Forgot to add -- I especially like the tolerance value given by W1HIS in his
loop diagram as +/- 0.0001 inch. Good one!
Paul, W9AC
----- Original Message -----
From: "chuck shinn" <chuck.shinn@verizon.net>
To: <rfi@contesting.com>
Sent: Saturday, October 09, 2010 2:56 PM
Subject: Re: [RFI] Power Line Noise Conundrum
> I have been successful in remedying my local noise with the help of a
> small, easily built, B Field Loop and a cheap short wave receiver with
> an external antenna jack. With this setup I can locate a direction, a
> wire or a pole very easily. You can see what I am talking about here:
> http://w5pg.wordpress.com/2009/10/17/noise/ or closer up view at:
> http://w5pg.wordpress.com/2010/04/22/serendipity-marconi-day-and-some-noise-help/sniffing_loop_dwg-3/
> Simply listen in AM mode and wand your home/area at the frequency that
> is of interest and rotate the wand to null and insure you are at the
> correct wire/conduit/pole etc.
> Chuck W1HIS shared this with me and has been a very large help over the
> years. My short wave receiver is a simple Yachtboy I picked up at Fry's
> as an open box special for about 25 dollars. Recently this helped me
> locate noise on AC Air handler plumbing and Natty Gas pipe that were
> killing me on 30M. It is essentially a free construction project and
> works wonderfully, far better than any yagi or quagi I have tried at
> higher frequencies. Best, Chas
>
>
> On 10/9/2010 1:39 PM, Kim Elmore wrote:
>> I have a recurring power line RFI issue. At one point, it seemed to
>> have been remedied, but has returned. It sounds similar to what I had
>> earlier in the spring. That was repaired by the power company along
>> with the help of a tornado (really!).
>>
>> Now, though, I hear it again.
>>
>> Trying to be helpful, I'm trying to track it down and have had
>> confusing results. First, I've tried chasing it with my rotatable
>> antennas as home. I have K9AY loops that have a good null off the
>> back. I laso have a 2 el 40 beam, along with a 20 m-10 m tribander
>> and a dipole for 30 m-12 m. Depending on the time of day, I hear it
>> pretty much everywhere relatively well, save for 20 m, which seems to
>> be the quietest.
>>
>> On 80 m with the K9AY loops, I have minimum noise when the null is
>> either SW or NE; which strikes me as inconsistent.
>>
>> On the 2 el 40 m bean, I get deep, narrow nulls off of what i believe
>> to be the sides when it is oriented either N or S. I also get a
>> weaker null when it's pointed roughly W, indicating the source is to my
>> East.
>>
>> I don't hear much noise on 20 m. On 15 m I get a null to the N, but
>> on 10 m I get a null to the S! the antennas work as they should (CW
>> signals are peaked when the antenna is pointed at their source).
>>
>> Using the dipole, I get weak nulls when it's pointed N or S.
>>
>> I have a corner reflector for 2 m and 70 cm but cannot hear anything
>> on either band when I use AM detection regardless of where it's pointed.
>>
>> I drove around the area in my car, using my dual-band rig set for AM
>> detection. Using 2 m, I tended to hear it over a broad stretch along
>> a road that is about 1/2 mi to my east. I found a localized source to
>> my ENE when I went up to 70 cm. I suspect that is the source, as it's
>> very near a pole that carries quite a bit of hardware (lots off bell
>> insulators and lighting arrestors) and what appears to be a 25 kV line.
>>
>> But I'm perplexed about the inconsistency I hear using my HF
>> antennas. Is this because of standing waves along the lines, or am I
>> hearing different sources? And, how can I use this to be most helpful
>> to the power company? They were very helpful the last time and I
>> don't want to send them on any wild goose chases.
>>
>> 73,
>>
>> Kim Elmore N5OP
>>
>> _______________________________________________
>> RFI mailing list
>> RFI@contesting.com
>> http://lists.contesting.com/mailman/listinfo/rfi
>>
>
> --
> _______________________________________________
> RFI mailing list
> RFI@contesting.com
> http://lists.contesting.com/mailman/listinfo/rfi
_______________________________________________
RFI mailing list
RFI@contesting.com
http://lists.contesting.com/mailman/listinfo/rfi
|