Did I damage my receiver?

[JonN]

Hello. Ever since I was playing around with my portable today and I accidentally hit a ceiling lamp (metal..) with the telescopic antenna I've been hearing a "buzzing" sound on my portable. No matter what I do it doesn't go away, there's this "buzz buzz buzz buzz" sound. The radio still works, I can hear signals just fine but I don't want this buzzing sound. I hope I didn't damage it. I think I have hit the ceiling lamp before without it becoming problematic.

Also, could it be external noise? It hasn't occurred before.But ever since I did this it's been happening.

So, any idea on what I should do. Can I do anything?

Advice appreciated.

(I searched the forum but didn't find any relevant topics)

 

[jonwienke]

Take the radio somewhere else, like a different county. Does the noise persist? Is the noise present on all frequencies?

 

[JonN]

Apparently I spoke too soon, but I'll have to see how tomorrow looks. The noise seems to have gone, and reception capability is as it should. Not sure why it appeared. It did seem to be on all frequencies, but not mediumwave, only SW. I tried, 3mhz, 7, 14 and 27 mhz. But a new question, can something like this damage a radio? I'm fairly new to shortwave radios.

 

[ka3jjz]

It is possible but if the radio still plays, then that's not the issue here.

Turn the light you struck off - does the buzzing go away? If so you may have damaged some sort of shield on the light

Even taking the radio outside would suggest that it's something indoors that's causing your problem...Mike

 

[JonN]

I think it's not the lighting (it was during the day, we do not have lights on during the day) I hit the metal on the ceiling lamp (as you know metal affects the antenna). And after that it behaved like this. And I don't believe our lights cause much RFI, they're not LED or any other modern lihgtings. But I do have an LED lamp on my desk that causes a great deal of RFI, so I don't use it, heh.

But thanks for the advise. But I have to go now, I have an exam tomorrow at school. I'll look into it more tomorrow.

 

[trap5858]

Does that lamp have a dimmer? They are often the cause of noise.

 

[JonN]

Nope, no such thing. We use the same kind of light bulbs (good old, standard lights) across our home, and I can keep my lights on in my room without much difference. We don't use "energy efficient" lights (except one at the basement, and it's not on every day either) or any other modern lights.

I should add that the noise wasn't constant. It was in "pulses", not like "buuuuuuuzzzzzzzzzzzzzz......". But instead, like I pointed out earlier, in pulses.

 

[Boombox]

It might have been a coincidental noise that appeared some time after you accidentally hit the light with the whip antenna. From what you're describing, it sounds like a type of RFI. Like maybe a plasma TV, which put out horrid buzzing (and other) noises throughout the HF spectrum.

Did someone switch something on in the house about the time your whip antenna touched the ceiling light?

Switching power supplies put out noises, too -- and so will cell phones and tablet computers (the touch screen on my tablet will put hash out on my SW and MW radios if it's close enough to them). Some washing machines and other devices put out all sorts of weird alien sounds.

And don't forget outdoor powerlines. Sometimes they can start putting out intermittent buzzing sounds out of nowhere, and then stop -- maybe a minute, maybe half an hour later.

Noise from RFI sources won't damage a radio. Things like static electricity can damage some radios. And other more obvious things like lightning strikes will take out a radio.

Glad to hear your radio's o.k. What radio are you using, anyway?

 

[JonN]

Hi there. We do not have plasma TVs in our homes. Just an old CRT wide screen one. But I believe our neighbor does and they're very close by. And I can sometimes see through their windows when they're watching TV in the eavnings. But I do not believe it was on during that time. And we do not have power lines either, not that I know of. How far does RFI from powerlines extend anyway? We only have street lights that's fairly close by.

And I was alone during the day when it happened. So no one else was at home. And I didn't switch anything on, lights are off during the day. And there are no tablets in use in our home either, nor do I have one. But my mom does have one, but it's seldom used. I haven't experienced any RFI from washing machines yet, but I haven't done any SWL when it is on. And we only use it once or twice a month or so.

I'm using a Sony ICF-SW7600GR. The tags give you a hint, heh. This is a mystery indeed, as I think I've hit the ceiling lamp before without any incident. I'm clueless, really.

 

[Boombox]

Hi Jon,
When I mentioned "powerlines" I didn't mean the high voltage ones, I meant the regular kind you see in the average neighborhood, AC power lines strung between telephone poles.

Maybe in your neighborhood the power lines are underground. If so, you have less of a chance of them causing RFI. But if they're strung on poles, and there are transformers on telephone poles, they can cause RFI, and it can radiate down the wires (which act like RFI antennas) and wreak all sorts of havoc on SW and MW. A lot of times it's sporadic. Will start and then stop.

RE: washing machines: the ones I have encountered that cause RFI are the brand new electronically controlled ones. A neighbor a block away has one that causes alien sounds. If you or your neighbors have older models be glad for that if you like to listen to SW.

RE: plasma TVs: From my experience they can radiate RFI up to 150 ft. away. I have a neighbor who has two of them. One of their TV's puts out way more hash than the second TV. When they're on, it wipes out numerous frequencies from 7 Mhz up to just below the 21 meter SW broadcast band. It's a harsh digital sounding buzzing.

The pulses you described sound like some sort of electronic gadget (like a switching power supply) or AC power pole hash (which I've often heard in very harsh pulses).

If your RFI problem re-occurs the best thing to do is take the portable radio outside and see if it's coming from inside your house or somewhere else. I was able to ID at least two RFI sources that way (one was the neighbor's washing machine a block away (RFI radiated a couple hundred feet down the power line), the other was a CFL bulb on my front porch that was working fine but started coating the bottom end of the AM band with horrific hash.

Either way, I'm glad to hear your RFI's gone.
Chris
renton481

 

[FKimble]

I would ne concerned about the antenna connection inside the radio. Lots of leverage on a long antenna. The solder may have been broken or cracked where the antenna mounts inside the case. Could cause similar problem.

 

[JonN]

@Boombox I know what you're talking about when you say powerlines, that's why I mentioned there are only streetlights in my area (do they also cause noise? I don't think they would affect me as they're not next to me), there are no poles with wires around. Maybe they're underground. We used to have a telephone pole in our yard way back, like 10 years ago, but it's been removed. There are no powerlines present in our neighborhood. There is only one area where there are powerlines, and that's where we have our summerhouse/cabin we like to travel to during summer. But that's a very quite location, barely any electronics around, only an old CRT TV and the powerlines are like one or two kilometers away. It's my favorite place for SWL /DX .
I've also heard about the trick you can do to hunt down RFI, any old mediumwave portable can do it.

RE RE: washing machines and plasma and LED TVs: I don't think those would affect me as I'm a pretty long distance away from them. And we have an old washing machine. But I would bet there would be RFI if I was next to the living room when my parents are watching TVs, and our neighbors too. I haven't tested that though.

If the noise returns I will try and track it down. Maybe it's a misc. electronic gadget, it's the first time I've encountered it, but the noise seemed to be just as loud no matter where I put my radio, no matter where I tuned, though some frequencies I think were less loud than others.

There is only my brother who has a desktop PC but it doesn't affect me. Btw, when I do SWL in my room I noticed that my laptop radiates RFI even in standby mode? I didn't think it would but maybe it does, as there's still electric currents flowing through it when it's in standby. Of course it's less noise than when it's on.

@FKimble I was thinking about something like that. But the radio still works, and reception isn't any weaker. When I turn on the ceiling lamp there's only a small "crack" sound and that's it.

When writing this post I went to the same place and tuned to 14000 khz, AM mode. And what do you know? RFI! Now there was a kind of "deee-duuuu", "deee-duuuuu". Siren kind of noise. And it was close to my neighbor. /thumbsdown

 

[JonN]

Now I know what that buzz is caused by! It is my mobile phone battery charger...

Today when I plugged the adapter on my mobile phone to charge it and then turned on the radio I noticed "There's that buzz again!". And I started walking around with my radio to find it and I noticed as I walked out of my room it weakened. And then I went to my room, put the radio near my phone and thought "mobile phone?". And immediately as I only touched the wire on the adapter I noticed it affected the radio. Then I unplugged it and it disappeared.

So, case solved.

 

[Boombox]

Glad you found out the interference source.

Sometimes they can be tricky to find. My printer will turn itself on momentarily every now and then and put weird noises all over the 20 meter ham band. I think it's an internal cleaning / maintenance thing it does. Sometimes I just unplug it if I'm not going to use it for a while.

The chargers for my phone and tablet put out some noise, but fortunately not that much. The radio has to be fairly close to them for them to be affected.

 

[a417]

I was thinking he might have had one of those impedance switched lamps that you touch to turn on...then I read it was a ceiling lamp, which would be foolish to think he would jump each time to turn it on and off. ha