Re: Nightly noise interference

[nobody@xxxxxxxxxxxx (Dave Houston)]

Jim H <jimh@xxxxxxxxxxx> wrote:

>On 11/17/2010 4:33 AM, brucehvn wrote:
>> I have had X10 installed in my house for years.  Within the past
>> couple weeks, I started noticing that at night, a lot of my X10 stuff
>> wasn't working.  I've done some investigation with my ESM-1 meter and
>> have found that one leg of the house is experiencing outrageous noise
>> levels.  The meter shows a steady reading of over 50%.  The other leg
>> is fine.  My front porch light is scheduled to come on around 1/2 hour
>> after sunset and that seems to work most days, but it will never shut
>> off because sometime after that this huge noise starts.  I have a
>> coupler-repeater installed, but the noise is too great and it doesn't
>> help.
>>
>> I don't think this is coming from my house.  Nothing much changes here
>> between night and day except for a few lights, but I'm sure they
>> aren't causing the problem.  I'm guessing it has to be a neighbor,
>> probably close, right?
>>
>> What can I do about this?  I have a Panamax whole house surge
>> suppressor which has not been installed yet.  Would that be able to
>> block noise coming from outside, or do I need some other kind of whole
>> house filter?
>
>Don't be so sure that the problem isn't in your house. You said that the
>last thing that works properly is the lights turning on. Lights can
>cause electrical interference. LED, CFL, and other types of lights can
>be the culprit. Try turning each one off, then see if it improves.
>
>I would think that if it external to your home, it would appear on both
>phases of the power line.
>
>Set up the meter, and watch it to see when exactly the noise begins.
>That may be a good clue to the problem.

I agree that it is likely to be internal. Things like furnace blower motors,
which have been idle during the summer, can be a noise source like this. A
new or failing CFL or anything new with a Switch Mode Power Supply might be
the culprit.