Radio Emmisions from a PC

:confused Hi I've had a hand held pair of walkie talkies for some time now they have 8 channels and usually just pick up random strangers in close proximity, but today for no apparent reason CH3 on them are picking up what sounds like data bursts and i can "hear" my mouse when i move it :confused has anyone else experienced this? It is just so strange and out of the blue. I know its my PC as I shut it down to test and the channel became its normal clear no activity self. then turned pc on again and could hear all weird data sounds as it boots up mixed in with background noise. What causes this? its freaky ! Its never done it before I can normally scan all chanels all night and pick up nothing while using the PC. Bizarre

 

have you recently changed hardware in the machine?

or moved the machine and wiring around maybe?

 

HI AMD,

Any radio device too close to another device can and will be picked up regardless of the frequencies being used. In addition any device that generates Square Waves will be picked up. Square waves appear to radio as all frequencies. There is a lot more to it than this but I hope this helps a bit.

Luck, Jim

 

If it never did it before and has just started it's possible the filter capacitor across the mains supply in you PSU has failed, don't just replace with anything as this is a special class X capacitor designed for direct connection to the mains.
The dielectric of an ordinary capacitor would be ripped apart in no time but classX type have self healing dielectrics.

 

Sorry, but that is incorrect. The wavelength of any radio frequency signal is a "physical" property of that frequency, as defined by the Laws of Physics. In order for this energy to "radiate" it must have an antenna of that wavelength, or one of its harmonics. If the antenna is not the right length, it will be out of frequency range and there will be no transmission, or receiving of the signal. So the frequency, or range of frequency very much matters.

This too is not quite right - but you are correct that there is a lot more to it. Squarewaves are not the issue. We are really talking about "high-speed switching" devices that, as an unwanted side effect, often generate or are susceptible to RFI/EMI. Engineers are well aware of this effect - as are spys. So a properly designed circuit or device will prevent RFI/EMI, negate it, block (shield) it - or do all three - much depending on the budget and quality of design and manufacturing of the product. That prevents transmitting, and prevents any RFI/EMI from affecting it.

It is likely the shielding for one or more of your devices - including the walkie-talkies - is insufficient, failed, or was damaged. I agree with voodoo, a component may have failed in the PSU - which uses switching devices too. Bad shielding is often caused by something simple, like a loose connection. So you need to make sure all your cables are connected properly. Also, a bad facility ground (Earth) at the wall outlet can affect shielding. Everyone (home owners and renters alike) should have a AC Outlet/Ground Fault Indicator Tester. There are models for every country.

Jim is right when he implies these RF signals are everywhere - cell phones, wireless phones and networks, microwave ovens and towers, computers, TVs. They all have the potential to interfere with other devices.

 

It is important to remember that walkie-talkies, cell phones and many wireless devices ARE radios - with antennas cut to length for their frequencies, and amplifiers to boost the signals. No shielding there. Most cell phones operate in a range from around 800MHz to about 2GHz range.

 

Hi Dig,

I was a trained radio tech before being an electronic tech starting 60 years ago. My statements are brief descriptions of known facts.

Jim

 

No disrespect meant Jim, and I do note you made it clear it was a brief description. We seem cut from the same cloth - as I too was a radio tech and technician - in my case, for the Air Force - though you got me by 25 years - I started in 1971. - I have also worked a lot with digital communications technologies - RF, light, and wire - involved early on, and forever with TEMPEST issues.

I think we both agree that radio devices (walkie-talkies, cell phone, some wireless devices) are more likely to cause interference (when transmitting - and in extreme case, while receiving), and are more susceptible to interference from outside sources. I think we also can agree that proximity, shielding, grounding, design, and manufacturing quality/precision affect interference.

I note the topic here was about hand-held radio transmitters/receivers ("walkie-talkies") picking up what sounded like data bursts. I have no doubts the computer is at fault - I only take exception to the absolutes - "any radio device"..."will be picked up"..."regardless the frequency".