PC messes up AM radio

[littleberry]

I have 3 PC's now. The oldest one, a 500 mhz P3 with a 300 Watt PSU does NOT interfere with my AM radio. The 1 GHz P3 interferes with AM only and it is irritating, but I can still more or less hear the radio talk. The newest one,
a 2.5 Ghz P4, causes a loud tone (probably around middle C)
so loud that I can't hear the talk anymore. None of them
bother FM reception at all. But I listen to AM a lot while
I am on the PC. Is this just a fact of life? Faster PC's
interfere with AM radio? If I take the radio into another
room, all is well. Why does the older one NOT interfere
at all with the AM, but the newer ones do?
What's even more perplexing, the older one usually
has the cover off because I am always fiddling with
it, but the newer ones are all closed up tight and according to hoyle. What gives? Littleberry

 

[folken]

Computers like all other electronic devices emit EMI (electro magnetic interference). The faster you get the more there will be.
Fortunatly there is a way to lessen the problem. In the bios you will find a thing called Spread Spectrum. The clock on the motherboard produces pulses, spikes in these pulses cause EMI. If you turn Spread Spectrum on the computer will modulate the electric pulses in your computer to reduce spikes and in turn reducing EMI.

Using Spread Spectrum will increase the chance of system instability so any type of overclocking is not recommended when using it.

<A HREF="http://www.folken.net/myrig.htm" target="_new">My precious...</A>

 

[sobelizard]

Your typical AM radio uses the ac power cord as the antenna, or may include a short wire. Other than using shielding on the pc's, you could move the radio, if you have the space. There are specialty products available to aid in limiting emi disruption.

<font color=green><b><i>Lizards</font color=green></b> do <b>not</b> taste like <b><font color=yellow>chicken</font color=yellow></b>,<b> <font color=yellow>chicken</font color=yellow></b> tastes like <font color=green><b>lizard.</b></font color=green></i>

 

[Crashman]

No, it's not a fact of owning a newer PC. The FACT is, well, with so many people spewing out crap, the FACT is that you have an illegal PC!

FCC regulations say your PC CANNOT interfere with communications devices. That means things like NO UNSHIELDED WINDOWS and NO UNSHIELDED EXPANSION BAYS. The "loophole" is that you're allowed to use a non-compliant system so long as you put it in a location where it can't interfere with any communications devices!

So yes, I'm saying a 10 year old Gateway case is better than a brand new Lian-Li with windows.

<font color=blue>Only a place as big as the internet could be home to a hero as big as Crashman!</font color=blue>
<font color=red>Only a place as big as the internet could be home to an ego as large as Crashman's!</font color=red>

 

[folken]

Those old cases were definatly built like tanks
Weighed as much too...

<A HREF="http://www.folken.net/myrig.htm" target="_new">My precious...</A>

 

[jamarno]

The 300W supply may contain a better line filter, but some supplies have only a single-stage filter or none at all.

Other possibilities are unshielded cables coming out of the newer computers - keyboard, mouse, USB, cases with windows on them (almost as bad as no case at all) or no metal knockouts for unused drive bays.

 

[sobelizard]

Thanks for the idea for a nic for my neighbor's wife...

<font color=green><b><i>Lizards</font color=green></b> do <b>not</b> taste like <b><font color=yellow>chicken</font color=yellow></b>,<b> <font color=yellow>chicken</font color=yellow></b> tastes like <font color=green><b>lizard.</b></font color=green></i>

 

[jihiggs]

that was random

this is my boomstick!

 

[sobelizard]

Neighbor's wife...older, weighs a ton...

<font color=green><b><i>Lizards</font color=green></b> do <b>not</b> taste like <b><font color=yellow>chicken</font color=yellow></b>,<b> <font color=yellow>chicken</font color=yellow></b> tastes like <font color=green><b>lizard.</b></font color=green></i>