Avalanche transmitter technology has been around since the 1970s with very little core improvement other than cost reduction.
The main change in recent years has been the rise of digital receivers with little arrows and LED read- outs which make operation of these systems more user-friendly for those who rarely use them.
Though many of the receivers are now digital, the signals are still analog, and they all operate on the same frequency (457 Khz) which means any avalanche transmitter can work with any avalanche receiver, regardless of manufacturer.
The 457 Khz frequency is an international standard that was put aside for rescue devices in 1968. This relatively low frequency (just below the AM dial on a radio) was chosen for rescue work because the signal is relatively unobstructed by walls, concrete, snow, ground, and human bodies, etc.
The new Bellman and Flint terrier telemetry rig, which uses an avalanche receiver and 457 Khz transmitter is going to sell for over $500 -- twice the cost of the new Deben system which, in turn, is twice the cost of the old Deben system.
Bellman and Flint seem to be using an unmodified Pieps DSP (digital signal processing) box as their locator. These locators are made in Austria, and sell for about $350 retail.
The chief advantage of the Pieps DSP box for avalanche rescue is that it can locate multiple burials at once -- a common problem with avalanches, but a rare problem with terriers underground.
An alternative to the $350 Pieps receiver shown above is the 457 Opti 4 Pieps receiver shown below, which costs just $160, and seems to do everything we actually need in the dog world -- and a little bit more. I am unclear as to why this receiver was not selected by Bellman and Flint, or why it should not be selected by others now.
The Pieps 457 Opti 4 has a battery reserve indicator, optical display with 4 LED's, a range of 60 to 70 meters (180 to 200 feet), precision localization to approximately 30 cm (11 inches), volume control with distance marking, built-in speaker, an earphone jack, and a 5-Year Warranty. Like all avalanche locators it will pick up a 457 Khz transmitter signal.
What about the collar?
Several companies make 457 Khz transmitters, and one of these was apparently modified into a collar-locator by Bellman and Flint. A picture of the Bellman and Flint collar is not shown on their web site, but they admit it is bigger than the transmitter used by Deben.
One 457 Khz avalanche transmitter already being used for dogs is the Ortovox Military D1 Transmitter, which has a 30 meter range, and is pictured below. This transmitter comes with a small slit in the back through which to thread a dog collar. It is for sale at Backcountry.com for $85.
Pieps also sells a small 457 Khz transmitter. It's called a Pieps Powder Peep Beacon and is sold separately for about $75. This may be what Bellman and Flint have modified with a magnetic switch (like Merlin hawk locators have), but it's hard to know without seeing a collar.
What about electrical interference from overhead power lines? The Bellman and Flint site does not say their collars are immune to power line interference, but all the avalanche locators seem to be somewhat resistant.
That said, as one avalanche box manufacturer notes, "Irregular readings can be caused by . . . power lines, electrical storms, and electrical generating equipment." Perhaps this is why no claims of resistance to electrical interference are mentioned on the Bellman and Flint web site.
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