CB interfering with speakers on computer

[john-o]

I have a Cobra 29 and lately, when I key up, the speakers on my computer get this humming sound. I'm also getting a lot of white noise on the speaker of my Cobra in the standby mode. Has anyone every experienced this kind of problem with their CB?

 

[FPR1981]

CB is and always has been capable of causing harmful interference to nearby audio equipment. And likewise, audio equipment is capable of causing harmful interference to a nearby CB.

 

[john-o]

I haven't changed anything with my small base station. For years I operated my Cobra 29, from my truck when I retired. The only thing that I can think of is either my antenna cable has a crack in the plastic covering, and has lost its shielding, or the new mic that I bought has some sort defect in its shielding, OR, my ground on the CB and/or antenna is not properly made. If I'm doing this interference on my computer, I can only guess that I might be causing some problem(s) next door to my neighbor's stuff. I'm gong to do some switching around and see if I can isolate my problem. If and when I do, I'll be back to the forum and narrate what I found.
Thank you FPR1981 for your reply.

 

[reedeb]

Simple solution, Turn OFF the speakers.

 

[FPR1981]

I haven't changed anything with my small base station. For years I operated my Cobra 29, from my truck when I retired. The only thing that I can think of is either my antenna cable has a crack in the plastic covering, and has lost its shielding, or the new mic that I bought has some sort defect in its shielding, OR, my ground on the CB and/or antenna is not properly made. If I'm doing this interference on my computer, I can only guess that I might be causing some problem(s) next door to my neighbor's stuff. I'm gong to do some switching around and see if I can isolate my problem. If and when I do, I'll be back to the forum and narrate what I found.
Thank you FPR1981 for your reply.

It's honestly hard to tell. Even the smallest environmental or atmospheric changes can affect things like this. You might ask your neighbors, as a courtesy, if your radio ever interferes with anything in their home. Being a good neighbor is a much better solution than someone *****ing enough to the FCC that you get a knock on your door. It's rare, but it does still happen.

 

[krokus]

I haven't changed anything with my small base station. For years I operated my Cobra 29, from my truck when I retired. The only thing that I can think of is either my antenna cable has a crack in the plastic covering, and has lost its shielding, or the new mic that I bought has some sort defect in its shielding, OR, my ground on the CB and/or antenna is not properly made. If I'm doing this interference on my computer, I can only guess that I might be causing some problem(s) next door to my neighbor's stuff. I'm gong to do some switching around and see if I can isolate my problem. If and when I do, I'll be back to the forum and narrate what I found.
Thank you FPR1981 for your reply.

Corrosion in any part of the system can cause problems. (Antenna mount, coax, power leads, etc.)

Any other nearby metal items too, if there is any corrosion where they touch each other.

 

[n7lrg]

Might try installing a couple of snap-on ferrite toroids to the CB coax or on the speaker leads. Amazon has a variety kit that weren't too expensive. A low-pass filter may help but is sounds like RF overload due to proximity.

 

[WB9YBM]

I have a Cobra 29 and lately, when I key up, the speakers on my computer get this humming sound.Has anyone every experienced this kind of problem with their CB?

I've had something similar happen with both CBs and ham radio equipment--my audio coming out of a neighbors' stereo or TV (even computer) speakers, primarily when the neighbors' equipment is located near the edge of their property closest to my home, and my antenna located near the edge of my property close to the neighbors' home. When equipment and antennas get that close, it happens through no particular fault of the equipment per se'--television sets & stereos, especially the modern ones, are enclosed in cheap plastic cases that provide no shielding nd quite often the cabling connecting speakers to TVs & Stereos are not shielded (to save on manufacturing costs). Typically the problem can get cured with better cables, bypass capacitors at the speaker, ferrite beads, or any combination thereof.

 

[prcguy]

Snap on ferrites should fix it and you need to have at least several turns of wire through them instead of just snapping them over the wire. The RF could be getting in through the power cable or the low level audio input cable or the speaker wires. I would try the power cable first then the low level audio line since they are only one wire to deal with at a time and you might get by with just one ferrite. If that doesn't fix it then try the speaker wires.

Might try installing a couple of snap-on ferrite toroids to the CB coax or on the speaker leads. Amazon has a variety kit that weren't too expensive. A low-pass filter may help but is sounds like RF overload due to proximity.

 

[n7lrg]

Snap on ferrites should fix it and you need to have at least several turns of wire through them instead of just snapping them over the wire. The RF could be getting in through the power cable or the low level audio input cable or the speaker wires. I would try the power cable first then the low level audio line since they are only one wire to deal with at a time and you might get by with just one ferrite. If that doesn't fix it then try the speaker wires.

Agreed, I should have clarified my description of the ones I mentioned. These types are bullet shaped and come in diameters that snap onto the coax. Imagine a hot dog in a bun.

 

[prcguy]

The hot dog buns that just fit the coax and snap on do nothing at HF, absolutely nothing. At VHF a single snap on will do a little and it can be measured but its never enough to reduce or eliminate an RFI problem, you need the right mix and at least three in series at VHF or a single snap on with two to three turns through it is more effective than three or four in series.

For 27MHz you would need a string of beads several feet long to start making a difference or the right number of turns of cable through a large ferrite toroid of the right mix can make a huge difference. I have test setups here to measure the effectiveness of ferrite chokes and its a very specific thing where you are unlikely to reduce RFI using a random ferrite and not knowing how many turns to run through it.

Agreed, I should have clarified my description of the ones I mentioned. These types are bullet shaped and come in diameters that snap onto the coax. Imagine a hot dog in a bun.

 

[slowmover]

The hot dog buns that just fit the coax and snap on do nothing at HF, absolutely nothing. At VHF a single snap on will do a little and it can be measured but its never enough to reduce or eliminate an RFI problem, you need the right mix and at least three in series at VHF or a single snap on with two to three turns through it is more effective than three or four in series.

For 27MHz you would need a string of beads several feet long to start making a difference or the right number of turns of cable through a large ferrite toroid of the right mix can make a huge difference. I have test setups here to measure the effectiveness of ferrite chokes and its a very specific thing where you are unlikely to reduce RFI using a random ferrite and not knowing how many turns to run through it.

PALOMAR ENGINEERS has a website full of Noise Reduction tactics. Plenty to read. (Good place to buy). In the Peterbilt it’s treat each end of every cable/type.

FT240-31 and FT240-61 toroids are a basic part of Radio Kit.

1). I would suspect coax first if it’s more than a few years old. Terminations go, corrosion gets inside, etc. UV can wipe it out. It’s where I’d start.

2). Station ground (gear) is the second, IMO.

3). Household wiring re-radiating.

Common Mode

It would take nice strong beer to appreciate that through which I’ve heard myself hurtling along at 66-mph at o’dark thirty.

.

 

[WA0CBW]

New microphone? Overdriving the audio causing over modulation and splatter?

 

[Jhernan488]

Are you putting out more than the allowed wattage? High power will go through speakers even if they are off.

 

[iMONITOR]

Is this a base CB with an outdoor antenna? Is the antenna/coax/radio properly grounded?

 

[lover156]

I have a Cobra 29 and lately, when I key up, the speakers on my computer get this humming sound. I'm also getting a lot of white noise on the speaker of my Cobra in the standby mode. Has anyone every experienced this kind of problem with their CB?

Yes I used to have that problem on old TVs I still turns my outside lights on if I have the lights on standby. Now I shut the lights off. Rick

 

[press1280]

Way back when I didn't know jack about CBs I had an old Sharp 23 channel set up in my bedroom using a 12v car battery charger and connected to the rooftop TV antenna.
When I used to transmit it would show up (pretty clearly) on the house phone. My dad as a minister would be on the phone all the time and would constantly be yelling at me to get off the radio!

 

[dlwtrunked]

CB is and always has been capable of causing harmful interference to nearby audio equipment. And likewise, audio equipment is capable of causing harmful interference to a nearby CB.

Your 1st sentence "Yes". Your 2nd sentence-I want to say "No" but will back off to "very very very unlikely".

 

[FPR1981]

Your 1st sentence "Yes". Your 2nd sentence-I want to say "No" but will back off to "very very very unlikely".

I'm a working guitarist, and some of my wireless gear has caused RFI type issues to my radios through the years. I promise I didn't pull that out of thin air.

 

[dlwtrunked]

I'm a working guitarist, and some of my wireless gear has caused RFI type issues to my radios through the years. I promise I didn't pull that out of thin air.

I thin o wireless as radio and I do not consider such equipment that purely audio equipment. Neither do I think of noisy wall wart power supplies as audio equipment as their function is not audio. I do believe you but that was more of a radio interference than audio interference.