Morse & light
Light and sound signals always work – without mains power, without a network, without prior knowledge on the receiver's side. What matters is the SOS pattern: three times short, three times long, three times short, pause, repeat.
How to signal
- Torch: short = 1 s, long = 3 s, pause, repeat
- Whistle: 6 blasts per minute = alpine distress signal
- Mirror: flash sunlight towards the aircraft/helicopter
- Rescuers' reply: 3 signals per minute
The Morse alphabet: short, long, rhythm
Morse code knows only two building blocks: a short signal (dot, spoken "dit") and a long signal (dash, spoken "dah"). Every letter is a fixed combination of these. What matters is not the absolute speed but the clean ratio of the lengths to each other – which is why Morse is best learned through sound, not through the written form.
The timing follows fixed units: a dot lasts 1 unit, a dash 3 units. The pause between two signals within a letter is 1 unit, between two letters 3 units and between two words 7 units. Whoever keeps these ratios is clearly understandable even slowly.
- E = · (one "dit") and T = − (one "dah") are the shortest characters – ideal for practising the difference in length.
- A = ·− ("di-dah") and N = −· ("dah-dit") are mirror images – a good pair for training the order.
- SOS = ··· −−− ··· – three times short, three times long, three times short, as one continuous sign without letter pauses. The internationally valid distress signal.
- HELP is spelled out: H = ····, E = ·, L = ·−··, P = ·−−· – that is "···· · ·−·· ·−−·". Between the letters leave the longer pause (3 units) each time.
- For beginners: first learn only E, T, A, N, S, O – with these you can already form SOS and simple words.
- Expert tip: the Swiss alphabet additionally knows Ä = ·−·−, Ö = −−−·, Ü = ··−− and CH = −−−−. The last is the only "letter" made of four dashes and easily confused – when in doubt, write it out (C then H).
Transmitting with light, sound and mirror
Morse can be transmitted on any channel that has two clearly distinguishable states: light on/off, whistle short/long, mirror flash short/long. For distress signals the receiver does not need to know the code – the SOS pattern or the alpine distress signal is enough.
During the day a signal mirror (heliograph) carries furthest: it directs sunlight in a targeted way towards an aircraft, helicopter or distant person. At night the torch or headlamp takes over. Over short distances and in poor visibility the signal whistle is clearly superior to shouting, because it takes less effort and carries further.
- Torch: short = about 1 second on, long = about 3 seconds on. SOS = three short, three long, three short, pause, repeat.
- Signal mirror/heliograph: in sunshine, guide the spot of light over your outstretched hand towards the target; even without code, a repeated flash already acts as a call for help.
- Whistle: carries further than the voice and hardly tires – ideal in fog, darkness or exhaustion.
- Alpine distress signal (SAC): 6 signals per minute (about every 10 seconds a visible or audible sign), then 1 minute pause, repeat. The rescuers' reply is 3 signals per minute.
- For beginners: headlamps often have a flashing/strobe mode – it transmits automatically for hours and is easily recognisable at a distance.
- Expert tip: the traditional alpine distress signal is known to only a few today. In an emergency, rely first on the telephone, the Rega emergency call 1414 or an emergency app – light/sound signals are the fallback level when none of these is available.
Learning Morse: through sound
Anyone who learns Morse by heart from a table fails at listening – the brain translates too slowly. What has proven effective is to learn the rhythm from the start: every letter is a little melody of "di" and "dah".
- Koch method: start at full target speed, but begin with only two characters and expand gradually. This way you learn the sound from the start instead of counting.
- Mnemonics help at the beginning: A "di-dah", T "dah", S "di-di-dit", O "dah-dah-dah".
- For beginners: practise daily for 5–10 minutes with a Morse app that plays the tones – short, regular sessions beat long, rare ones.
- Expert tip: train whole words and acknowledgement signals (e.g. AR = ·−·−· "end of message") as a sound image, not letter by letter.
Good to know
- Rescuers actively search for light signals
- Large ground signs (X or SOS) are visible from the air
- The headlamp flashes for hours in strobe mode