Beacon

A Beacon is a late-game utility building that transmits the effects of modules to nearby machines. Beacons do not apply their module effects to themselves, and they only affect buildings that have module slots. When placed near compatible machines, a beacon multiplies the stats of the modules installed in it by a transmission strength and applies that modified bonus (or penalty) to each affected machine. Beacons are commonly used to concentrate speed and/or efficiency bonuses across many machines without having to insert as many modules directly into each machine, enabling denser, higher-throughput factory designs.

The strength of a beacon’s influence is determined by its distribution efficiency and by the number of beacons affecting the same target. For normal-quality beacons the distribution efficiency is 1.5, and the per-beacon transmission strength for a machine affected by n beacons is (distribution efficiency) ÷ sqrt(n). This yields a combined effect that scales with 1.5 × sqrt(n) for n normal beacons, which produces diminishing returns as additional beacons are added. Only speed and efficiency modules can be placed into beacons; productivity and quality modules have no effect through beacons. All module effects (beneficial and adverse) are multiplied by the transmission strength.

Beacon placement and array design are central to efficient use. A beacon’s footprint is 9×9 tiles of influence, and the maximum number of beacons that can simultaneously affect a single building depends on that building’s size: 12 beacons for 2×2–4×4 buildings (≈3.46× single beacon effect), 16 for 5×5–7×7 buildings (≈4×), and 20 for 8×8–10×10 buildings (≈4.47×). Practical layouts generally favor linear or tiled beacon arrays rather than surrounding single buildings with the theoretical maximum number of beacons, because beacons are expensive, consume substantial power (480 kW each), and complicate logistics.

Well-designed beacon arrays greatly reduce the number of beacons required per building when boosting many identical machines. A common pattern is a production row flanked by one or two rows of beacons; for example, a row of 3×3 machines between two beacon rows typically places each machine in range of eight beacons while using far fewer total beacons than isolating each machine. Multi-row arrays allow internal beacons to be shared by adjacent production rows; for r rows of equal length c (3×3 machines), the beacon count is B(r,c) = (r + 1)(c + 3). Optimal arrays for 3×3 structures satisfy c = 3r and minimize beacons per structure as the array grows. For large arrays the average beacons per building tends toward 1, making large tiled arrays the most beacon-efficient arrangement.

Practical usage notes and tips:

• Use beacons where many compatible machines are packed densely or where a single machine must be driven to extreme speeds (e.g., limited-space mining drills on rich small patches). Beacons can amplify a machine’s speed far beyond what modules in the machine alone can achieve.
• Do not use beacons for machines that operate infrequently unless you can power-gate them; beacons consume power continuously even when the target machines are idle.
• Surrounding machines with beacons is less efficient than surrounding beacons around rows of machines; row and multi-row arrays drastically reduce beacons required per building and simplify routing.
• Pay attention to alignment. For rows of machines, offsets of one tile can increase the number of beacons covering each machine (e.g., shifting machines relative to beacon rows can increase coverage from 6 to 8 beacons for 3×3 machines).
• Because multiple beacons have diminishing returns on a single machine, it is generally preferable to spread beacon coverage across many machines rather than stacking excessive beacons on a single machine.
• Logistics and belt routing can become awkward because machines cannot be more than two tiles from a beacon; consider using logistic chests or planning inserter/chest spacing to keep machines in range while maintaining throughput.
• Remember that beacons do not accept productivity modules and they do not themselves receive module benefits, so any energy penalty from modules inside beacons cannot be reduced by placing modules in the beacons themselves.