[VHFcontesting] Re: [DX] RFI/Power line noise problem
dshrader at earthlink.net
Wed Sep 18 17:04:14 EDT 2002
John, Three years ago I had a similar problem.
I would get an intermittent S7 to S9 signal that was very broadbanded. I
'SOLVED' the problem with an ANC 4.
About a year later, after I put up a beam, I located the source. Using
my beam and the AM mode I located the general direction which was South
East of my location. Referring to a Topographic Map I observed a
Shopping Mall about 1 1/2 miles from my QTH.
A trip to the Mall in a friends HF equipped mobile traced the source to
the electrical sub station at the mall. Driving past the
transformer/electrical distribution substation the noise went to 30 over
S9. [AM on 10 meters]
A letter to the mall maintenance office with copies to the electrical
company and the FCC and VOILA! several weeks later no more noise!!
Moral of the story: use a beam and a true AM receiver to locate the
general area of noise. Get a friend or member of the local club with HF
mobile to assist. Once found, go to the maintenance dept. for a
Deacon Dave, W1MCE
With that said I want to advise that some solar induced broadband noise,
particularly during a solar flare, will raise the background noise level
to the S9 level for short periods of time. This noise has no
'directional' characteristics and generally quiets within 10 to 15
minutes. It is followed by loss of propagation on HF.
John Geiger wrote:
> Turning to the reflectors for some help in this
> problem. I seem to have a decent amount of static
> (s5-6) at times on HF (especially 30 meters and below)
> and on 6 meters. I even bought a FT100D to use on the
> reputation of its noise blanker,and the NB does work
> on it at times. Other times it even overcomes the NB.
> I called the local power company who came out to
> check for power line noise-using some equipment that
> received in the VHF range. They found nothing from
> power lines, but did locate 1 house several blocks
> away that was throwing out some static-it isn't this
> house that is affecting me as we tried some tests
> yesterday turning off their power, etc.
> The power companies conclusion is "Sorry, it is not
> our lines, we can do nothing more, good luck." So
> what do I do now? This noise is frustrating at best,
> and really interfering with my receiving at worst. I
> am not ready to conclude that it is not power line
> noise, as it seems to me that most people with line
> noise problems, get them in the lower HF range, not in
> the VHF range like the power companies equipment
> I have tried to locate the offending source in my own
> house, and nothing here seems to be causing it. Cant
> seem to null it out using my miniquad-it seems to be
> coming from all directions and it is worse still on my
> G5RV dipole.
> I do have some noise on 2 meters, not as bad, that is
> coming from the NE-I can null this with my 13B2. I
> also can't figure out what this is, or if the two are
> Anyone else been through something like this, and any
> help or ideas?
> 73s John NE0P
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