Man, been a busy day today.
This is why you want to use a dedicated 115VAC circuit for you ham gear.
I published this about 9 months ago on the Jupiter Yahoo Group, here it is
again!
How AC Noise is Created
Electrical noise is a natural phenomenon. Along with the fundamental 120V
60Hz power, reactive currents are on the service mains neutral and ground.
Reactive currents represent "unused" energy that has been discharged onto
the power lines from the impedance load as the source voltage modulates. Each
piece of connected equipment in your home or office adds to the total reactive
current on the neutral wire, which in turn is connected to the electrical
systemâs ground. The level of these reactive neutral/grounding currents can
be
considerable. In many cases in the past, there have been high enough levels
of reactive currents present in the power to crash data processing systems.
Historical evidence attesting to this fact is overwhelming.
Data processing facilities have long had problems with AC power. Itâs no
wonder that the audio industry is finding out that digital sound reproduction
is
no piece of cake. In other related areas such as digital broadcasting,
malfunctions from poor power often prove to be the "Achilles Heel" of the
system,
particularly where extremely high bit rates and wide bandwidths are used.
Compressed noise can cause real problems.
Electronic power supplies have long been known to create these reactive
currents. In the electrical power industry, an entire segment of that field has
grown up around the study of "power quality." Power quality (PQ) has much to do
with the purity of AC power as it affects the operation of sensitive
electronics.
Aside from reactive currents, there are other PQ issues involved that can
affect equipment performance. Among them is Power Factor. Whenever the true
power used by a load equals something less than the apparent power being
supplied, reactive currents make up the difference.
This ratio between true power and apparent power is called "Power Factor."
Ideally the ratio would be 1:1. However, the presence of reactive current means
that some portion of the power that is present has shifted phase. This is
due to the effect of reactive current from a typical non-linear (impedance)
load. Some of the voltage is lagging 90 degrees from the fundamental voltage
phase. This shift in voltage away from the active current phase means that to
that extent, simply, there is no power present. Voltage and current must be in
phase for power to exist -- for electricity to actively create an effect. Low
power factor means that the efficiency of equipment power supplies will be
affected.
Often studio owners will comment that their equipment sounds better at
night, a symptom of heavy commercial use on the power system during daylight
hours
and an indication of poor power factor.
I got tired of listening to the wifes hair dryer, tired of listening to the
garbage disposal and what other stuff she was turning on upstairs through my
rigs.
Soooo!
What I use to help with these stray reactive currents is an 120VAC Line
Filter Model 473 / 40amp as sold by Array Solutions, cant remember how much it
cost. All of my ham (Orion, TS-950DX and IC-756proll) equipment, 50amp power
supply and 8 pieces of sound reinforcement equipment is running through this
AC
filter from a dedicated 115vac 20amp circuit. The AL-80B is on a dedicated
220vac circuit (shared with the clothes dryer, but never run at the same time).
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