I'm pasting this into a separate reply since it's fairly lengthy:
Suggested Protocol for Testing of Used Avalanche Beacons
By Jonathan S. Shefftz
Here are some tests, based upon Jeff Lane’s TAR article with my input, plus some additional modifications since then:
1) Perform a check of initial signal acquisition range. This varies enormously among different models, so compare your results to another unit of the same model.
a) Set up your target so that the long axis of its housing is pointing directly at the searcher. BCA DTS & T2 models make poor targets because the transmission antenna is at a 45-degree angle to the housing, so optimal alignment is difficult to establish. Ortovox 3+, S1+, and Zoom+ “Smart Antenna” models also make poor targets since they can switch transmission between the antenna on the long axis versus the short axis. (The DSP Pro and DSP Sport models can also switch, but they display which antenna is transmitting.)
b) Start with your test searching beacon in send mode well outside of its receive range.
c) Then, switch the beacon to search, and walk at a moderate pace toward the target beacon.
d) Note the distance, turn the beacon back to transmit, and repeat the test a couple times.
e) Then repeat the entire test, but with the target beacon at a 90-degree angle to the searcher.
2) Perform a check of transmission range.
a) This is very similar among different models, so just about any other beacon should work as a comparison unit.
b) But once again, the BCA DTS & T2 make for poor comparison models (unless of course that is the unit you’re trying to test), since mimicking the same alignment as another model is difficult.
c) And the Ortovox “Smart Antenna” models are kind of hopeless for this test (even when using them as the baseline to test identical units), since you never know which antenna they’re using to transmit.
d) The test configuration is essentially the same as for initial signal acquisition range, but this time you keep varying the transmission target, and keep the searching beacon constant, so any variation is attributable to different beacons in transmission strength.
3) Inspect the beacon’s casing and harness system for any physical damage, such as cracks or loose switches.
4) Inspect the battery compartment for signs of corrosion or looseness.
5) Inspect all the display components, including making sure the direction arrows function properly when in search mode. For a quick test of a possible problem in this regard:
a) Set up the target beacon and your test beacon so that they are in optimal coupling alignment, i.e., pointing directly at each other. (Note the previous caveats about BCA and certain Ortovox models.)
b) Put them far enough apart so that your test beacon is outside the pinpointing/fine phase, but well within the initial acquisition range.
c) The center directional indicator on the test beacon should display. If not, you have either a broken secondary antenna or some other major problem (consigning the beacon to target-only practice).
6) Ensure the functionality of all buttons and switches. Do they do what they’re supposed to do? If the beacon has an auto-revert function, does it actually revert to send after the specified amount of time and/or lack of activity/motion?
7) Check for frequency drift with another beacon that has such a capability. This is particularly important with older analog beacons, e.g. the F1 Focus, which may drift outside of the international standard for avalanche beacons, 457kHz +/- 80Hz. Unfortunately, you can’t test for frequency drift with the range tests previously described, since different beacons have widely varying abilities to pick up a drifted transmission. Beacons with frequency test functions include:
a) Pieps discontinued DSP Advanced, discontinued DSP (sans nomenclature appendage), and current DSP Pro (but not the current DSP Sport or the discontinued DSP Tour)
b) Ortovox S1 (discontinued), S1+, 3+
c) Barryvox Pulse
And if you’re really into all this, the Pieps tester is unique in displaying just how far off the frequency is from spec (even if it’s within spec), and the S1/S1+ is unique in also testing for transmission “On” time and total “On” + “Off” cycle time.
8) Run through a couple practice searches, looking for errant behaviors. Try it with single burials and with multiple burials; this is particularly important with modern beacons running complex algorithms. This is much involved and open-ended than any of the prior tests, but then again, it is providing you with additional rescue practice!