Car key remotes myseriously stopped working on Elgin Street between Drummond Street and Lygon Street. Credit:Joe Armao, Fairfax Media. Visitors to Carlton would spend chunks of time waiting for the beep, flash or clunk to signify their chariot had been successfully protected. No luck. Was it dodgy batteries? The newsagent was doing a nice business out of it. But no, drive around the corner and the electronics would start working again. The enigma seemed to be focused in one small pocket: Elgin Street between Drummond Street and Lygon Street. Nothing as serious as ships disappearing into thin air but still pretty eerie. What could be causing this disturbance?

Sarah Layton tries to open her car with the remote control but it won't work. Credit:Joe Armao, Fairfax Media. Events of a couple of weeks ago really kicked off the theories. A patient at Carlton Dental walked into the reception to say that his car wouldn't start. After three hours the car had to be towed away to a mechanic. When it arrived, they found nothing wrong with it. The frequency being registered on Elgin Street - 434 MHz. It had to be linked to the keys.

Perhaps it was caused by the mobile phone towers on top of the shopping centre across the road. Or maybe an enterprising thief was jamming the signal of the keys as part of a break-in spree. A row of shops where remote controls on car keys stopped working. Credit:Joe Armao, Fairfax Media. A more scandalously inclined theorist suggested it might be police listening in on a bunch of mafiosi plotting a drug deal. This is Carlton after all. "We've been asking more questions and it's become much more noticeable in the last week," said Dr Barry Johnson, who has run Carlton Dental for 25 years. The "Elgin Rectangle" where car key remotes stopped working. Credit:Google Maps

"No one would believe that there was an interference with our car locks." Across the road at Elgin Lotto and Tobacconist, Mal Virk said he noticed when more people than usual were coming in asking him to replace their car remote batteries. The dentist where the problem originated. "That's when we realised that actually it's the frequency that is jamming up, so if they go a block that way or that way it works," he said. Mark Johns, at Elgin Printing, said he noticed a rise in car alarms going off: "It's not coincidental, there's just too many," he said.

So who do you call in this situation? The police have bigger things to deal with. The council didn't know how to help. The power company laughed it off. After The Age visited the site last week to check if the problem was real (it was), a call was placed to the Australian Communications and Media Authority. A field officer subsequently paid the area a visit with a spectrum analyser, which found a constant signal at the frequency of 434 MHz– the same used by car key remotes. After walking around with the analyser, it appeared the strongest reading was coming from the doorway at the dentist.

The culprit? It wasn't a frequency jammer or clandestine radio broadcast but a doorbell. A fault with a transmitter used as part of a doorbell sensor at Carlton Dental had knocked out car key remotes across the whole street. ACMA said this kind of thing doesn't happen very often but can sometimes affect other devices like garage remotes. A few years ago in the US, homeowners in California started noticing that their garage doors had stopped opening remotely after a nearby military base began testing radios on the same frequency. While he's happy the mystery has been solved, the kicker is that Dr Johnson provided the original tip-off about the problem.

"It's us of all people," he said. "I knew something around the area must have been causing the problem but I had no idea it was ours. "Now it's up to me to fix it."