Buzz From Monitor

[KB1TPX]

How can I get rid of the buzz in my rig, that I get from my computer monitor?
I see in photos of many shacks, where operators have thier computer right on the same desk with thier radios. Mine is on the other side of the room and plugged into a separate outlet, and I still get a heck of a buzz when the monitor is on. I tried reversing the polarity, like one would do with a guitar amp, or other audio equipment, but that didn't work.
Should I just go to Radio Shank and get a TVI filter or something? I'm running a low pass filter to help prevent interference when I transmit, but this problem is the opposite.
Bzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz:headbang

 

[Moleculo]

That sounds like a ground hum to me. It may be a separate outlet, but it's probably on the same circuit. To test this, you can run an extension cord from your computer/monitor to an outlet that you know is on another circuit and see if it's gone.

Another possibility is that it really is the monitor. Is it a CRT monitor, or a newer LCD?

 

[secret squirrel]

I do computer repair work. I have my radios in the same room at my repair work. I have the room set up with multiple outlets on separate circuits. No problem with feedback on PC equipment.

 

[Captain Kilowatt]

You could wrap the entire monitor in aluminum foil and ground it but that would make it difficult to see the screen.

Some monitors are really bad for noise while others are really good. My old CRT type NEC monitor was one of the good ones for noise.The Compac ones at work were a wideband DC-daylight RF emitter.:headbang My current LCD monitor is a non-issue when it comes to RFI.

 

[KB1TPX]

That sounds like a ground hum to me. It may be a separate outlet, but it's probably on the same circuit. To test this, you can run an extension cord from your computer/monitor to an outlet that you know is on another circuit and see if it's gone.

Another possibility is that it really is the monitor. Is it a CRT monitor, or a newer LCD?

It's an older NEC AccuSync 751.

 

[hookedon6]

1 try changing the resolution
2 install toroids on all power cables

 

[Moleculo]

A long time ago I had an NEC CRT monitor that gave off a bunch of RFI. Lots of toroids on the power cables is about all you can try. You can add some on the VGA cable also. It's probably not going to solve it though if it's really coming from the monitor. It might be time to consider an LCD...the prices have come way down.

 

[KB1TPX]

A long time ago I had an NEC CRT monitor that gave off a bunch of RFI. Lots of toroids on the power cables is about all you can try. You can add some on the VGA cable also. It's probably not going to solve it though if it's really coming from the monitor. It might be time to consider an LCD...the prices have come way down.

Funny thing is, I had a Dell flat screen and it crapped out on me, so I aquired a used NEC from work for nothing, nice monitor, except for the bulky size and of course the hum. Just thought there was a cheap, easy fix.
Thanks for all of the tips guys.

 

[PickupMan]

i had the same problem a week ago.. all i did is ground my radio to my meter then sent my ground outside to grounding rod. cleaned it right up....

 

[Sonwatcher]

I found the answer to this by experimenting. The noise can be eliminated by changing the hz refresh rate. I have had constant noise on 38lsb. I would turn off the monitor and it would go away. I went into "display" in the control panel and clicked on "settings" at the top. Then clicked on "advanced" at the bottom.
Click the Graphics Media Acc. Driver tab at the top.

I then changed my refresh rate of the Monitor from 60hz to 75 and walla ! Noise gone !

If you have the problem of monitor noise coming over your radio give it a try !

 

[cominatyalive]

Sonwatcher is on to something. I also changed my refresh rate to 75 hz, but that was before I hooked up my CB. I can see how that works, However, I still have this horrible, crackling 60 hz hum coming from my Cobra radios, but my flat screen LCD monitor 75hz or not is not making any noise. However, my son's older 13" monitor he's using, You know, the bulky type monitor, hums like the dickens. You can check the noise by doing this trick. Get a small AM FM transistor radio and put it on AM. Hold it near the suspected culprit and you will hear the noise through the radio. Good luck, I've got a hum problem of my own to try to solve. Good luck.

 

[mackmobile43]

Sonwatcher is on to something. I also changed my refresh rate to 75 hz, but that was before I hooked up my CB. I can see how that works, However, I still have this horrible, crackling 60 hz hum coming from my Cobra radios, but my flat screen LCD monitor 75hz or not is not making any noise. However, my son's older 13" monitor he's using, You know, the bulky type monitor, hums like the dickens. You can check the noise by doing this trick. Get a small AM FM transistor radio and put it on AM. Hold it near the suspected culprit and you will hear the noise through the radio. Good luck, I've got a hum problem of my own to try to solve. Good luck.

sounds like your monitors power supply is on the fritz.

 

[Robb]

I have two LCD monitors around my 11m and 2m rigs - and have no problem with them whatsoever.

I worked on a friend's Cobra 2000GTL a little over a month ago, and it had a nasty hum in it. Turns out that whwn I used an external 12v power supply on it, the hum stopped. The problem turned out to be the large can/electrolytic cap in the power supply of the Cobra. It was old and began to have a leakage problem, so it injected 60 cycle/AC hum into the radio. Once the electrolytic cap was replaced, them hum vanished!

I noticed that you have a couple of Cobra radios.
Food for thought...

 

[mackmobile43]

If you'll open up the monitor you'll most likely find the same problem with the caps. there's a few of them in there and the tops will be puffed up and that's a sign of over heating, the power supplies for these devices are just barely up to grade for this use.

What kills these monitors is not utilizing the off feature of windows after the monitor is not used for a certain period of time and powering it down while not in use will extend it's life by years sometimes.

 

[SharpShooter]

I found the answer to this by experimenting. The noise can be eliminated by changing the hz refresh rate. I have had constant noise on 38lsb. I would turn off the monitor and it would go away. I went into "display" in the control panel and clicked on "settings" at the top. Then clicked on "advanced" at the bottom.
Click the Graphics Media Acc. Driver tab at the top.

I then changed my refresh rate of the Monitor from 60hz to 75 and walla ! Noise gone !

If you have the problem of monitor noise coming over your radio give it a try !

Bump for this old thread

I use an old HP computer with dual LCD monitors....for Ham Radio Deluxe and Kenwood's radio control program.( these programs don't need any real horsepower to run )

I " had " a buzz is some areas on some bands.

On some feq's the buzz was 3 to 4 s-units

Adjusted the refresh from 60 to 75 and the buzz is 90% gone !

Thanks for the tip !