It was late — the kind of late where the streets are empty, and the hum of distant transformers fills the silence. I was staying overnight in the same city as an industrial area, about 200 km from home. Work had me stationed not far from the head office of a company that also operates a major site near where I live.
A few months earlier, I’d been combing through the ACMA database and stumbled across a handful of UHF frequencies licensed to the company. Strangely, I’d never logged any activity from them at home — dead air every time I checked. That got me thinking: maybe they only use them locally, near their main base of operations.
So, scanner packed, ScannerFreakDB ready on my phone, and coffee in hand, I decided to find out.
Night One
From the hotel, I set up my gear by the window overlooking the industrial estate. The scanner ran all night, CloseCall enabled, antenna pointed roughly toward the cluster of buildings where the company operated. Nothing. Not a blip, not a burst, not even a stray carrier.
It was disappointing, but I wasn’t ready to give up.
Night Two
This time, I decided to get up close and personal.
Just after midnight, I drove out to the edge of their facility — a maze of chain-link fencing, floodlights, and the occasional movement of forklifts in the distance. CloseCall was armed and scanning hard.
I might have gone right up to the gate. And I might have claimed to be lost, asking the guard if “Dave” — a completely random name — was working that night. It worked better than expected. The guard picked up his radio to check, and right then my scanner lit up — 509.XXXX MHz with a CTCSS tone of XX.X Hz.
Bingo.
That single moment confirmed it: their UHF system was active, just quiet unless directly used. I stayed in the area for another hour, tuning the upper end of the band, where I soon uncovered two more channels — one clearly used for site services chatter, and another for operations.
The Real Twist
When I got home a few days later, curiosity got the better of me. I tuned those same frequencies again, just to see.
To my surprise, they were alive — same frequencies, but with different CTCSS tones. The same company, same equipment, but separate tone setups for each site.
That night proved it: the frequencies listed in the ACMA DB weren’t just dead entries — they were part of a carefully segmented radio system spanning multiple sites, quietly linking operations across hundreds of kilometres.
And all it took to confirm it was a late-night drive, a little curiosity, and being “accidentally lost” at just the right gate.
.JPG)