Bill S wrote:Would airport security even be able to recognise one? And yes - regularly find various bottles of liquids after security - yet to have one found ....
I was more thinking, 'what is this strange electronic device you have in your hand luggage'. I'd have thought custom electronic devices would be 'frowned upon' like custom electronic shoes

Not too difficult to find thisor this source for jammers.
The high fine is for use in the US - mainly as they also have been used to block law-enforcement and security communication usually with high powered devices - and even they are difficult to find without multiple directional receivers.
Thanks for the uk site, I missed that when I last looked for one. The uk one doesn't send them from within the uk, it sends from china, and you take the risk of the discovery and potential fine. How likely that is, I'm not sure... I've heard people use the $10 marked as gift thing for some things, but I suspect that can be hit and miss...
As for the legality:
"The use of any apparatus, whether or not wireless telegraphy apparatus, for the purpose of interfering with any wireless telegraphy, is an offence under the Wireless Telegraphy Act 2006. It is an indictable offence that on conviction in Crown Court carries a maximum penalty of two years imprisonment and/or an unlimited fine. The courts can also order forfeit of any apparatus used in the commission of the offence."
That law has been enforced on sellers in the uk.
http://stakeholders.ofcom.org.uk/enforc ... t/jammers/