[OFARC] Checking out RFI problems

[Ralph]

There was some discussion at Field Day about noise (radio frequency 
interference) at some of our member's homes.

Here are steps to try before calling your power distributor.
These steps will give clues about the source of the noise

  * make notes of when the noise happens or changes (rain, dry, hot,
    cold, night, day, etc)
  * disconnect antenna (noise may be in the receiver )
  * run your radio on battery power (noise could be in the power supply
    or power mains)
  * shut off all commercial power & run on battery  (noise may be coming
    from your house)


_If the noise is your radio power supply_, try adding chokes to the 
power cord and radio power wires.
A filter capacitor may help too.
If it is noisy power supply, I suggest you talk with ARRL lab, the 
manufacturer, or some one better at this than I am.
Or just replace the darn thing.

_If the noise is in your house_, you can try to find the source by 
shutting off one breaker at a time to isolate the circuit.
Once you find the circuit, go through and unplug each item on that 
circuit to see what it may be.
If you identify a noisy wall-wart power supply ... replace it
For a Larger appliance ...put  a coil in the power chord or add ferrite 
chokes on the power chord (or do both).
Adding a choke on the power cord of your radio power supply may help too.
Some television sets are noisy due to the internal design.
Sometimes a new internal power supply board will help.
Or _unplug the noisy item when you are on the radio._

_If it seems like the noise is coming from outside_ your house contact 
the local power distribution company RFI team.
Remember, many of the power companies provide electricity but do NOT own 
the wires and distribution network.
CenterPoint energy owns the wires and distribution for most of SE Texas.
That RFI team contact is... *jeff.hoke at centerpointenergy.com
*
Jeff helped resolve RFI noise at my home.  He used an advanced spectrum 
analyzer and direction finding equipment to isolate the source as a 
nearby house.
I then worked with my neighbor to find the problem (a bad cell phone 
charger and a bad computer power supply).  My noise on 20M & 40M went 
from s9+20 to s5.
(your results may vary!!)

Good Luck ...

Ralph
KE5HDF*
*
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