Here are links to a fascinating technical article on Television Detector Vans in the UK, used to track down clandestine TV viewers who neglect to pay their television licenses there. At 12 pounds GBP a month, that works out to around R3000 ZAR per annum...
The article appears in the Southgate Amateur Radio Club in the UK:
http://www.southgatearc.org/news/2021/january/tv-detector-vans.htm
The original article in Hackaday.com is here:
https://hackaday.com/2021/01/18/tv-detector-vans-once-prowled-the-streets-of-england/
Grateful thanks to Lem ZS1LEM for the info!
