"Ralph Mowery" wrote:
wrote in message
...
I hooked up a switcher to a cb radio, very horrible noise which also
made
the circuitry act funny. With the application of 4 more ferrite
devices, I
got it usable.

Fix your radio.

Nothing wrong with radio. The switcher was not designed for radios.

If the radio won't work with switcher noise it won't work in any noisy
environment, either. If it isn't broken, it's crap.


Some switching supplies generate a lot of noise that is in the radio
frequency area. They will power devices fine, but at the same time if you
want to receive something that some of the RF noise appears on, there will
be a problem. Some of the battery chargers around the house RF generate
noise even when not charging a battery.
Some small fans such as in a computer that work on DC have an internal
switching supply of sorts that can also generate RF noise over a wide
frequency rnge.

I built a lot of stuff for medical research, which is very sensitive to LF
noise, especially 60 Hz. I found most of the switcher supplies from jameco
were great at not producing noise in that area.

On cb I noticed what sounded like a charge and discharge, loud cracking.
Sounded like a power line leak. I went all around house finding strange
places where the noise showed up. Outside the noise was coming from power
lines. Walked up the street 300 feet, the noise was the strongest. Back at
the house I was convinced there was still something in the house. Started
flipping breakers. Found it. but didn't seem logical. My kitchen computer
area had a power strip. Look down at sears lithium power drill charger I
plugged in day before. Pulled plug, got it. The noise was not strong at the
device. I'm still wondering if neighbor has similar device up the street
where it was the strongest.

Greg