Reactor Antenna

alaindustrial:reactor_antenna

NuclearLVImplementednuclearreactormultiblockshieldingremoteantennaenergy

Summary

Reactor Antenna is the shell block through which the Reactor Tablet sees the build from far away. Without an antenna the tablet cannot see the reactor and cannot bind to it. The block came out of a player request for remote viewing of a reactor and repeats the decision the inlet and the outlet are already built on: if a wall has to have a function, it goes to a purpose-made piece of wall.

The antenna takes up a casing cell. To the room scanner it is casing: it is not a breach, it does not count against the glass cap, and it does not break the seal. The controller finds it with the same walk over the shell that it uses to collect the outlets, so the antenna needs no search of its own and no back-references.

The antenna pays for its work: it has a small EU/FE buffer of its own and a constant upkeep. Without energy it does not work, and the tablet shows "antenna unpowered". The upkeep is there from the very first tier: if it were introduced later, antennas players had already built would stop working after an update.

Status: spec. The buffer and upkeep numbers are in (see "Balance").

What it does

The antenna stores no reactor data and transmits nothing itself: the tablet takes the data from the controller while the antenna is in service. The antenna only permits the link — and takes energy for it.

Where it can stand

• A reactor with a room. The antenna goes in place of a casing cell in a wall, floor or ceiling. The controller collects it on the walk around the perimeter, together with the outlets; it lands in the room's antennas list on the nearest scan (= 40 ticks), not instantly.
• A bare reactor (no room). The antenna counts if it touches the controller with a face. A bare reactor has no perimeter walk, and touching is the only way for an antenna to be found.
• A room may hold several antennas; the link is measured from the nearest powered one.
• An antenna that is outside a room and not next to a controller does nothing: the controller will not find it, and a tablet cannot be bound to it — binding records the controller, and such an antenna has none.

The room stays sealed

The antenna is a shell block, and the scanner sees it as casing: not as a port and not as glass. It is the same chain as for the outlet and the lamp:

• it does not count as a breach — it can go in any cell of a wall, floor or ceiling;
• it does not count against the = 30 % cap;
• it carries formed/edge and, along with the whole wall, switches to the seamless texture once the controller has accepted the room (see "The seamless look").

With the antenna there are eight blocks the scanner accepts as wall: the former seven — casing, glass, lamp, airlock door, inlet, outlet and a controller in the wall — plus the antenna.

Energy

Where the buffer is refilled from, in order:

1. An external cable to the mast cell (see "Appearance") — the main route. The antenna is an ordinary consumer on the network.
2. The controller. If there is no external power, the controller tops the antenna up itself from the reactor's buffer — the same way it feeds the outlets. A reactor that is idle and selling no energy feeds the antenna too, as long as there is something in its buffer.
3. Neither. The antenna does not work: there is no link, and the tablet shows "antenna unpowered".

The upkeep is charged on the model of the upkeep of the Monitor Wall core: a constant fee for the time that has passed, not for an event. The upkeep does not depend on whether anyone is looking at the tablet or whether the reactor is running: the antenna is either in service and paying, or it is not.

Range and tier cost energy, and there is no way around it. Nothing but energy itself switches the antenna on.

The order, "antenna before selling energy or after", when the reactor's buffer is short for both, is settled at implementation and written down here. One limit is known in advance: feeding from the buffer stops when the buffer is empty — at zero charge), so an antenna that lives on the reactor alone goes dark with an empty reactor. This is expected: to look at a stopped reactor with no energy in it, the antenna has to be powered by a cable.

Redstone alarm output

The antenna's boom gives out a weak redstone signal from the reactor's state: run dust or repeaters from it to an alarm lamp, later a siren, or any circuit of the player's. Only the boom gives the signal; the antenna cube in the wall does not.

• The scale is the one the panel and the siren use: the room's heat, or instability for a bare reactor. A bare reactor has no meltdown line, so it gives 15 only during the countdown; three racks hold its scale at 90 %, so a lava farm on three racks gives 7 all the time — that is correct.
• Hysteresis. Both levels switch off lower than they switch on, so the signal does not chatter while the scale wobbles at a threshold: 70 ↔ 60 for 7 and 85 ↔ 70 for 15. The meltdown latch is saved with the controller.
• The signal is the last step of the controller's tick, after the countdown, so it never lags a tick behind. The world is written only when the level changes — no extra neighbour updates.
• A weak signal, like a daylight detector's: dust, a repeater, a comparator or a lamp next to the boom takes it; it does not power the solid block beside it.
• No link — no signal. An antenna with no power, no upkeep paid, a built-over boom, a broken controller or the controller's chunk unloaded gives 0: a boom with a signal checks the antenna behind it every 20 ticks and drops the signal when it is not transmitting. So an unpowered antenna looks just like normal; check the link with the tablet (it shows "no link"), and the boom's tooltip warns about this.
• The controller never gets the signal. It runs while redstone reaches it, and an alarm reaching it would start the reactor by itself. The boom never touches the controller, in a wall or by a bare reactor (its cell is in front of the antenna, the controller beside or behind), and a weak signal does not pass through a solid block. For an automatic emergency stop, put an inverter (a redstone torch) on the way to the controller: the alarm turns the torch off — the controller loses its signal — the reactor stops.
• Tell 7 from 15 by dust length (a lamp more than 7 dust from the boom lights only in an emergency) or with a comparator.

Block properties

The hardness must not be lower than the wall's: the antenna must not be the easiest place to open the wall.

Appearance

The look is variant 09, "Yagi", chosen by the owner on 2026-11-02 from ten sketches (tools/model_sources/reactor_antenna_concepts/, source v09_yagi/reactor_antenna.bbmodel): a casing cell with a mast sticking out of it, carrying three elements.

• Direction. The block has six directions: when placed, the mast points at the player, that is, outside the room, since a room is built from the outside. Together with formed/edge that makes 24 blockstate variants.
• The mast is a separate block. The mast reaches 14 px into the neighbouring cell in front of the wall and stands there as its own block (reactor_antenna_mast, no item): it has its own light, collision and outline, you can stand on it, and the cell cannot be built over. The antenna can be placed only if that cell is free, and it places the mast itself; the mast disappears with the antenna, and a mast broken by a player breaks the antenna too (the antenna drops). A mast knocked out by an explosion is regrown by the antenna as soon as the cell is free again; while the cell is built over, the antenna stays silent.
• The cable enters the antenna through a socket in its outer face under the mast. A cable brought to the mast cell from the side, from below or from the front gets a copper sleeve slightly thicker than the cable: from its own side of the cell to the centre and on straight into the socket. The sleeve is drawn only while a cable is connected; with no cable only the socket shows. A cable cannot be brought from the antenna's own side (that is the wall) or from the side above the Yagi elements (the sleeve would run into them): for an antenna in a wall that is the top, for an antenna on a roof the south side of the cell, in a ceiling the north side. To a free face of the antenna itself (on a bare reactor) the cable comes as before. How this look came about: first the socket on the floor hung in the air, then a duct along the wall lay on the floor — the owner asked for the cable to enter the block directly (in-game checks on 2026-11-02 and 2026-11-03).
• The item icon shows the whole antenna — the cube with the socket and the mast, scaled down to fit the slot.
• Seamlessness. The unformed, formed and edge models take the casing from one atlas, like the other shell blocks.

Recipes

Shape "3×3": SWS / CRC / SWS, output 1 antenna.

The antenna costs one casing cell plus an advanced circuit and four plates: a wall block with a function, but not a choice among the expensive ones. The recipe unlocks in the recipe book when the inventory holds casing and an advanced circuit.

Progression

• Tier: LV by energy intake (the upkeep is small); the reactor itself stays HV.
• Requires: the nuclear stage (shielding plates and the reactor controller), because the antenna has no point without a reactor.
• Unlocks: the Reactor Tablet and remote viewing.

What comes next (not in this spec)

• Signal booster cards in the antenna —.
• A reactor siren —.

There are no empty slots or outputs "for the future" in the first version.

Related

• Reactor Tablet — who the antenna is needed for.
• Reactor Controller — what finds the antenna and feeds it energy.
• Reactor Outlet — the model of a shell block with a function and a buffer of its own.
• Reactor Lamp — the model of a shell block with a look of its own.
• Reactor Inlet — the same principle for fluid.
• Reactor Casing — the rest of the shell and the seamless look.
• Monitor Wall — the model of a constant upkeep.

Crafting

Shaped Crafting

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Reactor Antenna