Roger, Looks like you need a new laptop. Take a look on eBay where 
you can find lots of 2nd hand laptops for a few pounds. Even quite 
high end desktops are available for less than £100 ex-business.

Mike
====


On 2 Feb 2018 at 20:24, Roger Lapthorn wrote:

> Yes, basically the noise level drops dramatically when charging the
> internal battery pack. I am sure I can get the external noise floor
> lower. This has got worse in the last few years.
> 
> 73s
> Roger G3XBM
> 
> On 2 February 2018 at 19:53, DL3JJ HOME <[email protected]> wrote:
> 
> > Hallo Roge !
> >
> > Is the noise of your power supply so strong that you use battery ?
> >
> > 73
> > Ralf
> >
> > *From:* Roger Lapthorn <[email protected]>
> > *Sent:* Friday, February 02, 2018 7:53 PM
> > *To:* [email protected] ; [email protected]
> > *Subject:* [english 97%] LF: 136kHz RX
> >
> > After sorting out the issue with my shack PC battery not charging, I
> > am *now *monitoring 136kHz WSPR RX and 136kHz OPERA. The shack PC
> > battery (to reduce noise) should be good until late tonight.
> >
> > I'll probably NOT be looking after about 2300z.
> >
> > Let's hope I spot some tonight.
> >
> > 73s
> > Roger G3XBM
> >
>