Unwanted Mysterious Radio Signal

Chip Fossa · From: Monson, MA, USA (deceased)

Well, this is really a new one for me. Lately, over the past few days, when I boot-up my pc, and everything settles down and the desktop is there, a very clear radio broadcast comes thru my speakers loud and clear.

And not a nice station either, BS advertising.

This morning it happened, and I had the tv on
and figured maybe it was acting as an antenna and shut it off. The radio transmission stopped, but when I turned the tv back on, the radio did not come back.

Anyone else experience this? And what can be done to get rid of it?

Oh yeah, the tv is brand new and is digital,
and both tv and pc use Comcast Cable.

Thanks all.

Chipper

Joey Ace · From: Hamilton, Ontario, Canada

I suspect it is being picked up by the wiring in you speakers, not the computer.

Computer speakers are often poorly shielded.

Determine if this is the case by disconnecting the speakers and listening with headphones the next time it happens.

Then we'll know which side to troubleshoot.

[This message was edited by Joey Ace on 18 August 2005 at 05:45 AM.]

Jack Stoner · From: Kansas City, MO

If it's RFI and it obviously is, there isn't a lot you can do with many PC speakers. The cabling that connects to the PC is "speaker" wire rather than shielded audio cable and many can't be replaced.

This comes up frequently on the Dell user's support forum when people are near radio stations. It can be RFI (Radio Frequency Interference) that it's picking up or it can be "RFI" that is on the AC power line. You can filter some of it out if it's in the power line but may still never get it all out.

The new TV incident may not really have been the cause.

There are a lot of new "low power" stations coming on the air and one of those may be causing it too. Many of those are not even licensed or the person running them has no idea and all they know is they turn it on and it works - they know nothing about RFI prevention issues.

The first step is to make sure everything you are using with the PC (and anything such as the TV that can potentially generate RFI) is all properly grounded and that your house AC wiring is properly grounded and that all the AC power receptacles are properly grounded. Also make sure all the AC power receptacles are properly "phased" (hot and neutral wiring is correct).

If you are using a power strip for the PC, some of the "plastic" types are not fully shielded. And, you need to verify the power strip is working properly.

Ray Minich · From: Bradford, Pa. Frozen Tundra

I'm reminded of the story that appeared in Uncle Tom's Corner in a mid '60's issue of Electronics Illustrated. A reader wrote that he had built a crystal radio, and that the Voice of America came thru his headphones loud and clear. He then stated that the signal was strong enough to drive a small speaker. Uncle Tom replied that if the reader lived anywhere near VOA's 1 million watt transmitter, the signal should have been strong enough to drive a small car.

John Bresler R.I.P. · From: Thornton, Colorado

I had a problem similar and it about drove me crazy trying to figure out what had happened. In my case, the speaker jack that was plugged into the output jack on my sound card was not completely plugged in and caused the rfi (missing ground). It was plugged in just enough so that I got a clear sound but also picked up a local radio station

Chip Fossa · From: Monson, MA, USA (deceased)

Thanks fellas, for all your tips and anecdotes.

It's exactly 7 years since I got my 1st pc
[Aug.'98] and the speakers and everything has always been located in this very spot.
Unless, as Jack mentioned, some new low-frequency station in the area has popped up, why haven't I received these radio signals in the past?

Joey, I'll give your headphone test a try, the next time this happens.

Jack, I live in an older modified trailer, and the guy who lived here before me was a licensed electrician, and actually rewired the place. I have many, many power strips and extension cords all over the place, and I'm sure 1 or 2 ext. cords may not have the ground prong. Anyway, checking all this polarity and grounding, in my cluttered joint, would be no small task. I'd have to do this in stages, for sure. I do appreciate the advise, no less.

Chipper

Bill Llewellyn · From: San Jose, CA

Colm Chomicky · From: Kansas, (Prairie Village)

There is an radio transmitter tower about 1/2 mile away from my place. I get county music on my telephone.

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