DX News
Probably the best DX site in the world  
Front page
DX News
Andes DX
DX Lab
In Print
Web Stories

Web Archive
Mail Archive

Search all HCDX
mail since 1995

 About us
About us
Write to us

HCDX mail list

Computers and noise

John T. Wagner, USA:
I am on my third Compaq Presario laptop and have never had any RFI trouble in my RF Shack.
I might add that I have 6 HF receivers and 13 antennas hooked up at all times. No problems.
HCDX mailing list, 6 January 2003

I also have a laptop (Dell) and it doesn't make any interference on the radio as long as I use it with batteries. If I plug the AC cable it generates an extremely strong interference.
However, I can't use the radio with my desktop computer. It generates all sort of interferences, from the monitor, Hard Disk, power supply, everything.
HCDX mailing list, 6 January 2003

Reijo Alapiha, Finland
Use better power supply (AC/DC adapter).
Some switching-mode power supplies generate strong interference.
HCDX mailing list, 16 January 2003

Günter Lorenz, Germany:
I use Dell laptops and experience the same problem. It helps however to plug the laptop power supply into another socket/outlet in the room.
Never plug it in the same connector where the radio is connected!
HCDX mailing list, 16 January 2003

Don Nelson, USA
We've had at least one laptop that was powered by external "brick" power supply that had a similar problem as described by Marcelo.
We've found that putting a a few wraps of the DC side of the power supply through a ferrite core resulted in cleaning up this problem.
HCDX mailing list, 7 January 2003

Chuck Hutton, USA:

I don't know what machines are best/worst, but would not count on any of them to be perfect.
To compensate for the lack of perfection, I always use snap-together style ferrite chokes on all cables coming into and out of the laptop.
Fair-Rite makes a few, and Radio Shack carries one, or a similar product from someone else. We used them in the telecommunications laboratories I have worked in, and they really cutthe noise down.
MW and SW DXíng is another matter and they may not totally solve the problem, but they should be worth a try. I use them at our Grayland DXpeditions and either because of the coax feeds and/or the chokes, I have had no problem with either my 600 MHz or (sometimes) 300 MHz laptops.
Others have had a laptop RFI problem at Grayland but I was not there at the time and don't know what the cause and solution were.
HCDX mailing list, 6 January 2003

Nick Hall-Patch, Canada:

In addition to John Bryant's comments in the HiTeck DX article about not RFI problems with laptops:.
Rremember that at Grayland we use electrically sanitary coax lead-ins for our antennas with separate antenna ground from receiver ground.
A loop antenna next to most laptops will show RFI
HCDX mailing list, 5 January 2003