AM Interference

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timmer

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Dec 11, 2003
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Springfield, Il
I have a terrible problem with interference on the lower am band. From about 900 khz and lower it is so bad that I cannot pick up any stations, except for one that is only 20 miles away, and even that one has static in the background. Is there any way to figure out what is causing this, and is there any way to get rid of it? I live near some power lines but a friend of mine across town does also and he doesn't have this problem at all. Thanks for any help/suggestions.
 

specman

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Nov 1, 2005
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Hi Tim,

This can be a very frustrating situation, and in the end you may not be able to do anything about it. You didn't mention what kind of radio you're using, however I'll assume it's something decent. Although the nearby powerlines may be the cause of your problems, there might be a few things you can do to rule out other possibilities too.

1. I'm assuming you can power your radio from batteries; do you get the noise when the unit is powered this way instead of being plugged in? Does your vehicle also get the same noise (both running and when engine is off)? Car radios also generally have better shielding so this test might be quite telling if the offending signal is coming in via the antenna or by another means on your other set.

2. This requires some work, but you can rule out something in your home by turning off the power at the mains. Keep in mind that you'll affect a bunch of systems in your home and that clocks etc. will need to be reset afterwards. Check your radio again with the power in your home off. Sometimes the culprit is right under your roof...

3. Take a drive around your neighborhood while listening to AM and see if the problem is widespread around your area or localized near your home; again the problem might be a bit more local than the power-lines.

4. Contact the stations directly and ask them if they have any reports of similar interference for your area.

If it looks like the problem is indeed widespread for your area (and out of your control) then you'll be limited in what you can do, however you may have some luck using an antenna with some directional properties to it such as a loop. This can be rotated to "null" out the offending noise in some cases; of course this will only be of use if the stations you want to listen to are located accordingly.
 

k9rzz

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Dec 12, 2005
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Milwaukee, WI
It's impossible to give a decent solution without knowing more details.

What kind of radio is this that you're using?

So, you're trying to hear stations in the AM band, but all you hear is noise?? Do you mean that the 'noise' is covering up the stations you're trying to hear, or that there are no stations ... just hiss??

John K9RZZ
 

timmer

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Dec 11, 2003
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264
Location
Springfield, Il
I am using a G.E. "Super radio" with excellent am reception. I listen to it using batteries outside my home and sometimes in the garage. There are several stations in the lower end of the am band that my freind across town (about 10 miles ) can hear fine but I can't because of this terrible static. It is a buzzing type of noise which lessens at about 900 khz and disappears at 1000 khz or so. There is a station in St.Louis (550 am) that can be heard by most people I know but I can't hear it or any other stations in the lower end of the am band at my home. I will try and see if I can recieve them on my car radio and see if the static is on there. I am located near the Springfield Illinois power plant, (about 3 or 4 miles from my home) don't know if that could be it or not. Thanks to both of you for your help and suggestions.
 

gcgrotz

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Feb 21, 2006
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Charlottesville
timmer said:
I am using a G.E. "Super radio" with excellent am reception. I listen to it using batteries outside my home and sometimes in the garage. There are several stations in the lower end of the am band that my freind across town (about 10 miles ) can hear fine but I can't because of this terrible static. It is a buzzing type of noise which lessens at about 900 khz and disappears at 1000 khz or so. There is a station in St.Louis (550 am) that can be heard by most people I know but I can't hear it or any other stations in the lower end of the am band at my home. I will try and see if I can recieve them on my car radio and see if the static is on there. I am located near the Springfield Illinois power plant, (about 3 or 4 miles from my home) don't know if that could be it or not. Thanks to both of you for your help and suggestions.
Sounds like flourescent light or a dimmer. I once had an aquarium heater that had arcing in the thermostat. Another frequent culprit is the arc/vapor type streetlights. Go outside at night and see if slowly rotating the radio will null it out, then look in the direction off the ends of the radio for a streetlight.

Try the power down method. Turn off all breakers, including the main. If the noise is still there then it is outside your house. Then turn on the main, then one at a time turn all the other breakers on until the noise returns. Then unplug everything on that circuit until you find it.

Good luck.
 

k9rzz

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Dec 12, 2005
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3,164
Location
Milwaukee, WI
gcgrotz said:
Sounds like flourescent light or a dimmer. I once had an aquarium heater that had arcing in the thermostat. Another frequent culprit is the arc/vapor type streetlights. Go outside at night and see if slowly rotating the radio will null it out, then look in the direction off the ends of the radio for a streetlight.

Try the power down method. Turn off all breakers, including the main. If the noise is still there then it is outside your house. Then turn on the main, then one at a time turn all the other breakers on until the noise returns. Then unplug everything on that circuit until you find it.

Good luck.
I agree 100%. That antenna inside the SRIII will have a null pointing off the sides of the radio. Use that null from several different places around the yard to triangulate the source of your noise. Don't be afraid to take the radio for a walk or along in the car if that helps find the 'offender'.

Tell us what you find and GOOD LUCK!!

John K9RZZ
Milwaukee
 
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