A whistle is a personal short-range signal, carrying about 500 m between sentries, patrols and posts, and a bell or gong is a fixed signal that calls the whole settlement to one place. Keep each to four or five counted patterns that never repeat another instrument’s meaning, and never use a closed fuel container or gas cylinder as a gong.
Part of Signal Systems and Communication
Whistles and bells are the small, cheap members of the audio family: a whistle for a person on the move and a bell for a fixed alarm that the settlement can hear.
Whistles Are For People, Bells Are For Places
A whistle makes a high sharp note that carries clearly over short distances and is easy to localise, but loses energy fast. The parent article puts whistles at the scale of posts within 500 m, and advises no more than four or five signals because complexity causes errors under stress. A bell or gong has a loud, sharp-onset sound that cuts through background noise; it is fixed to a post or building and is rung by whoever reaches it first.
What You Need
- A metal or plastic whistle for each sentry and patrol member, on a cord worn round the neck.
- A bell, a hanging steel plate or a section of rail hung from a sturdy frame at the centre of the settlement.
- A striker, hard enough to give a clear note and light enough to swing quickly.
- A bell pull or rope if the ringer stands a distance away.
- Spare whistles. They get lost, frozen and crushed.
Method: Assigning Signals
Step 1: Fix the whistle code by count, not by length. One blast, two blasts, three blasts. A long blast and a short blast are easily confused when the sentry is breathing hard.
Step 2: Give no pattern two meanings. Watch and Patrol Scheduling gives different whistle meanings for posts (one long attention, two short acknowledged, three rapid emergency) and patrols (one stop, two come to me, three danger), so the same two blasts mean “acknowledged” at one end of a chain and “come to me” at another. Pick one table for every whistle in the settlement and pin it up.
Step 3: Hang the bell where everyone can hear it. Test it from the farthest house, with doors closed.
Step 4: Ring in counts with clear gaps, such as five strokes, a pause, five strokes, so a person arriving late can tell the pattern from the middle.
Step 5: Check and replace. A whistle with a lost pea or a crack gives no note; check every one monthly.
Choosing The Gong
- Steel plate or rail. Hang it from two cords so it can ring freely; strike it with a hard rod.
- Church-type bell. Loud and carries far, but heavy to hang and a skilled casting; keep if one exists.
- Not a closed container. Do not use a gas cylinder, fuel drum or any closed vessel that has held fuel, because a spark from the striker can ignite residual vapour and a cylinder under pressure can fail.
Common Mistakes
- Dozens of whistle signals. The parent article says four or five at most.
- Metal whistle on bare lips in frost. In hard frost bare metal can stick to the lips (a widely known hazard I am recalling); use a plastic whistle or a cloth between.
- A bell too close to a bedroom. The ringer wakes the house and deafens a sleeper.
- Believing the whistle is silent. At night it carries to every ear within a few hundred metres.
Safety
Fuel containers and cold metal
A struck fuel or gas container can ignite its own vapour; use only a plate, rail or purpose-made bell as a gong. Do not hang a heavy bell over a doorway or path where it could fall on someone.
What’s Next
- Learn next: Code Systems — one table for every channel
- Combine with: Audio Signals — whistle use between posts and patrols