Hi Doug will give you my experience with noise (power line) and the JPS
ANC-4. First the power line noise. I had severe noise during the Heard Is.
Dxpedition and was in a wild state of frustration the time they were on. I
began searching for the noise from within the home qth and surrounding
neighbors by using the methods already mentioned, i.e.: turning off breakers,
appliances, portable am radio walking around the neighborhood, etc. I
eventually narrowed it down to power line noise and contacted the power co.
They are a big outfit here in VA and since this was during a time of severe
winter weather the power co. had other problems on their mind other than my
power line noise. They weren't to responsive to my requests and after approx.
2-3 more phone calls within about 4-5 days I eventually asked to speak to one
of the head "honchos". He sympathized with my problem but explained he only
had one crew responsible for such complaints,and they were already "strapped"
with other problems keeping power up and running with the severe cold, ice,
etc. I then advised him that I had done some research and that from what I
had read they (the power co.) had a responsibility to run a clean system
according to FCC regs. He agreed with me and all of a sudden seemed willing
to look into the problem ASAP but that he would like my help. I told him I
had already narrowed it down to pole locations and #'s and I would be more
than willing to share this info. with his techs. and also make myself
available to help "fox hunt" any problems if he wanted to set up a
pre-arranged time. He agreed to get on the problem and I had already
collected some of the needed info. for his crew by first swinging the beam in
different directions and getting bearings on where the severe noise may be
coming from. I then rode up and down the street with my truck radio tuned to
the am broadcast band where there was no signal present and listened for the
line noise. This was a general search method and I further narrowed it down
by simultaneously having a scanner or 2m rig which can tune the am vhf
aircraft band with a 5-6 step switchable attenuator in line similar to that
used for "fox hunting", antenna testing, etc. The attenuator with vhf radio
did the trick. As I went by each pole, transformer, etc. I would throw in
some db of attenuation up to 20-40 db until the noise was barely present and
narrowed it down right to the poles in question that my truck was sitting next
to. Bottom line: my data matched his crews data and the problem was corrected
within 2 weeks after the "FCC" referenced phone call and after the main man
got the msg. I wasn't just gonna sit at home and wait for them to respond when
the weather got nice, warm, and sunny! BTW worked Heard on 20m from my qth,
but had to run over to buddies house to get them on 40m due to the line noise!
Now for the JPS, I picked one up right after the problem was finally solved
and It does seem to work very well in conjunction with my noise blanker on the
TS-940. However I don't think with the severe line noise problem I had at the
time it would help have helped very much, (we'll never know now) due to the
fact my noise level here at the time was s-9+40-60db! It wiped out all HF
com. and the only reason I got Heard on 20m from my QTH was cause it warmed up
to around 40-50 deg. that day. You see the line noise problem was all
related to the extreme cold and moisture in the air during the time period
involved as pole components were suffering freezing and thawing, wet and dry,
etc. The problem of the line noise was caused by a bad batch of "arrestors"
they had installed about 10-15 years ago and they were going to have
systematically start replacing them as they failed and did regular
maintenance. So there you have it, kinda lengthy but hope it is informative
for you and others out there who may experience line noise and some ways to
tackle it 73! Ed=K5OF.
Doug Brandon wrote:
> I've been plauged with some pretty bad local noise for quite a while now.
> It sounds like power line or some other sort of mechanically generated
> noise that shows up out of the blue and stays on at a constant high level
> for many days at a time. It doesnt just go away, but sort of "bleeds" off
> and slowly diminishes in strength over a few days until it completely
> disappears. Sometimes it is quiet for weeks, and other times it doesnt
> go away for weeks. The noise blanker in my 930S manages to chop it down
> from S8-S9 down to the S3-S4 level, but obviously strong adjacent signals
> cause the front end to chop like crazy. I've tried to keep a log of when
> it occurs to see if there is any sort of pattern, but I gave up since it
> seems to be pretty random.
>
> The noise doesnt peak in any direction when I turn my beam. I've also
> walked around the neighborhood with a transistor radio and was unable to
> find anything. The noise is strong on HF, VHF, UHF, and even causes
> sparkles on my cable TV. I have another ham friend who lives about a
> mile away and he doesnt experience this, so I know it's something in
> or near my neighborhood.
>
> Anyway, the bottom line is that I'm wondering if anybody has used the
> JPS ANC-4 or corresponding MFJ product with success. I've heard they
> do a pretty good job with man-made noise which is what I seem to be
> dealing with. I doubt I'll ever get rid of this noise, so I'm hoping
> one of these devices will help my situation.
>
> 73 de Doug, N6RT
>
> /*-------------------------------------------------------------------*/
> Doug Brandon http://www.kaiwan.com/~dab dab@kaiwan.com
>
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