The Frequency Diary
A night-shift security guard begins keeping a log of unexplained sounds in a downtown Toronto office building. What starts as a maintenance complaint becomes something stranger — and then, slowly, something she can explain.
Published 2025-03-24
The technologies in this story — FMCW radar, WiFi CSI, IMSI catchers, acoustic side channels — are real and covered in detail across this site. Priya Anand is not. I. The Log The first entry was not dramatic. Nov 3, 02:17 — Clicking sound near elevator bank, 4th floor. Checked for loose panel. Nothing. Will monitor. Priya had been keeping a maintenance log since her second week at the building, not because anyone asked her to but because she was the kind of person who wrote things down. Her mother called it a nervous habit. Her ex husband had called it something less kind. She called it thinking out loud on paper. The building was a twelve storey commercial tower in downtown Toronto, financial district, the kind of place that emptied completely at six and filled again at eight. Between those hours it belonged to her and the cleaning crew and the hum of the HVAC system and whatever else lived in the infrastructure. Nov 5, 03:44 — Same clicking. Fourth floor only. Sounds like it follows me down the corridor. Maintenance ticket raised. Nov 7, 01:58 — Clicking again. Brought personal phone to record. Difficult to capture. Sounds like it's coming from inside the ceiling, or possibly from the walls near the elevator. Cannot locate source. She had worked nights for eleven years — first in a hospital, then in a data centre, now here. She had learned that buildings had personalities at night, that the sounds they made between midnight and five were the sounds of a machine running on minimum power, cooling and settling and occasionally ticking in ways that meant nothing. This was…
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