I already did the ferrite ring trick. Indeed I've never found this approach
to do very much good at all on noisy psus. I think the sheer wide bandwidth
is the issue. Sometimes you can get away with this for medium wave but not
much else. I was even thinking of perhaps getting a couple of those power
bank batteries as when not actually attached to a charger, they would or
should be completely clean and last for an age on the small loads of the
gizmos I want to power, but then the battery charger for aaa and aa cells
needs to take more current and its bonkers to charge one battery with
another!


Brian
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This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

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"Cursitor Doom" wrote in message
...
On Fri, 18 Dec 2020 21:20:31 -0000, "Brian Gaff \(Sofa\)"
wrote:

OK so I bought my usual wall warts from Amazon, the sort you plug usb
devices in to power them, Unlike usual though these little monsters kick
out
an incredible amount of rfi on frequencies from long wave to almost 24mhz
a
kind of grating sawtooth modulated by 50 hz.
You cannot get inside, but I'd suggest they have no suppression
whatsoever.
They still work of course charge up phones power battery chargers and
power
little gadgets.
So I wonder if Amazon would refund me for them?
This then leaves me with another issue, I need two or maybe three that do
not have this added feature of radio jammer under load. I have tested one
from Apple which came with my phone, (but are no longer supplied with
phones), and there is really no sign of interference, so it is possible.
I guess I could buy from Apple and hope their standards are still high,
or
if anyone knows of a good source for non interfering ones I'm all ears.
Brian

Might be worth winding the leads through a couple of ferrite rings if
you have any lying around, Brian. it will never be as good as proper
proprietory screeening and filtering, but you might reduce the spatter
to an acceptable degree of appalingness.