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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
Marcelo:
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 |
