On Sat, 07 Jan 2012 14:51:23 -0800, Jeff Liebermann
wrote:

On Sat, 07 Jan 2012 14:39:02 -0700, wrote:

One thing that strikes me about this is the random (erratic?) nature
of this interference, varying both in time and duration. To me, that
rules out many devices - common home appliances, factory equipment,
radio transmitters, etc. One thing that does operate on a similar
pattern is a telephone. Is it possibly a cordless telephone operating
on an oddball frequency?

Think about something run by a thermostat, low control switch, or
motion detector. They tend to cycle erratically. Things like a
furnace,

The furnace would correspond to the end of the night, and the
beginning of the morning, which are common times for this. . At the
end of the night, it's cold for the night thermostat setting, and at
the beginning of the morning, it has to get hotter yet.

In some ways my neighbors are very friendly. Most will answer the
door at 9PM. OTOH, when I asked a couple to see how their new furnace
was installed, they looked at me strange.

I wouldn't have nerve enough, as someone suggested, to ask one to turn
off all his power, certainly not unless I had narrowed it down to his
house.

electric heater, water pressure boost pump, pool heater,
demand water heater, sump pump, etc.

Definitely does this even when there hasn't been any rain. I'm
literally the lowest house in the n'hood**, and would have heard my
sump pump when I was hearing the basement radio make the noise.

**And the way it works out, it's 200 yards or more to any house
outside the n'hood, all of which are also higher than I am. .

There are also some uncommon
devices that cycle. Negative ion generator, parking lot light
controller, external HDD or NAS boxes, motion detector operated
devices, iPhone background sync, etc.

Dang, I only rejected one from your whole list.

However, I've been fooled before with this pattern. I was looking for
such things, only to discover that the interference was coming from a
microwave oven at a local eatery. During lunch, the microwave ovens
were in use almost constantly. At other times, a minute or so at a
time. Kinda sounds like the original description.

Maybe I should go look for lights on when it does this in the middle
of the night. That's one thing I might do.

Dumb story:

There are no dumb questions or dumb stories. Only dumb people.

:~) Oops, I shouldn't bite the hand that feeds me. :~)

Many years ago, I had a very difficult time trying to
find the source of short bursts of RFI. I tried for days and failed.
Oddly, the interference seemed wide spread and appeared almost
everywhere that I was sniffing. Eventually, the gears that drive my
brain engaged and I discovered that the Motorola Bravo pager that I
was carrying at the time, was the source. Argh.