> I suppose the heterodyne frequently (the 465 kHz of AM, for instance) can be effectively hidden. Put your whole receiver into a metal enclosure, have a high-pass filter before the antenna connector, and a low-pass filter before the outputs and power connectors.
Yes-- and every piece you mention is "quality radio design 101".
> Such a device would likely look peculiar enough to be easily recognizable
I'm not sure about that.
The biggest most suspicious thing is, if they're resourced to investigate everyone with a piece of coax going outside-- where does yours plug into?
Of course, if you're really dedicated-- get a satellite TV receiver, empty out the nice metal box, put the receiver inside ;).
Yes-- and every piece you mention is "quality radio design 101".
> Such a device would likely look peculiar enough to be easily recognizable
I'm not sure about that.
The biggest most suspicious thing is, if they're resourced to investigate everyone with a piece of coax going outside-- where does yours plug into?
Of course, if you're really dedicated-- get a satellite TV receiver, empty out the nice metal box, put the receiver inside ;).