[Elecraft] plexiglass

[Geoffrey Mackenzie-Kennedy]

Alex NS6Y wrote:

> In my reading about green radios I can't afford (but want anyway) and  in 
> various readings I've heard that detecting the 455-kHz LO of a  superhet 
> isn't all that hard, and that for instance in countries that  require a 
> radio license, they use such techniques to check if people  in their 
> houses have radios (or TVs) that they're not on record of  having licenses 
> for! And, in a lot of the military radios, the  shielding is VERY good so 
> that detection is much harder to do.

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In 1940 the SWBC radio for use by passengers, on the ship that was used to 
evacuate a bunch of us youngsters to Africa, was put into a solid locked 
metal box. I believe that this was to prevent U-boats detecting any 
radiation from the receiver, most likely a superhet. The loudspeaker was 
outside of the box and there must have been an external antenna. Maybe 
overkill or wishful thinking.

73,
Geoff
GM4ESD