[RFI] Solar question

[KD7JYK DM09]

> I initially thought that it was a solar panel inverter, but since it 
> occurs when it is dark, I'm thinking that is not quite right. Can 
> someone confirm my thought on this as not being a solar issue?  The only 
> thing that I can think of is if there are battery storage of electricity 
> and they run an inverter at night to power the house.  Thoughts on 
> this?  Would that inverter run during the daytime too?

Just some thoughts...

"It used to be only from 9AM to approximately noon and the rest of the 
day was clear"

Suggests it's controlled, or someone is controlling it.

"Now the problem seems to be happening all day long -- just about 24 
hours a day and it's bad"

Could be something failing, could be something someone is now leaving on.

"s7 on 20m and s3 to 5 on 40m and I suspect that it affects just about 
every other hf band"

A good start, just to get a basic baseline, would be check ever other 
band.  Check "DC to daylight", if you can, for starters.  Every radio, 
every frequency, every mode, every antenna, is a good way to get a 
general idea of the extent of the problem, frequency range, and rule out 
equipment.  If you can, check at higher frequencies, as due to various 
reasons, the higher a frequency the noise is heard on, the closer one 
will be to the source.  I often check up to 1 GHz, which narrows the 
cause down from several square miles on HF (one pole near me covered 18 
square miles with RFI), to a few tens of feet at most when it comes to 
power lines (generally the source, and nothing else).

"I have been through the exercise of turning off the power to my house 
and running the transceiver on battery with no difference in the noise 
level."

Not a bad place to start.  Before that, did you install anything?  If 
you did nothing, changed nothing, no reason to suspect the RFI is yours.

"I initially thought that it was a solar panel inverter, but since it 
occurs when it is dark, I'm thinking that is not quite right. Can 
someone confirm my thought on this as not being a solar issue?"

There are panels, panels with invertors, and invertors.  Panels are 
generally not noisy.  Panels with invertors/"optimizers" will be noisy 
when operational, that is, when sufficient light is hitting them. 
Invertors to convert stored DC power, to household AC power, would 
typically be operational when household AC power is needed, so 
essentially 24/7/365, from the moment a system is put in.  If there was 
a sudden change, and not across all hours, or light-only hours, it's 
probably not solar related.

"Thoughts on this?  Would that inverter run during the daytime too?"

Yes, there's a very good chance a solar powered home uses electricity 
24/7, like a commercially powered home, so the noise would have been 
constant the moment the system was put online.

"My suspicions right now are that it is a solar cell going bad on a 
light pole or cable TV leakage."

Curious how you came to each of these.  A "solar cell" (did you mean 
photocell) on a dusk/dawn light, may produce a buzzing, hissing, 
crackling sound when failing, and would be across a very wide range of 
frequencies, although depending on wiring configuration, could be 
stronger at certain frequencies.  Cable TV leakage, in the past, and 
analog signals, had an odd buzzing sound that changed with the image 
being sent.  It's quite unique, and sounds like nothing else.  If you 
have an older TV, and a pocket AM radio, turn on the radio, set it to 
the upper end of the band, crank up the volume, set it on a TV, then 
turn on the TV.  The cable TV leak detectors I've seen use AM, and 
listen at 135MHz.  I don't know what RFI from new digital cable systems 
sounds like, we don't have anything like that around here.

"I have walked around the neighborhood with a portable radio and the 
only place I hear interference coming from is the light pole across the 
street and from the power transformer located two houses away.  My 
thought are that this is just a symptom, but not necessarily the cause. 
Thoughts?"

Is it the exact same sound you hear at home on 20, and 40?  Are you 
checking on the same frequencies, and same modes as what you hear at home?

"I've contacted the electric utility company and asked for their help"

It is a 60, or 120 Hz AC line noise/arcing that you are hearing isolted 
to only their equipment?  They are good to call when it has been 
narrowed down to a good 98-100% that it's related to their equipment, 
but not for general RFI, as most people live in a self-induced RFI 
cesspool.  Any other operators in the are that can help you track down 
what you are hearing?  As for power lines, most are bad, in most places, 
so you can get a feel for this, and rule in/out, compared to what you 
are hearing, and may hear power related issues, by driving around with 
am AM broadcast band receiver.  Turn on your radio, crank up the volume, 
drive up and down a few streets, I imagine you'll get noise from a LOT 
of poles, and hardware, most of it sounding the same, since the driving 
source is the same.  Compare that to what you are hearing.

How about the tons of RFI generating electronic christmas garbage that 
goes up this time of year?

Kurt