FAQ

tBeacon was originally designed to aid in locating lost RC aircraft (airplanes, helis, multicopter), but also successfully used to locate a fallen rocket, balloons, as an anti-thief system for bicycles and motorcycles, and even to locate lost cows :) tBeacon is superior to its competitors cause it's independent of cell coverage, has low weight and size. It offers several modes of operations: reporting GPS coordinates, radio direction finding, and also unique Proximity mode, which is essentially radio ​foxhunting on steroids. To aid the searching in close proximity the beacon is equipped with a loud buzzer and bright LED.

There are two options to get the beacon: to DIY a simplified version, or to buy. DIY question is next. If you want to buy you can do it here on the site or in stores. Buying on the website is simple: you pay via PayPal (shipping address is filled automatically), and after some time get it via post.

Sorry, not anymore :(

In order to be able to locate the beacon, you’ll need a UHF radio transceiver, which is able to transmit a calling tone of 1750Hz (tone burst). Most people choose Baofeng UV-5R. If you plan to change the settings and update the firmware, you will need a UART adapter (for example: like this). Except for tBeacon Black - it has a micro USB connector onboard. Also, there are adapters for some autopilots/drones available for purchase.

413MHz - 480MHz. This includes all of the allowed ranges: LPD, PMR, FRS / GMRS.

All beacon versions, except tBeacon Black, are able to "eavesdrop" data from common GPS receivers and autopilots telemetry. The optimal solution is to connect the beacon to the onboard GPS, it saves weight and extends the beacon operation time. But it is possible to use a dedicated GPS receiver exclusively for the needs of the beacon. However, in this case, it is recommended to consider buying a tBeacon Black - it has a GPS receiver onboard and is more autonomous in terms of connections.

Virtually all of them :) The beacon can understand GPS NMEA and UBX protocols, it covers all hobbyist GPS receivers. Also, telemetry protocols of MAVLINK, NAZA, and ET OpenTelemetry are supported.
There are wiring diagrams for some common cases.

The beacon is activated when it hears a specific audio tone of 1750Hz in the air. This tone is called Tone Burst and is used to select an amateur radio repeater. By default, the beacon listens for a call with an interval of 3 seconds. That is, to guarantee the beacon is activated, you need to provide a signal on the air for a little more than 3 seconds.
The period can be decreased or increased and, respectively, increase or decrease the power consumption of the beacon.

Yes, you can use CTCSS subtone or generate a tone of the needed frequency with your smartphone, etc. 

A beacon being powered on emits welcome beeps and reports the battery voltage on the programmed frequency (433.075MHz by default). Then the beacon goes into standby mode: green LED flashes every second, and red LED flashes in moments of any activity. If you can't hear anything in the air, you should check that the beacon and the radio is tuned to the same frequency (it is recorded in Hertz in the configurator, do not miss zeros), and make sure that CTCSS/DCS is off.
If you have a Baofeng UV-5R radio and the beacon does not respond to the call, try to press the PTT + A/B (not BAND: there is an error in the radio's manual).
If you feel that Baofeng UV-5R "swallows" the beginning of the transmission, you need to set STE and RP-STE to OFF in the radio's settings.

It’s exactly as accurate as their source.
It is possible that during the crash the GPS antenna becomes turned upside down or shaded by something. In that case, the accuracy of the coordinates could decrease, but the deviation could hardly exceed 10 meters.
Another point to be aware of. The beacon reads the coordinates not continuously, but at a specified interval, which by default is 10 seconds. I.e. there could be a situation when the beacon read coordinates in flight, and then after 9 seconds the aircraft could hit the ground and become de-energized along with GPS receiver. In this case, the beacon will remember the last position (in the air) and the crash site will be spaced from the reported coordinates for a distance determined by the speed of the aircraft. For fast planes, it can be critical (at a speed of 100km/h in 9 seconds, the plane can fly about 250 meters). In this case, it is recommended to reduce the interval of GPS reading.

First, you need to determine the search area. If you are in the lowlands, it is better to move as high as possible and try to call the beacon. If the beacon has replied, then that's half the battle, enter the coordinates into your favorite navigation app and have a nice journey to the crash site :)
If there is no answer, then either the beacon can not receive our signal, or (which is more likely) we can not receive the beacon signal. In this case, it is necessary to move higher, or closer to the proposed crash site or simply change your location at random. Ultimately, you should hear the voice of the beacon and receive the coordinates.
If for some reason there are no valid coordinates, then the beacon can be found in a similar way used in ARDF or “radio foxhunting”. The three beeps emitted by the beacon have different power: the first is the most powerful, the second is weaker and the third is quite weak. Thus, by shielding the transceiver by your body or other materials you can determine the direction to the most powerful (clear) signal. Taking a few bearings from different points, one can draw them on the map and found the crash site at the point of intersection. Or a simple way: go the direction of the stronger signal. You may have more to stray, but on the other side, you do not need a map and a compass.

Connecting to Phantom's older that Phantom 3 is similar to other Naza’s. For a convenient connection, you can solder or buy an adapter. You can connect the beacon to Phantom 3 using two equal way: to solder some wires directly to the P3 mainboard or to buy an adapter.
There is no adapter for Phantom 4, but the beacon can be soldered to the mainboard or used autonomously. The same story is with Mavic. Another possible solution is to use tBeacon Black, which has a GPS receiver onboard, but integrating tBeacon Amber into the drone case is still the recommended way.

All of the parameters of interaction with autopilot/GPS are determined automagically.

In case both frequencies are close to each other there will be interferences, BUT...
First, you can set any UHF frequency you like on the beacon, given that it is supported by your radio transceiver and is legal in your country.
Second, and the best: the beacon will not transmit anything on its own. It will transmit only when activated by a call or by a timer.

If you have a direct line of sight(LOS), good antennas, and no interference, the range is not limited to common sense, it is tens of kilometers.
In practice, of course, things are not so easy, and it depends on many factors, one of the most important is the presence/absence of LOS. However, I was able to activate the beacon in the center of a big city, without direct LOS, at a distance of 3 km. And this is with a plain “rubber ducky” antenna and even not leaving the car. Although, of course, at the limit of recognizability. The theoretical range of radio communication under ideal conditions when the beacon is on the ground, and the radio in the hands of an adult is about 4km.

With the default settings and the default battery, the beacon can last on standby for about 6-7 days. With due skills and some compromises, it is possible to increase it to a month or more. On the other hand, it can be configured so that will hardly last for one day :)
And of course, the more capacious battery is used, the longer it lasts. And remember - standby time reduces with every activation.

For two reasons. The first is the lack of flash memory in the microcontroller: all feasible features simply do not fit.
The second is the low noise immunity of DTMF. In noisy receiving conditions where a person can still easily recognize the voice among the noise, DTMF has failed miserably.
Weighing all the "pros" and "cons", I decided to remove DTMF in favor of more useful features.

Any 1S LiPo/LiIon cell will suit. For example, 200-300mah 1S LiPo for micro RC helis will perfectly suit. eBay, aliexpress or banggood is the popular source of such things.

Starting from firmware 0.58 you have to flash the bootloader manually: download this file, unzip it to any folder and run optiboot.bat to flash the bootloader using USBASP.