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My computer seems to put out a lot of RFI. I also have a Grandstream VoIP phone that makes my HT go nuts and even affects my mobile radio when I am in my driveway. What can I do to reduce the RFI from my computer and other devices that I am picking up on my radios?

asked Dec 10 '09 at 04:41

KJ4FZA's gravatar image

KJ4FZA
858


Hello:

Well I would make sure that the computer is connected to its own power source. then I would check to see if all the pc cables are good,no cracks etc,make sure that you have a good RF ground.I would try to relocate the computers cables as far away from your rigs power supply,most of the time the pc is causing interference from the its connections and from its power supply being in line or close to the eqpt.you can try some ferrit cores from Amadon Co. T4s I think at 1 1/2ID wrap the pc supply cable threw this core 3/4/5 times this may do the trick if the others did not,there have been a few times that I could not get the interference to stop or attinuated somewhat.Pc noise problems are a Bugger to fix somtimes.I have all my cables from my Accer Aspire 9500 pc 2 ft from my transceivers all gear is connected to a copper groung buss - going to a 10ft copperclad groundrod with less than 1/8th wavelength of solid#2 copper wire going too and from the buss.I was picking up a noise from my pc then I moved the cabeling away from the rigs power supply and cleared it up-no noise fron a pc in 8 yrs.Good Luck

answered Dec 10 '09 at 05:34

K8PG's gravatar image

K8PG
2748

This review of the Grandstream VoIP phone also reports some interference with Radio gear.

review

I am not sure if you have the same model as the reviewer or not.

answered Dec 10 '09 at 06:01

AC0QW's gravatar image

AC0QW ♦♦
322117

That's the exact phone!

(Dec 10 '09 at 12:51) KJ4FZA KJ4FZA's gravatar image

Have you checked that the computer is the problem? Try shutting down the computer and peripherals. Be sure to disconnect all power cords, since many devices nowadays are active even when "off". Follow every cable to/from the computer: network, video, speakers, DSL/modem, etc. Disconnect and/or power off all those devices, and see if they're attached to anything else. If the RFI is gone, leave your radio on and start powering up/connecting individual pieces of the computer one at a time. (The biggest RFI problem I have is my monitor. Unfortunately, it's not so easy to fix, and I can't afford to replace it.)

Some other things to check:

  • Make sure the computer case is RF-tight, all fasteners attached, unused PCI slots covered, etc.
  • Does your monitor cable have chokes? On both ends?
  • Network cable shouldn't be a problem, unless it's damaged or kinked.
  • Are there any other cables? (Besides power, already mentioned in another answer.)

answered Dec 10 '09 at 15:16

N3JIM's gravatar image

N3JIM
2268

One other thing to think about is that an old CRT display seems to cause more noise then a flat panel monitor. As you did not mention the type you had, it might be worth trying a different monitor if you have access to one.

answered Dec 14 '09 at 02:49

KB1QHX's gravatar image

KB1QHX
256

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Asked: Dec 10 '09 at 04:41

Seen: 1,079 times

Last updated: Dec 14 '09 at 02:49

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