Mountain Safety
August 11th, 2019
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Avalanche Transceiver 101

While modern avalanche transceivers are bursting with great features, not all are created equal. With small technical differences between models, it can be difficult to know which is the right choice for you. To help you choose, here are some key features of today’s avalanche transceivers, and how they work.

Digital vs. Analog

Every avalanche transceiver in production today is digital, but some also offer analog functionality. Here’s the difference between the two: analog transceivers relay a signal as a sound that increases in volume the closer you get to a burial; digital transceivers use computing power to analyze a signal and translate it into clear directions for the user. Digital functionality is much easier to use, and faster as a result. While old-school analog transceivers do have a few minor advantages such as longer range and better battery life, they are otherwise decisively inferior to digital transceivers.

However, a couple of advanced digital transceivers—like the Mammut Barryvox S for example—offer the benefits of both, by allowing expert users to switch to an analog mode as needed in rare circumstances. However, for the vast majority of avalanche transceiver use, digital is all you’ll need.

Number of Antennas

All modern transceivers feature three antennas. If you’re shopping for a new transceiver and see one with fewer than three antennas, set it down! Way back when only analog transceivers were available, they all had just one antenna. Then, with digital technology, two-antenna transceivers became the standard for some time.

However, we live in a three-dimensional world. Hence, today’s three-antenna transceivers—one for each axis. The X- and Y-axis antennas do the bulk of the work in a coarse search, gathering distance and direction data. The third antenna (Z-axis) comes into play at very close range, for a more accurate fine search—especially in the case of a deep burial.

Range

Range is the maximum distance a transceiver can detect and interpret a signal from another transceiver. Essentially, the bigger the range, the faster your signal search can be. Current transceivers can process a signal at a maximum range of between 40m and 70m, depending on the model.

Longer range permits a searcher to make a wider signal search grid. That means less physical distance to cover. A searcher with a more efficient search pattern may also find a signal faster and be less tired when it becomes time to excavate the victim.

 

Avalanche Transceiver 101

Mark/Flag Function and Multiple Burials

Modern transceivers all indicate in some way if there is more than one transceiver signal found—a multiple burial scenario. And most—but not all—feature a marking (or flagging) function, which allows the transceiver in Search Mode to ignore a nearby transceiver signal. But why would you want to do that?

Here’s a scenario:
You’ve got two or more friends buried in an avalanche. You’ve just located Victim #1 with a fine transceiver search, followed by a positive probe strike on the victim under the surface. While other members of the rescue group set to work extracting Victim #1, you can now use the mark/flag feature on your transceiver to suppress or effectively ignore Victim #1’s transceiver signal. This allows you to continue searching for other victims immediately, without the confusion of being inadvertently directed back toward Victim #1’s location.

Mark/flag is a critical time-saving feature for multiple burial incidents. You should seriously reconsider buying or owning a transceiver without a mark or flag feature.

 

Barryvox S Avalanche Transceiver

Auto-Revert-to-Send

Here’s how the auto-revert-to-send feature works. Let’s say there’s an avalanche and someone is buried. You organize a search. The rescuers all switch their transceivers to Search Mode and start searching the debris. Then BAM—a second avalanche descends on the rescuers, and more people are buried. Well, if the rescuers’ transceivers are in Search Mode (receiving instead of transmitting), then there’s no hope of locating them under the snow, right? Well, with an auto-revert-to-send function, if a transceiver in Search Mode does not detect movement for a pre-determined period of time (usually a few minutes), it will alert the user and automatically switch back to Send Mode so that it may be located.

Group/Partner Check

A Group or Partner Check function simplifies the matter of performing the daily trailhead transceiver check for each member of your party. The process is improved in two ways.

First, party members’ transceivers can be checked at a short distance of around 1 meter. This makes it much easier to quickly confirm that everyone in the group is sending, without having to spread way out. During each check, the transmission frequency, duration and cycle of each transceiver are tested for faulty performance.

Second, a transceiver in Group Check Mode will automatically revert to Send Mode after a few minutes. This eliminates a common error in which the user forgets to switch over manually after performing the trailhead check.

Upgradeable Firmware

The ability to update the software on your transceiver means that you can always have the most up-to-date performance without having to buy new hardware regularly. The most modern transceivers use Bluetooth smartphone connectivity to perform firmware upgrades. Others use computer software which installs updates through a USB cable. But most transceivers must still be brought into a local shop or sent away to the manufacturer.

 

PIEPS Pro BT PIEPS Powder BT Featured


Transceiver Q&A

Q: Can all makes and models of transceiver find one another?

A: Let’s say your friend has a BCA, but you’re looking at an Ortovox. Will you be able to find each other? You bet. All transceivers utilize the same 457kHz frequency so they can find one another, regardless of brand.

Q: Can I put my transceiver in a pocket instead of the chest harness?

A: Transceiver manufacturers recommend wearing your transceiver in the harness that comes with it. However, some advanced users are known to clip theirs into a zippered pocket for quick access.

Q: Will my transceiver work if my cell phone is on?

A: Manufacturers recommend that you put your phone into airplane mode. All electronics should be stored at least 30 cm away from your transceiver. Electronic noise from other devices can interfere with the search function of your transceiver.

 

Important Tip!

Don’t forget to remove the batteries from your transceiver at the end of the season! Battery corrosion can ruin your transceiver and void your warranty.

 

– Jessica