Interference on Radio when recording to plugged in laptop
 

Mike Chambers wrote:
I have an Eton E5 which I connect to my laptop via the Line Out on the
Eton to the Line In on the laptop.

This works great for recording shortwave broadcasts, but if the laptop
is plugged in, it generates some interference on the radio (only when
they are connected via lineout / in). If I unplug the laptop, there is
no interference.

Does anyone know if there is anything I can do to get rid of the
inteference? I want to set up my machine to record programs overnight,
so I can't leave the laptop unplugged.

mike

http://mesh.typepad.com

I hope I'm not asking the obvious, but are you closing the lid on the
notebook computer? That kills the noise from the LCD and CCFT.

Note that the switching supply puts noise on the power line, which in
turn is picked up by the radio. You can try to put the switcher on it's
own isolation, be it filtered power line strip or perhaps isolation
transformer.

Interference on Radio when recording to plugged in laptop
 

In article ,
John Smith I wrote:

Telamon wrote:
...

In your previous post:
---------------------------------------------------------------------
"I usually don't joke about the subject. The transformer is really no
different than the opto-isolator for DC isolation. One couples primary
and secondary circuits magnetically and the other with photons.

Either one will not be an effective block unless they are designed to
prevent passing common mode RF noise. It takes very little in stray
capacitance or mutual inductance to go around the opto-isolator."

---------------------------------------------------------------------

See the part, "The transformer is really no
different than the opto-isolator for DC isolation. One couples primary
and secondary circuits magnetically and the other with photons."

Why in the hell would we even concern ourselves with dc isolation, it is
rf which is causing the problem ...

Now, see the part, "Either one will not be an effective block unless
they are designed to prevent passing common mode RF noise."

There would be NO coupling, other than a light beam--and I asked you,
are you claiming the rf is traversing the light beam? (and, if so, you
will notice that I implied ONLY AN idiot would site that as being a
problem in this case.)

I can't help you.

Plonk

--
Telamon
Ventura, California