RFI Folk,
I have a station located at a house I own with my brother out in the
California high desert - its a residential area, but on 2.5 acre lots.
The nearest houses to ours are about 500' away (lots are 300' x
300').
I've had a bunch of noise problems that I have been trying to sort
out. Last summer I contacted Southern California Edison (SCE) who
sent their RFI guy out (Larry Johnson). Larry did a thorough check of
the electrical poles within about 1000' or more of our house and found
7 noise sources that he reported. It took quite awhile for the SCE
crew to come out, but they did in November. Afterwards, the nature of
the noise I was hearing seemed to change, but there was still plenty
of it.
Larry came back out and checked the poles again and reported they were
all clean, leaving me to think it was a problem with one of my close
neighbors, but now I'm not so sure. Let me tell you all about what I
hear and see if you have any thoughts about what I am dealing with.
On my TS480 with the pre-amp on, the noise peaks at about S6 on the
meter to the east. With the preamp off it is s0 with spikes up to
s3-4 every few seconds. It sounds like garden-variety atmospheric
noise but stronger with some sputtering interlaced. The noise is
broad and fairly strong from just south of east, through north to just
south of west. The power lines are closest to my house on the east,
north and west, so it seems like the noise may be propagating over
them.
When I stand at the eastern part of our property with a portal SW
receiver and a loop antenna, I'm not able to hear the noise much at
all, and can't get any direction on it. My Yagi at 65' picks it up
quite well. I have a 40m four square - the noise is clearly stronger
NE and SE than it is NW and SW.
When Larry was out he hooked up his receiver-scope to my antenna - the
goal was to get a picture of the noise to make sure he was chasing the
right one. However, it was never strong enough to show up on his
device.
I've done the standard thing of turning everything off in the house to
verify it wasn't coming from my stuff. I do have a problem with my
Internet service, which is wireless - it creates a pretty strong
signal I've tracked down on 6 meters and 15 meters. I've replaced my
Ethernet cable with shielded cable and added ferrites but haven't been
able to solve it. However, the noise I am talking about above is not
the same as I've turned the Internet equipment off while I've been
tracking it down. The network equipment does not seem to cause
problems below 21mhz and only peaks when I point my antennas toward
the house. It also is frequency dependent, peaking every couple of
hundred Khz or so.
Some random questions for you:
* Is it all in my head :-) ? I turn the pre-amp off, and its not bad.
Larry's device couldn't even hear it, nor my portable receiver.
Maybe I should just live with it. (I'm thinking not, but had to ask).
My noise at my home in Irvine is much worse, however, but I gave up
on that years ago (being surrounded by houses on 1/8 acre lots).
* How far might this noise be from the house? Its not bad at all
15meters and up, its mostly a problem 20m and down. Could this be a
half-mile away? A mile? Perhaps I or SCE needs to check poles
further away.
* I have an AR8000 portable receiver and a 4 element 2 meter beam - is
this adequate to check poles out to see if they are noisey? Would it
be better to do it on 220 or 440 (Ive got small beams for those bands
too I could use). Use SSB and the Smeter or AM and audio level?
* Would it be helpful to hear samples? I have some .wav files I could
upload to a web site.
* Ideally, I'd like to hear the noise on my portable receiver with a
loop and track it down starting at my property. Otherwise, I need to
wander around until I hear a noise and hope its the right one. Any
thoughts on this?
* I have a mobile rig in my Ford Expedition and can drive around
looking for noise. However, the Ford has bad ignition noise so I have
to stop and turn off the engine to really hear it. Is it helpful to
use a mobile rig and a vertical whip like this to track down the
noise, or am I better off on foot?
* Does it seem likely the noise is coming from a neighbor's house even
though I can't hear it without my yagi at 65'? My yagi is located on
the east side of the property about 150' from our house and perhaps
300' from the neighbor's.
* Is it useful to listen after a rain storm to see if the noise
changed? The thinking being that if it doesn't change (get weaker)
its more likely to be in a house than a problem on a SCE pole? I
don't recall the noise changing much due to the weather, time of day,
or anything else. Seems to be pretty solid.
Thanks for reading my stream of consciousness post, any thoughts would
be welcome.
Dana K6NR
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