Current bugbears

[Giles Jones]

On 4 Sep 2007, at 18:38, Richi Plana wrote:

>> with. See http://en.wikipedia.org/wiki/Heterodyne for a very
>> basic description.
>
> Fascinating. So "passive receivers" really aren't? Or are there  
> classes
> of receivers which are (no amplification or very sensitive pickups)?
> Prolly off-topic, but I sure am curious. Are there no radar detectors
> which don't give off their presence?
> --

In the UK you have to have a TV licence if you receive TV. They use  
detector vans and can tell if you're watching. So there is enough  
signal emitted when receiving I guess.