Handheld Radio Interference From CPU

Sounds like you are getting feedback from the speaker. Just like if you use a public address system and happen to walk near the speaker with the mike.

If you don't need the little speaker thats included with your computer disconnect it.

Hi Scotch drinkr,

Thanks, I will try to isolate the built in CPU speaker as noticed it is operational.

Many thanks and I will give feed back after.

Kind regards

Roman

Hi scotchdrinkr,

Many thanks, however after isolating the speaker from my CPU problem still exist.

Kind regards

Roman

Is your radio or the computer making the humming noise?

I've noticed some of the computers here will tell me when a call is coming in on my cell phone about 2 seconds before my phone rings. Not all of them just some of them do this.

Hi Scotchdrnkr,

It was my Radio making noise not my CPU. infact I noticed when the humming sounded and the radio is on my belt, if i turn and position hiding my body the sound come off, but if go back in the same position same humming sound back.

As I google and read in one article says this problem can't b e resolve.

Kind regards

Roman

Hi,

One thing that emits RF from a CPU is the Power Supply Unit. CPUs have Switching Power supply which are normally operating from 100KHz to about few MHz, which is why sometimes RF leaks from the power supply due to degradation of components (especially coils). Try to change the power supply unit with a new one. That might work.

Hi Guest,

Thanks for the advise, soon I done with Scotchdrnkr advise, i will do yours next, and i will keep you inform on what will happened.

Kind regards

Roman

Hi Guest,

Thanks for your input as this is the nearest reply where I do some rectification and the humming sound was gone. What I found and did was the earth ground and the neutral was interchanged. I give you vote for GA.

Kind regards

Roman

Warning: I don't know a lot about this sort of thing.

Turn the volume on the radio down a bit, then move it around close to the PC. This way you should be able to trace the source of the interference more accurately. If the interference seems to be coming from the whole thing, then the case is probably "singing": try to reduce the impedance of the case to ground.

To me, it is RFI. Something changed upon changing out the CPU. Could be simple as the computer cover not being secured properly (are all of the cover screws tightened properly? Are there missing ones?).

Hi Bill,

Thanks for your input, all screws and covers are in placed and in order.

Kind regards

Roman

Aside from a bad ground, you will find that computers are a wonderful generator of broadband noise at RF frequencies from several hundred kilohertz up thru 5-10 Mhz if not shielded (and this means the CRT and other cables too).

The major issue is that not only does the power supply switch, but the entire computer is putting out pulses onto it's PC boards all the time. Sharp edged pulses which are more common with faster computers generate multiple frequencies and harmonics of those frequencies all the time. Other than filtering and metallic shielding of the case and cables, you're stuck with simply physically isolating the radio from the computer (and the cell phone too). Cell phones have similar issues, since they also manufacture digital pulses at multiple frequencies.

Bob S

Hi to everyone!!

Thanks for all of your input, I believed I managed to sort the problem out in changing over the earth and neutral terminal from the power supply. and the humming sound was gone!! hopefully that's all the problem coming from but almost 1 hour now of observation still fine. the nearest answer from the guest that i gave GA vote.

Kind regards

Roman