[R-390] Computer RFI and R390s

[Jim M.]

Switching to a laptop might help.  Modern laptops tend to use low
voltage logic (3 volt) which may naturally radiate less.  Also, the LCD
screens would tend to radiate less I would guess.  If you use a "build
it yourself" computer or something assembled by a local shop from
generic parts, you also run the risk of more interference.  Computers
sold by name brands like Dell, HP, etc. are required to meet FCC
certification for RFI.  Something assembled at the local hacker shop may
or may not meet certification.  Otherwise, all the suggestions about
ferrite cores on all wires into and out of the computer are good ones. 
And distancing the antenna from the operating area as much as possible. 
An antenna in the attick just above the shack or in the same room is not
good.  

Richard Biddle wrote:
> 
> If you are connecting the R-390 to the computer audio card, you may also
> want to try a 600ohm/600ohm isolation transformer in the audio line.  I
> had a ground loop problem that cleared right up when I did this.  I also
> put a Topaz line isolation transformer on the primary of the radio
> before the variac.
> 
> >How do you guys keep out computer hash from your listening/receiving?
> >Turning the computer off isn't viable, since one of the programs I use
> is a
> >RTTY program.
> 
> 73 de Richard W5SRB
> 
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