Help! Help! Every boombox is in danger zone.

[noddy55]

HI,
Almost all the stations at Medium Wave bands on ANY tuner at my home produces a unbearable noise and makes them unhearable. Only noise can be heard. I dissconected the boombox from mains power supply and get it worked on battery. Noise still persists, the same. However, when there is an electricity failure in our locality, battery operated tuners still gives the noise but at slightly suppressed level. This strange behaviour is true to every tuner at my place irrespective of the model or brand. Also, the same tuner works just fine when i took it away some kilometers far from my place (including MW bands). Only the Medium Wave stations are creating problem. FM and all the Short Wave bands works, just fine. I am very upset about this, because i have shifted to my new house and want to build my own working lab for my electronic experiments and projects. I am sad to believe that none of the tuner will work here on MW bands at my new place. I am sure this is not the electrical power induced noise. Is there a remedy possible? Is there a way or a tool or some circuit design to rectify this at my place here? Why only with all the Medium Wave Bands?

Thanks!

 

[teamstress]

It sounds like electrical interference from high-voltage power lines in your neighborhood.

 

[Strānj-Bōōmbŏks]

HI,
Almost all the stations at Medium Wave bands on ANY tuner at my home produces a unbearable noise and makes them unhearable. Only noise can be heard. I dissconected the boombox from mains power supply and get it worked on battery. Noise still persists, the same. However, when there is an electricity failure in our locality, battery operated tuners still gives the noise but at slightly suppressed level. This strange behaviour is true to every tuner at my place irrespective of the model or brand. Also, the same tuner works just fine when i took it away some kilometers far from my place (including MW bands). Only the Medium Wave stations are creating problem. FM and all the Short Wave bands works, just fine. I am very upset about this, because i have shifted to my new house and want to build my own working lab for my electronic experiments and projects. I am sad to believe that none of the tuner will work here on MW bands at my new place. I am sure this is not the electrical power induced noise. Is there a remedy possible? Is there a way or a tool or some circuit design to rectify this at my place here? Why only with all the Medium Wave Bands?

Thanks!

HOLA noddy55!!!
Welcome to Boomboxery, the World's Best Boombox Site!!!
Maybe you wanna hit Superduper with a PM??? (private message)

 

[2steppa]

ADSL/Broadband routers can cause significant interference to MW - just a thought........

 

[Superduper]

There are several reasons that this could be happening but none of the reasons will make you very happy. Suffice to say that if your general area is suffering from interference on your AM bands, that unless it only occurs inside your home and not outside, that the solution is likely beyond your control. The issue could be as simple as poor grounding in your home electrical system, it could be your refrigerator or flourescent lamps emitting this noise. It could be a poorly designed switching/digital power supply plugged into the mains (the Coby HD650 HD radio comes with a cheapo made in China power supply that when plugged in, makes it impossible for any AM receiver in the vicinity to receive). You can confirm if the issue is with your home wiring by switching off the electricity to the entire house and try your radio with batteries. However, if as I suspect, the issue persists, then it probably has to do with either the electrical power distribution system of your electricity provider or nearby homes/factories/stores that are using equipment that generates excessive noise.

This absolutely IS electrical noise interference. I have it in some areas near my home as well. I can witness it when I drive away from my home. There is an area about 1/2 square miles where AM is virtually useless whenever I drive pass that location. It is much worse when the weather is wet.

 

[noddy55]

Thanks for the reply superduper and all of you,others.

I think this is something to do with the phenomena known as : "Radiative common impedance coupling noise".
The disturbance is not throught the electricity wire. It is radiatively induced inside the radio at AM frequency bands.
Just check out this: Play some cassette inside your boombox and give a call to someone at your cellphone near to the playing boombox. You will hear the noise out of your boombox, for the moment the cellphone is dialling out the number and until the call is connected. You don't even need to turn on the tuner for this. Noise will be radiatively coupled inside the boombox circuit.
I wonder if there is any way to overcome this and protect the radio from such Interference? May be some proper and tight sheilding of the tuner circuit could help out? I will appreciate other opinions as well, however.

Thanks.

 

[Superduper]

Already told you... your receiver is working fine. Almost every member here has AM radio someplace in their home, and cell phones are so plentiful here that it's impossible NOT to be exposed to it's radiation. Yet, our AM radios still play. Furthermore, yes, cell phones emit radiowaves.. Lots of it, starting at the 800mhz bands which are now up to 3 or 4 ghz -- microwave regions. But the interference you speak of from cell phones only occurs when a cell phone is right next to the radio. Bring it a couple feet away and the noise is no longer an issue. If you suspect that such common electrical devices are the culprit, they must be somehow connected to a 50kw transmitter then, in order to overcome every radio inside your home and for miles and miles around. In that case, forget about shielding your radios.... you should probably shield your balls instead and maybe wrap tin foil around your head.

You probably misunderstood. Nobody here has suggested that the interference you are hearing is from electrical wire. Every electrical device generates electrical noise. Whether EMI, RFI, whatever. Wires act as antennas and will radiate the "noise." What do you think your AM radio is? It's a RECEIVER and it's sole purpose is to receive electrical signals, even if it's traveling through the atmosphere and not through electrical wire. It does not differentiate between intended signals and noise -- it receives them all as long as the emissions are within the frequency range that radio is intended to receive. The purpose of the previous suggestion to turn off the electricity to your home as a "test" is not to disconnect a method of direct wire connection from other devices to your radio. Rather it's to see if the electrical devices or the electricity distribution (wiring) system of your home is contributing electrical noise, whether radiated or not.

Is there a way to shield your AM radio in such a way as to prevent all these stray signals from being received by your AM radio? Absolutely. Encase it in metal and shunt the signals to ground. But be prepared for total silence however, since by shielding all the stronger signals from your radio, what do you think will happen to the weaker radio programming signals? An easier solution would be to turn off you radio. Then you'll get the same result.... total silence and you won't even waste any electricity in the process.

Sorry for the direct remarks but the truth is not always easy to hear. Since receiving AM programming was so important for you before you moved to that location, I would have thought that you would've brought a radio with you before you committed to the space, to confirm that reception in the area is as you like. If you want to delve into the science of precision radio listening, and all the ways to fine tune your "AM" radio (which the guys on boombox forums are not going to care about), I suggest you participate and discuss this same subject with the group of people who are always trying to extract the smallest signal from the skys.... the Amatuer Ham Radio and DX'ing enthusiasts. Perhaps it's possible they will lend you their $75,000 frequency spectrum analyzers, and after ascertaining the offending freqencies, help you devise a filter and retrofit your $3.99 A.M. radio so you can receive better. But I suspect that it might be far easier to just see if the radio stations you wish to listen to has streaming internet programming. Or maybe move to a better receiving location.

 

[maxhifi]

I have the same problem with AM radio reception in my house, and have tracked down several culprits.

1. All switch mode power supplies - i.e. cell phone chargers, laptop power supplies, and power supplies for computer equipment are highly suspect. The Nokia band charger for my phone is the worst, followed by the power supply for my Compaq laptop. With those two operating it kills AM radio AND SW reception for a radius of about 6 feet. A cheap generic Made in China laptop power supply I bought on eBay is so bad it kills reception on the entire main floor of my house! Tracking down the problem may take a lot of effort here, and may be impossible if it's in someone else's house.

2. Electric motors or engine ignition systems nearby. If there's sparks happening in the brushes of a motor, or in a gasoline powered engine, and they're not being suppressed, it can interfere with AM radio.

The way out of this is to have a directional antenna, such as a loop, and point it directly at the transmitter, then connect it to the receiver with shielded cable. When I lived in a high rise apartment, the problem was so bad I pretty much gave up on AM radio reception, there was no way to disconnect all the equipment my neighbors had polluting the airwaves. Good thing is AM radio is becoming less and less relevant as it becomes harder to receive, so I'm not very worried.

 

[Fatdog]

1. All switch mode power supplies - i.e. cell phone chargers, laptop power supplies, and power supplies for computer equipment are highly suspect. The Nokia band charger for my phone is the worst, followed by the power supply for my Compaq laptop. With those two operating it kills AM radio AND SW reception for a radius of about 6 feet. A cheap generic Made in China laptop power supply I bought on eBay is so bad it kills reception on the entire main floor of my house! Tracking down the problem may take a lot of effort here, and may be impossible if it's in someone else's house.

2. Electric motors or engine ignition systems nearby. If there's sparks happening in the brushes of a motor, or in a gasoline powered engine, and they're not being suppressed, it can interfere with AM radio.

That's very interesting. It kind of makes you wonder what all this is actually doing to us.

 

[Reli]

That's very interesting. It kind of makes you wonder what all this is actually doing to us.

I wouldn't be surprised if the increasing amount of wireless we're bombarded with will affect our species over the long run.

 

[maxhifi]

1. All switch mode power supplies - i.e. cell phone chargers, laptop power supplies, and power supplies for computer equipment are highly suspect. The Nokia band charger for my phone is the worst, followed by the power supply for my Compaq laptop. With those two operating it kills AM radio AND SW reception for a radius of about 6 feet. A cheap generic Made in China laptop power supply I bought on eBay is so bad it kills reception on the entire main floor of my house! Tracking down the problem may take a lot of effort here, and may be impossible if it's in someone else's house.

2. Electric motors or engine ignition systems nearby. If there's sparks happening in the brushes of a motor, or in a gasoline powered engine, and they're not being suppressed, it can interfere with AM radio.

That's very interesting. It kind of makes you wonder what all this is actually doing to us.

I personally don't worry about the effect of switch mode power supplies on human health. The power levels involved are very small - it's just that AM radios are extremely sensitive and amplitude modulation in general is not very well equipped to deal with interference. Living under a high tension power line isn't something I'd want to do though!

Another place to look is dimmer switches for incandescent lights. These guys work with an SCR, simply by chopping part of the AC waveform - the switching transient is steep, and creates all sorts of RF harmonics, which are then nicely radiated all over the house by unshielded AC wiring. This sort of interference could also be coming from a neighboring house or apartment.

I get my fill of AM radio while driving around in my old 1969 Ford, which has the original AM only radio.

 

[maxhifi]

That's very interesting. It kind of makes you wonder what all this is actually doing to us.

I wouldn't be surprised if the increasing amount of wireless we're bombarded with will affect our species over the long run.

Just remember that RF intensity decays with the square of distance from the source. So if you're twice as far away, it's 4 times less powerful, or if you're 10 times as far away, it's 100 times less powerful. It's a case against cell phones, or hanging out in front of microwave antennas, but they jury is still out if cell phones are even responsible for heath problems.

I'd be far more worried about the amount of processed food we are eating, the amount of pollution in our environment, or even driving a car with old tires than the damage done by ambient levels of RF in a normal city location.

 

[im_alan_partridge]

AM radio is awful where i live, ive always put it down to being so close to an airport.
Its kind of ironic that ive got nearly 30 boomboxes but when i want to listen to sports radio stations i have to whip out my trusty digital radio