My PC interferes with the radio

[ik9000]

to quote radio head it buzzes like a fridge it's like a detuned radio. Except it's a tuned radio and working all nice and fine until you hit the on switch and the comp fires up. It's not the monitor, and it does it to different radios. I'm running both the radio and the PC through separate Belkin Gold audio surge protectors. It's always done this, just I thought it was the cheap £5 radio alarm I was using. Now I got a much better one, and I realise by comparing it to a third one that it is the PC making the problem. Presume it's time to do the unplug everything internally piece by piece to identify the culprit approach, but wanted to check if anyone has any suggestions.

Is it safe to power up a PSU with nothing connected to it?

[kalniel]

Yes, quite safe, though you'll need to short the power on switch pins to get it to start up.
http://www.techpowerup.com/articles/other/22

[smargh]

Perhaps buy/borrow a UPS to see if the interference is being sent through the mains wiring? Have you eliminated the Belkins? Any speakers?

Also, rule out any wifi you might have on the PC, and perhaps try some nice cable-organising & cover the entire desktop with a DIY faraday cage

Let us know how it goes.

[Agent]

Surge protectors can actually cause this - take it out of the loop for testing.

Also do you have homeplugs? They have known issues with DAB radios (although you don't state DAB or analogue)

[ik9000]

FM and DAB both affected though DAB signal so poor it's hard to tell. Got a big Co-ax ariel installed now and it's helped, but still audibly buzzy with the comp switched on.

I will try removing the surge plug for another brand I have in storage. Not too keen on running it with no SP - never confident in rental property wiring since my gf (now wife) lost her monitor to dodgy electrics in her flat a few years back.

I don't think it's the flat wiring causing the hum since it did the same at my last flat. Radio fine, then turn on comp and radio= BUZZZ

Unplugged all wireless devices (no native wireless to the comp) and no homeplugs in use (in my property anyway)

[kalniel]

Check your mobo manual - you might have a setting (called spread spectrum on gigabyte boards) that does something automagical to reduce RF interference (slightly tweaks the different power phase modules to different values I think to reduce the build up of interference at any one frequency).

[ik9000]

I do indeed have spread spectrum (Asus board as my system spec list). will try that when I get home

[ik9000]

Thank you all for your help so far.

I tried enabling spread spectrum. It made no difference sadly.

Tried 3 dif surge protectors. all with same effect. 2 dif brands, (2belkin, 1masterplug) and while the little belkin seemed to give off less noise on the radio, it was still audible.

Tomorrow I will begin unplugging various bits of the machine inside and see what that turns up.

[Kumagoro]

I have come across a power supply which caused interference with the radio before so you might want to borrow one for testing.

Have you tried testing with a battery powered radio, see if you mobile has an fm radio. You will need headphones to act as an antenna for it to work.

[Flash477]

Does the distance between the PC and the radio make any difference?

[big_hairy_rob]

May well be a red herring, but do you have any wireless devices at all? Do you have a new wireless card or anything similar that has wireless settings (including keyboard/mouse and or bluetooth adapter.

[ik9000]

it's not wireless. It's done this in 2 different houses and is definitely to do with either the PC tower (and its innards)

[big_hairy_rob]

Sounds like a right doozy of an issue. I would agree with your origional post and remove/test the psu. If it's not that, then something else is probably not shielded correctly