There was engine noise in the pre-dawn wind. At first light you found the crate at the end of the street, its chute still hooked on the power line, the crate number blurred by rain. Cans, hard biscuit, reinforcement kits... and pressed into the bottom, a kraft-paper tube. Inside were sheets folded many times over: the full wiring for a transceiver, with substitute parts pencilled in the margins. The handset lit up at the same moment: put it together and we can fix your position - and the signal around you gets better too.

Just before dawn something landed heavily outside the terrace. A crate - the chute snagged on the neighbour eaves, dragged crooked. Cans and reinforcement kits inside, and at the very bottom a kraft-paper tube. Inside it, blueprints - a transceiver, the wiring drawn dense, someone notes in the margin naming substitute parts. A line followed on the channel: build it to the drawing and we can fix where you are - and the signal through here holds up a little better too.

Something thumped in the yard in the small hours. At first light you went to look: an airdrop crate, come down on the concrete of the loading bay, split at the corner. Cans, reinforcement kits, and a kraft-paper tube. Inside were blueprints - a transceiver, with a parts list itemised down to the last piece, several of which are already on your shelves. The man on the channel said: build it and we can fix your position, and prop up the signal round here while we are at it.