*Lots of Good has come from this discussion on my part. I use a little
Kaito KA-1102 in the bedroom for listening at night. I had noticed a Big
noise level on 80 meters and other Shortwave bands. My Cable Modem and
Router both use Switching Wall Warts. After walking around the house this
morning, and unplugging things one at a time. I was able to get that
Hash/Noise level under control. It seems that the PSU for the Cable Modem
and Router were keeping me from listening in comfort in our bedroom. My
guess is that while no difference seems to have been made on my HF Station.
I am sure that the noise being generated in these 2 offenders had to be
adding some hash to my Paragon's Receiver. Digging in the junk box, found
me a couple of Wall Warts that did not cause Havoc in my Itty Bitty Chinese
radio in the bedroom. Thanks Guys !!! Another problem solved just by
reading the Ten Tec Reflector................ The Kaito is short on
selectivity but, the sensitivity is pretty good. Now we can listen to the
Early Morning Tennessee Phone Net and be LAZY............A Special 73 to
Bob/K4TAX*
*
73 de Wade/KJ4WS*
On Sat, Sep 8, 2012 at 7:01 PM, Robert Mcgraw <rmcgraw@blomand.net> wrote:
> I solved most all of my noise problems by replacing all of the WALL WARTS
> with a common supply. Hence, the switchers used for my HF station have
> been confirmed as quiet RF wise. They have temp controlled fans that run
> at variable speeds as necessary depending on load and duty cycle of the
> load.
>
> I added a good CORCOM filter to the distribution strip for the TV,
> surround system, DVR, Sat receiver and such. That took the noise down a
> couple of notches more.
>
> I've not had any issues with the CFL's but I don't use the "dimmable"
> type either.
>
> 73
> Bob, K4TAX
>
>
>
>
>
> >>
> >> Sorry to drag this out but its a problem. Noise generated by switching
> >> supplies... I used the TenTec switcher that came with the Orion and it
> >> was clean. The build in switcher in my Icom 775 is also very clean.
> >> They are good design. But go buy a network router or switch, or have a
> >> cable box installed in your house, or even in your neighbors house, and
> >> you may get a lot of noise across the HF spectrum, with strong warbly
> >> carriers at regular intervals. The switching supplies are basically an
> >> oscillator that drives the power devices to produce the output voltage.
> >> Harmonics of that oscillator cover the spectrum. Wall warts are
> >> terrible sources, such as those used to power routers or cable boxes.
> >> I had to replace the wall wart on my router with a traditional DC
> >> supply to clean up one problem, but there are many other oriental wall
> >> warts elsewhere in the house, all creating hash. I have HF mobile and I
> >> can cruise the neighborhood and hear them as strong signals everywhere.
> > Nuff said. 73 Jim N4BE
> > _______________________________________________
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> >
>
>
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