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Laptop NFM emissions

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EricaS

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My laptop emits the surrounding audio as NFM modulation at a frequency of about 115 MHz.
Is this normal?
 

betwixt

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All digital equipment radiates interference, it's an unfortunate side effect of high speed switching signals, they create lots of hamonics at multiples of all the different internal signal frequencies. I would not expect anything intelligible to be radiated though. What do you mean by "surrounding audio" ?

Brian.
 

EricaS

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I hear clear room audio on these frequencies:
117.810; 119.870; 144.450; 148.420; 150.480; 150.580; 152.640; 154.680; 156.740; 158.670; 158.770; 162.770; 162.870; 164.930; 168.900
MHz

Each time I restart the machine the frequencies change by just a little.

Additionally there are transmissions that I think are encrypted or digital?. These occur at 32 different frequencies. Could this a kind of spread spectrum signal?

My laptop is a W530 model:
http://lnv.gy/1LLxfxC
 

betwixt

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From the frequency distribution and the way they start differently each time, I would say those are harmonics of one of the internal switch mode regulators. There are two ways to drop the battery/adapter voltage down to the lower voltages needed by the internal components (typically around 2v - 3.3V). One is to use linear regulators which produce no radio emissions but run very hot, they need continuous high air flow to keep them cool. The other is to use switch mode regulators (SMPS) which are very efficient, run cool but throw out lots of interference. There will be lots of internal filtering to keep it to a minimum so it doesn't disrupt nearby equipment but your receiver is exceptionaly sensitive compared to a 'domestic' one so it highlights the interference more.

The 'digital' noises are nothing encrypted, they are the normal workings of the logic signals, some will be from timer circuits and repetitive, some will be from things like the network interface and video circuits which change according to the program flow.

When you describe "clear room audio", do you mean just a quietening of the background noise or it is picking up sounds from the internal microphone and relaying sounds from inside the room?

Brian.
 
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EricaS

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When you describe "clear room audio", do you mean just a quietening of the background noise or it is picking up sounds from the internal microphone and relaying sounds from inside the room?
Brian.
I think it picks up sound from the microphone, I hear the traffic outside, conversations in the hall, even if I whisper in the room I hear it.
My colleague had a look of horror on her face when she listened in.

Can I assume this was delibratley done?

The range is just sufficient to reach those antennas I showed earlier.

- - - Updated - - -

The 'digital' noises are nothing encrypted, they are the normal workings of the logic signals, some will be from timer circuits and repetitive, some will be from things like the network interface and video circuits which change according to the program flow.

Brian.
My colleague has an identical laptop but there's nothing on hers?

- - - Updated - - -

I can stop the RF by going into device manager -> sound, video and game controllers -> and disabling high definition audio device.
 

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It is certainly unusual for it to do that. There is a property of almost all components called 'microphony', they convert vibrations to tiny changes in their electrical properties which can be picked up elsewhere but this sounds more like the HD audio is using the in-built microphone which in any case will be far more sensitive to sound.

I would have to see the laptop to investigate further. There are legitimate reasons why it could modulate a carrier signal, even if unintentionally but it would be unusual to do so because the microphone signal is normally digitized early in the circuitry. In it's digital format, even if you could hear the signal on the radio, it would be nothing more than a constant buzz with little or no indication it was carrying any sound at all. For now, you should be able to turn the HD audio on again, assuming you use it for other purposes, but mute the microphone input from the mixer control panel (I'm not using Windows so I can't tell you exactly where the control is).

Brian.
 
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EricaS

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There are legitimate reasons why it could modulate a carrier signal, even if unintentionally but it would be unusual to do so because the microphone signal is normally digitized early in the circuitry. In it's digital format, even if you could hear the signal on the radio, it would be nothing more than a constant buzz with little or no indication it was carrying any sound at all. For now, you should be able to turn the HD audio on again, assuming you use it for other purposes, but mute the microphone input from the mixer control panel (I'm not using Windows so I can't tell you exactly where the control is).
Brian.
It's delibratley placed outside of the FM radio band (88 to 108 MHz) so that it can't be accidentally found on a normal radio.
I'm certain its being used to eavesdrop on me.
I tried to mute the mic on the sound panel but it doesn't switch off the RF. The only way is to disable the audio device in the control panel.

Is it possible the other 32 frequencies are the digitized audio form? How can I demodulate that?

The laptop has no FM transmitter or receiver.

And I'm sure the telephone is doing the same thing!
That's where it all started, I just stumbled upon the laptop because its next to my telephone.
 

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If the microphone is muted it should stop eavedropping so your security is good again. The chances of there being a digital audio transmitter are almost zero, especially as the sound is obviously being routed through the existing audio devices in the laptop. A digital audio transmitter is quite a complicated device to build, especially in a small space and it would also require a power source and in-depth knowledge of the internal circuitry of the laptop to be able to interface to it.

I suspect the audio transmission, is either accidental from an unstable amplifier or it is being deliberately converted to FM as part of the normal operation of the laptop but leaking out when it shouldn't. I'm afraid the only way to narrow down the source is to open the laptop and 'sniff' around with a signal probe.

Just as a check, can you confirm the laptop doesn't have Bluetooth, if it has, try turning it off, the settings are probably in the control panel somewhere but not under the audio devices category. The other possible, but unlikely source is an SPDIF interface if the laptop has one. Some have a dedicated SPDIF socket, some hide it behind the headphone jack socket. If you look closely down the headphone socket hole in a dark room you would see a dim red light if it has one behind it.

Brian.
 
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vfone

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Your previous thread similar with this (https://www.edaboard.com/thread337161.html) got more than 3600 views, which I think is good for the Pay-Per-Click advertising of this forum.
But in the same time, I think is cheaper and less time consuming for you to buy a new (or second hand) laptop which will fix all (and I mean all) your related problems.
 

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I've seen reports of eavesdropping malware, which can turn on your mic and send its output (digitized) to a remote listener on the internet. Same with your camera.

If you right-click on a Youtube video while it is playing, you can choose 'Settings'. The window contains several options (which apparently have to do with Flashplayer). One adjusts your mic. Another chooses the camera, if it finds one. I have not looked into the possible uses for this, but it certainly makes me wonder.
 
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vfone

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This thread is rolling again, over and over.
The poster mentioned very clear that there is an FM modulated signal at particular RF frequencies and is NOT about a remote Internet communication (audio or video), which is a different story.
I am not aware to exist on the market a laptop with factory made INTERNAL FM modulator, which can be activated remotely by a malware application.
 

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I think that's a different thing Brad.

Flashplayer can provide a 'Skype' like link for some interactive programs which include the ability to turn on the microphone and webcam. As far as I know they can only enable them for connection over the network interface, there should be no electronics inside the computer for intentionally broadcasting locally by wireless means, especially using FM. I checked on a Windows PC (running XP) and there is a "Flash Player Settings" option in the control panel, make sure under the "camera and Mic" tab they are blocked completely if in doubt about whether they are being used. It won't stop the signal being radiated but it will ensure the microphone can't be turned on remotely by visiting Flash pages. There is also a tab called "Advanced", I would use the "Delete All" button to wipe any access to the settings from existing programs you have installed.

The same philosophy applies to all other programs that use the microphone. Make sure none of the "social media" applications like Skype, Yahoo messenger, Ekiga and the likes are started automatically when the computer boots up.

Brian.
 

BradtheRad

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I think that's a different thing Brad.
..........
The same philosophy applies to all other programs that use the microphone. Make sure none of the "social media" applications like Skype, Yahoo messenger, Ekiga and the likes are started automatically when the computer boots up.

Brian.
If we can rule out the possibility I brought up, then that's fine. I just thought we ought to cover all bases. Something like the way Sherlock Holmes approached a mystery. 'Eliminate the impossible.'

There is still the idea which you pointed out, that a remote computer might control another computer via internet, or network, or wifi.

Therefore every so often we ought to check that the mic is turned off, etc.

Microsoft sends out myriad updates to Windows users. I see maybe half of them claiming they block another vulnerable doorway through which an attacker can gain control of our computer.
 

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The only real probability here is that this user EricaS is suffering from severe paranoia
last time it was the phone doing things that are impossible, now its the laptop
The next thread she starts, it will be the VCR or the TV or maybe even the toaster

the continuation of responses to her threads just fuels her paranoia even more
Are you guys really going to do this ??

Dave
 
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BradtheRad

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Speaking for myself (and not for other moderators)...

As it has turned out, these two threads speculate on various methods by which a telephone or computer might be bugged... Or might not be bugged. Obviously it is a topic of interest to many readers. Several of our knowledgeable contributors have posted, giving their explanations about why and wherefore.

It is not known for sure who EricaS really is. Nor can we really know her (or his) real situation, nor real frame of mind.

So it's no less valid for one poster to answer to the science within this discussion, as for another poster to express skepticism about its benefits. It is still within forum guidelines.
 
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SunnySkyguy

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You can locate the source of your bug with a small loop antenna and SA to pick up near field emissions. Let the diameter of the loop be same or less than gap of about a few cm.

You might also try a speaker as an antenna for near field sensing using the coil to increase sensitivity.
 

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You can locate the source of your bug with a small loop antenna and SA to pick up near field emissions. Let the diameter of the loop be same or less than gap of about a few cm.

You might also try a speaker as an antenna for near field sensing using the coil to increase sensitivity.
Are there any videos on YouTube showing how to do this?
 

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There is so much bunkum on Youtube and the internet in general that I wouldn't trust it even if it did exist. There is even a video explaining how to generate unlimited supplies of electricity using only resistors!

The probe is easy to make but as you have already pointed out, your R20 uses an internal antenna for some bands and that would be very difficult to disable. However, it is unlikely the internal antenna is being used at such high frequencies. I suggest this, it isn't a scientific instrument but it should suffice to find the locality of the emission:

1. disconnect the external antenna. I assume it has a standard BNC connector so it should be easy to remove.
2. Wire a good quality screened cable (suggest RG174) about 1.5m long to a BNC plug to plug in as a replacement for the antenna.
3. At the other end of the cable, fabricate a simple probe. Tape the cable along the side of a plastic ballpoint pen and around the tip, wind three turns of thin insulated wire. One end of the wire goes to the cable inner, the other to the cable shield.

This makes a crude 'near field probe', a poor antenna that picks up only local produced signals. Use the radio signal strength meter to see how much signal it is picking up then move the probe around, holding the pen at the opposite end to the coil, and see if you can find the peak in the signal strength. If the peak isn't easy to find, try using a one turn coil instead to further reduce it's sensitivity.

Brian.
 

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