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Audio bug + microwave motion sensor hidden inside wall  

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forensicgl
(@forensicgl)
New Member

I suspect the presence of a hidden audio bug, paired with a microwave motion sensor device to detect people presence in a house room and covertly listen their speech.

The device is located inside the masonry, exploiting the cavities of the bricks to push it from the neighboring house in order to reach a room in the other property.

When someone enter the suspect room, the activation of something that suggests the presence of an electromechanical mechanism triggered by a motion sensor, can be clearly heard originating from a specific point of the wall, probably due to a malfunction of the hidden device.

I cannot break the wall to not compromise the investigations, but I have to produce evidence for the authorities: what instruments can I use to detect microwaves without using an expensive spectrum analyzer ?

 

PS. I have found on Amazon different cheap electromagnetic field radiation detectors, but I don’t know if these devices can be effective to find microwave detectors that work in different frequency ranges (e.g. 2,4 – 10 – 24 GHz)

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Posted : 18/11/2020 6:05 pm
jaclaz
(@jaclaz)
Community Legend

Hmmm.

An audio bug (i.e. in practice a microphone+a transmitter) or

an audio bug (i.e. in practice a microphone+a recorder) or

an audio bug (i.e. in practice a microphone)?

At face value none of the above would need a microwave detection, I mean, if the idea is to hear/record/transmit (private) conversation, then voice/noise activated devices would do, without any need for microwave/proximity/motion detection. 

Besides these microwaves need to be powerful enough to cross the wall or at the very least the plaster (I mean, common motion sensors as used in alarms or lamps "see" through a thin semi-tranparent plastic screen or through a "hole").

AFAIK you need an EMF meter, but usually they reach 6 GHz, example:

https://www.trifield.com/

which should be enough for common motion detectors that operate at the most at 5.8 GHz, for higher frequency (RF) they usually top at 8 GHz, other examples:

http://www.extech.com/products/480846

http://www.tenmars.com/m/2001-1682-689903,c19121-1.php?Lang=en

Higher frequencies will cost you much more, yet another example:

https://aaronia.com/spectrum-analyzers/  

https://aaronia.com/spectrum-analyzers/spectran-v4-handheld-sweep-analyzer/

Anyway, you can try shielding the area (with - say - a sheet of metal) and see if the click still happens.

jaclaz

ReplyQuote
Posted : 18/11/2020 7:53 pm
forensicgl
(@forensicgl)
New Member
Posted by: @jaclaz

Hmmm.

An audio bug (i.e. in practice a microphone+a transmitter) or

an audio bug (i.e. in practice a microphone+a recorder) or

an audio bug (i.e. in practice a microphone)?

At face value none of the above would need a microwave detection, I mean, if the idea is to hear/record/transmit (private) conversation, then voice/noise activated devices would do, without any need for microwave/proximity/motion detection. 

I cannot say anything about the type of microphone that might be present, but a microphone activated by voice/noise would be activated by the traffic noise in my area.

Besides these microwaves need to be powerful enough to cross the wall or at the very least the plaster (I mean, common motion sensors as used in alarms or lamps "see" through a thin semi-tranparent plastic screen or through a "hole").

but yet, in the instructions of the alarm devices, it is always recommended a careful adjustment to avoid false alarms due to excessive calibration power that could cause the microwaves to cross the walls.

AFAIK you need an EMF meter, but usually they reach 6 GHz, example:

https://www.trifield.com/

which should be enough for common motion detectors that operate at the most at 5.8 GHz, for higher frequency (RF) they usually top at 8 GHz, other examples:

http://www.extech.com/products/480846

http://www.tenmars.com/m/2001-1682-689903,c19121-1.php?Lang=en

Higher frequencies will cost you much more, yet another example:

https://aaronia.com/spectrum-analyzers/  

https://aaronia.com/spectrum-analyzers/spectran-v4-handheld-sweep-analyzer/

Could a device like this be enough ?

https://www.amazon.com/Walmeck-Microwave-Radiation-Detector-0-9-99mW/dp/B07DWZHTKQ

https://www.meterk.com/p-e5175.html

https://www.meterk.com/p-e2470.html

Anyway, you can try shielding the area (with - say - a sheet of metal) and see if the click still happens.

Perhaps a thermal blanket might be enough for the task ...

This post was modified 2 weeks ago 4 times by forensicgl
ReplyQuote
Posted : 19/11/2020 5:38 pm
jaclaz
(@jaclaz)
Community Legend

The termal blanket might do, though personally I would use an aluminium plate.

Those meters you listed top at 2.5-3.5 GHz or less, the first one is essentially a microwave (oven) leakage detector, they may well detect the thingy nonetheless, but if the thingy works at highere frequency they could miss it.

Maybe, among el-cheapo devices, you would be better served by bug detectors *like* :

https://www.amazon.com/Detector-Wireless-Amplification-Sensitivity-Handheld/dp/B07G62S5WR#

but cannot really say.

jaclaz

ReplyQuote
Posted : 19/11/2020 6:53 pm
forensicgl
(@forensicgl)
New Member

Jaclaz thanks for the advice and sorry for the late reply.

I will try first the cheaper solutions like thermal blanket, metal foil, bug detector and maybe rent an EMF meter and spectrum analyzer.

I had also explored the possibility of using a motion detector to be set in "listen only" mode, so that it would only pick up microwaves emitted by other motion detectors, but it seems that these devices do not support this mode, at least according to Bosch tech support …

ReplyQuote
Posted : 26/11/2020 6:37 pm
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