS both offer a similar feature.

The Ortovox M2 offers a wealth of special features in an analog beacon, and is still considered by many to be the best beacon on the market. This beacon tells the user when the antenna is lined up with the flux line, how strong the signal is, and how close you are(along the flux line) to the transmitting beacon.

Remember, the very best way to insure that your beacon will help locate an avalanche burial quickly is to PRACTICE with it. All the bells and whistles in the world won't help in an emergency situation if you don't know how to use them. Take the time to learn how to use every feature, and practice finding buried beacons with your friends as often as you can. It won't do you any good if you are the only person in your group who is skilled with your beacon - make sure your partners practice too!

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