[Elecraft] [K2] : Laptop UPS

[WILLIS COOKE]

Well I didn't plug it into my K3 with the transformer
isolation because my K3 is in its gestation period and
I am waiting for delivery.  But, I don't think that it
would have avoided the problem.  I was using
transformer isolation with a Rascal Interface.  The
hum came through the push to talk ground circuit.  One
of my friends had to replace the transistor PTT
interface with an Opto Isolator to eliminate his
ground loop problem.  I have a separate power feed for
my radio equipment that comes from a box at my meter
loop and quite different ground length from the house
wiring.  You need your computer fed from the same
power source as the radio equipment even if you have a
K3.

--- Brett Howard <brett at livecomputers.com> wrote:

> This is why we transformer isolate our audio. 
> If/when you get a K3
> you'll have this feature built right into the rig. 
> For me I just built
> a cable for the PSK/RTTY and what not and put
> transformers in a box in
> the middle of the cable.
> 
> 
> On Sun, 2008-03-16 at 05:57 -0700, WILLIS COOKE
> wrote:
> 
> > I don't know if it applies to your situation or
> not
> > Raymond, but I had a lot of hum on when I
> connected my
> > 110V Lap top to my TS-850 for PSK-31.  I had the
> > charger plugged into a house circuit and my radio
> > equipment plugged into a separate circuit for the
> > radio station.  When I moved the charger plug to
> the
> > radio circuit the hum went away.
> > 
> > --- Raymond METZGER <ray78crespus at orange.fr>
> wrote:
> > 
> > > Hi Elecrafters,
> > > 
> > >  
> > > 
> > > I am interested to know what solution can be
> used to
> > > avoid the noise
> > > generated by the 220 V AC (OEM) UPS of my recent
> > > Dell Latitude Laptop.
> > > 
> > > For the time being, I can only use the laptop
> with
> > > my K2/100 if the laptop
> > > is powered by its internal battery.
> > > 
> > >  
> > > 
> > > Raymond METZGER
> > > 
> > > F4FNT
> > > 
> > > K2 5,636 - K3 expected at month end (ordered 8
> > > September, "Katiegram"
> > > received last Friday)
> > > 
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> > 
> > Willis 'Cookie' Cooke 
> > K5EWJ
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Willis 'Cookie' Cooke 
K5EWJ