Homing Technique

When you can hear a beacon but not see it, homing is the systematic way to walk to it. The method is simple: move in the direction where the signal grows.

The method

1. Note the RSSI (see Firmware RSSI Measurement for reading it).
2. Walk a straight line 30 m in one direction.
3. If the signal grows, keep going. If it shrinks, return and try the other direction.
4. At every step, correct course toward the strongest reading.

The walls of the corridor

As the signal grows, small course errors become visible: the RSSI drops when you drift off the line. Homing is walking down a corridor whose walls are made of RSSI. The corridor narrows as you approach.

The multipath trap

Reflections can create false peaks: a rock face can bounce a stronger signal from the wrong direction (see Propagation Modes). The escape:

• When the signal suddenly drops to near nothing, you were homing on a reflection.
• Move laterally 20 m and re-measure; the direct path reappears.
• The beacon’s repeated bursts make this retry cheap: it transmits every interval.

The last 100 meters

In the final stretch the signal saturates and RSSI stops discriminating. Switch to the audio: the tone’s loudness and clarity guide the last few dozen meters, and the whistle protocol (see Whistle Signals) takes over when the beacon is in sight.

Related pages

• Signal Strength Mapping for the map version
• Radio Shadow for the dead zones
• Search Patterns and Procedure for the search side