It doesn't (all) specifically apply to laptops, but here goes anyways....
It is essential that the PC itself be "bottled up" - make sure all the case
edges are really in contact. In this regard, I buff the edges with a
"scotchbright" pad as it is common to find paint overspray. I also may add
extra scews to hold things together - and this is why I "roll my own" rather
than buy an assembled commercial unit. And while I am on this subject, I cannot
imagine the (recent) cabinets with plastic windows ever meeting any class B
specs. I have also had to modify power supplies and change the AC input
connector to one of the "Corcom" or similar type - some supplies are very poorly
filtered. Finally, I add ferrite suppressors to virtually every line out of the
'puter which usually cleans up things pretty good, though maybe not 100%.
As far as monitors go, CRT units seem to be worse for radiation and the
harmonics can be seen to move by changing the refresh rate, etc. Also, it can
vary with brand and model. One here in the house (on a different 'puter -
upstairs) has to be literally turned off when not in use (appears to be direct
radiation; ferrites don't help). The computer itself is clean (well, at least
on the bands I use). With a little luck, it'll blow up and I have to replace
it. :-) OTOH, I am having zero problems with a Samsung 150S LCD display
located 10' from the radios (closer - ??) here in the shack; I did have problems
with the old CRT monitor. I cannot say that all LCD displays will yield the
same results.
For your laptop problem, I would try ferrites on the cables as a first attempt;
there is often one on the cable, but this is not enough. I would also try to
find the route the RFI is getting into the radio.
Good luck.
73,
Tom - WA2BPE
Deni wrote:
> I'm always intrigued by the photos of other peoples shacks with the PC and
> monitor mounted right in among the radio gear.
>
> I have a conventional tower and CRT monitor which creates nasty QRM in my HF
> receivers, I also have a laptop with TFT screen which is not too bad but
> it's switched mode PSU/Charger is chronic anywhere near my radio.
>
> I'm interested to know how others solve the PC / Radio interface and
> maintain low interference levels.
>
> 73, Deni
> F5VJC, GM3SKN
>
> _______________________________________________
> RFI mailing list
> RFI@contesting.com
> http://lists.contesting.com/mailman/listinfo/rfi
_______________________________________________
RFI mailing list
RFI@contesting.com
http://lists.contesting.com/mailman/listinfo/rfi
|