Topband: [RFI] Powerline noise question

Sat Dec 31 16:54:48 EST 2022

 So I like flag antennas, the full size kind that work very good for DX reception under the right conditions. Noise hunting is an entirely different animal usually requiring an entire toolbox of equipment unless you get lucky (which never has happened for me!).

The first part of the hunt is to get an initial vector (direction) to begin looking. Assuming one has a 160 transmitting antenna on the property, most likely your 160 DF antenna what ever it is will point to your transmitting antenna as the noise source unless you have isolated it while receiving. In my instances, I had ungrounded vertical antennas and isolating them was accomplished by floating the antenna from the matching network and ground. I found just a few PF to ground would make the verticals sing loudly with noise so even one foot of coax would make it re-radiate noise!

Assuming you get the tx antenna isolated, you can begin to locate the noise..... maybe. If you have overhead powerlines to and around your property, the powerlines act as open-wire feedlines carrying the noise to your property thus negating an accurate vector to the noise source. Interesting to note that it appears that most powerline noise propagating down the power lines create a situation where the noise peaks every half wavelength of the frequency your listening to. So for 160, you get noise peaks and nulls every 500 or so feet ; so if you drive/listen in a car, the strength keeps going up and down making it difficult if not impossible to find the loudest peak because at 1.8 mhz, the signal does not attenuate very well! 

Because the noise attenuates more at higher frequencies, I usually try to the map noise on every band I have a directive antenna. If your lucky, a tribander or 2m beam will get you a vector you can better rely on. So how does the mini-flag play in this? By design the flag provides directivity over a broad range of frequencies even though the peaks and nulls of a flag are not that pronounced. So assuming you have a good portable multi-band receiver, you can search a broad range of frequencies with directivity where the higher frequencies should be weaker but more accurate in finding an initial direction.

So now you have an initial vector to begin the search. Keep in mind the higher the frequency you hear the noise the more accurate the direction should be. Assuming you drive, you will hear the 1/2 wave rise and fall of noise strength on what ever frequency you are listening to but again, the higher the frequency the better. 

I'm fortunate to have an old IC-202 2 meter portable SSB/CW transceiver that has a whip antenna. It usually can get me to the source power pole and because the whip has a very sharp null as you point it to a source, I can sometimes tell what side of the power pole has the problem!

I don't use a flag for noise location but I can see how it with a sensitive wide frequency portable RX would be a killer combo. Putting a whip antenna on the receiver as you get close and listening on VHF would be ideal for helping to find the exact pole or point causing the problem. 

W7MY
Richland, WA.

     On Saturday, December 31, 2022, 09:01:37 AM PST, <topband-request at contesting.com> wrote:  

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Today's Topics:

  1. Re: Verticals on the beach (Dino Darling)
  2. Re: [RFI] Powerline noise question (Richard (Rick) Karlquist)
  3. Re: Verticals on the beach (Dan Maguire)
  4. Re: [RFI] Powerline noise question (Frank W3LPL)
  5. Re: Verticals on the beach (n4is at comcast.net)
  6. Re: [RFI] Powerline noise question (John Kaufmann)
  7. Re: [RFI] Powerline noise question (Richard (Rick) Karlquist)

----------------------------------------------------------------------

Message: 1
Date: Fri, 30 Dec 2022 18:59:30 +0000
From: Dino Darling <dino at kx6d.com>
To: Dan Maguire <djm2150 at yahoo.com>, "topband at contesting.com"
    <topband at contesting.com>
Subject: Re: Topband: Verticals on the beach
Message-ID:
    <BYAPR08MB5638DCD5833953F0BD7E1F61F8F09 at BYAPR08MB5638.namprd08.prod.outlook.com>

Content-Type: text/plain; charset="us-ascii"

N6BT has reported that modeling software doesn't get verticals right. He concluded this after using a drone to test antennas in the real world. Modeling software does a great job on horizontal antennas, but verticals, not so much.

Dino - KX6D

-----Original Message-----
Stan, I have it on good authority that you have a modeling wizard in your back pocket.  :-)  So for anyone who might be interested in modeling a "Vertical on the Beach" scenario, in addition to Grant's QST article this AutoEZ page might be of interest:

https://ac6la.com/aepatterns.html#Part4

Dan, AC6LA
_________________
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

------------------------------

Message: 2
Date: Fri, 30 Dec 2022 12:25:47 -0800
From: "Richard (Rick) Karlquist" <richard at karlquist.com>
To: Frank W3LPL <donovanf at starpower.net>, rfi <rfi at contesting.com>,
    PVRC <pvrc at mailman.qth.net>, topband <topband at contesting.com>
Subject: Re: Topband: [RFI] Powerline noise question
Message-ID: <9413f578-cd2c-d07f-1288-43a39d3d1c5e at karlquist.com>
Content-Type: text/plain; charset=UTF-8; format=flowed

Thanks Frank.  You got me unstuck.
I have ordered the DX Engineering Kits and the PL330 receiver.

73
Rick N6RK

On 12/29/2022 7:53 PM, Frank W3LPL wrote:
> Hi Rick,
> 
> I recently built a WB8DSB man portable flag antenna (March 2021 QST)
> for RFI geolocation, its performance far exceeds my expectations.
> Its narrow deep null quickly, easily and definitively located the
> source of very troublesome 160 meter RFI to a single power pole
> more than three miles from my QTH.  Prior to constructing the
> flag antenna I could locate the RFI to only within a few hundred
> yards of the RFI source.
> 
> I built my flag antenna entirely out of materials I had on hand
> from previous projects including 3/8 inch diameter fiberglass rods,
> a pair of Advanced Receiver Research P1-30/20VD 20 dB HF preamps,
> a case of eight AA batteries to provide power to the preamps,
> a switchable attenuator and a Tecsun PL330 portable HF receiver.
> 
> I highly recommend this easily constructed RFI geolocation antenna
> for the toolkit of any serious HF operator.
> 
> 73
> Frank
> W3LPL
> 
> 
> 
> 
> 
> ----- Original Message -----
> From: "Richard" <richard at karlquist.com>
> To: "rfi" <rfi at contesting.com>
> Sent: Friday, December 30, 2022 3:15:32 AM
> Subject: [RFI] Powerline noise question
> 
> I have a powerline noise coming from about 2 miles away, which is
> nevertheless quite strong at my QTH.
> 
> Here are the symptoms:
> 
> 1.  A 120 Hz noise burst at regular intervals, about 0.9 seconds apart.
> 
> 2.  The noise goes away after a rain; then comes back after things dry
> out.
> 
> 3.  Can be heard from 500 kHz up to a few MHz.
> 
> 4.  The noise is very strong along a road for a few miles.  There is a
> 
> power line that follows the road.  I haven't been able to localize it
> better than
> 
> that so far.  From my QTH, though, it is definitely coming in at a
> specific azimuth
> 
> which is consistent with the noisy road a few miles away.  (Using a loop
> antenna
> 
> for DF'ing).
> 
> Any help appreciated.
> 

------------------------------

Message: 3
Date: Fri, 30 Dec 2022 22:06:32 +0000 (UTC)
From: Dan Maguire <djm2150 at yahoo.com>
To: Stan Stockton <wa5rtg at gmail.com>
Cc: topband at contesting.com
Subject: Re: Topband: Verticals on the beach
Message-ID: <527958368.2065022.1672437992846 at mail.yahoo.com>
Content-Type: text/plain; charset=UTF-8

 Stan Stockton wrote:
>>> Specifically what I want to find out is how much louder I would likely be in Europe from 25 degrees to 50 degrees if the vertical was on that line you drew as compared to being 70 feet below the line.

>>> Can AutoEZ be used to model this?

Yes, but only assuming that the water's edge is a straight line parallel to the Y axis. Here's a comparison of the azimuth patterns at a 10? elevation angle when a) the vertical is right at the water's edge and b) the vertical is 70 feet back from the water. Land is to the left of the Y axis and water is to the right.

https://i.postimg.cc/j5RDRMGz/image.png

The green dot marker is at 5? "into the water" since the water's edge is along the up/down Y axis. At that azimuth there is a 5.3 dB advantage to having the vertical at the water's edge. In contrast, looking straight out over the water (along the X axis) the advantage of being at the edge is only 0.8 dB.

In the image above, a second set of azimuth ring labels (in parenthesis) has been added. This "compass rose" set of labels will help to mentally rotate the entire chart such that the water's edge (the Y axis) aligns with your physical location. Here's another image explaining that second set of labels.

https://i.postimg.cc/zfrBkdD9/image.png

Dan, AC6LA  

------------------------------

Message: 4
Date: Fri, 30 Dec 2022 20:08:01 -0500 (EST)
From: Frank W3LPL <donovanf at starpower.net>
To: Richard <richard at karlquist.com>
Cc: rfi <rfi at contesting.com>, PVRC <pvrc at mailman.qth.net>,     topband
    <topband at contesting.com>
Subject: Re: Topband: [RFI] Powerline noise question
Message-ID:
    <188535693.10977839.1672448881671.JavaMail.zimbra at starpower.net>
Content-Type: text/plain; charset=utf-8

Rick,

You'll be very pleased with the performance of the WB8DSB RFI hunting
flag antenna.  

Don't forget to need lots of preamp gain. The WB8DSB flag is about 60 dB
down from a dipole on 160 meters. 40 dB of preamp gain is needed until
you're very close to the RFI source.

73
Frank
W3LPL

----- Original Message -----
From: "Richard" <richard at karlquist.com>
To: "Frank W3LPL" <donovanf at starpower.net>, "rfi" <rfi at contesting.com>, "PVRC" <pvrc at mailman.qth.net>, "topband" <topband at contesting.com>
Sent: Friday, December 30, 2022 8:25:47 PM
Subject: Re: [RFI] Powerline noise question

Thanks Frank.  You got me unstuck.
I have ordered the DX Engineering Kits and the PL330 receiver.

73
Rick N6RK

On 12/29/2022 7:53 PM, Frank W3LPL wrote:
> Hi Rick,
> 
> I recently built a WB8DSB man portable flag antenna (March 2021 QST)
> for RFI geolocation, its performance far exceeds my expectations.
> Its narrow deep null quickly, easily and definitively located the
> source of very troublesome 160 meter RFI to a single power pole
> more than three miles from my QTH.  Prior to constructing the
> flag antenna I could locate the RFI to only within a few hundred
> yards of the RFI source.
> 
> I built my flag antenna entirely out of materials I had on hand
> from previous projects including 3/8 inch diameter fiberglass rods,
> a pair of Advanced Receiver Research P1-30/20VD 20 dB HF preamps,
> a case of eight AA batteries to provide power to the preamps,
> a switchable attenuator and a Tecsun PL330 portable HF receiver.
> 
> I highly recommend this easily constructed RFI geolocation antenna
> for the toolkit of any serious HF operator.
> 
> 73
> Frank
> W3LPL
> 
> 
> 
> 
> 
> ----- Original Message -----
> From: "Richard" <richard at karlquist.com>
> To: "rfi" <rfi at contesting.com>
> Sent: Friday, December 30, 2022 3:15:32 AM
> Subject: [RFI] Powerline noise question
> 
> I have a powerline noise coming from about 2 miles away, which is
> nevertheless quite strong at my QTH.
> 
> Here are the symptoms:
> 
> 1.  A 120 Hz noise burst at regular intervals, about 0.9 seconds apart.
> 
> 2.  The noise goes away after a rain; then comes back after things dry
> out.
> 
> 3.  Can be heard from 500 kHz up to a few MHz.
> 
> 4.  The noise is very strong along a road for a few miles.  There is a
> 
> power line that follows the road.  I haven't been able to localize it
> better than
> 
> that so far.  From my QTH, though, it is definitely coming in at a
> specific azimuth
> 
> which is consistent with the noisy road a few miles away.  (Using a loop
> antenna
> 
> for DF'ing).
> 
> Any help appreciated.
>

------------------------------

Message: 5
Date: Fri, 30 Dec 2022 20:50:55 -0500
From: <n4is at comcast.net>
To: "'Stan Stockton'" <wa5rtg at gmail.com>
Cc: <topband at contesting.com>
Subject: Re: Topband: Verticals on the beach
Message-ID: <004501d91cba$56392260$02ab6720$@comcast.net>
Content-Type: text/plain;    charset="UTF-8"

Well

People believe on what they want to believe. The difference from close to the water and far from the water is zero, nada, don?t bother.  10 FT , 100 FT and 1000 FT is the same. The difference "in" the water is > + 10 db., This is based on real experience and not a simulation on computer, please search  the list archives for vertical on the water. You will find priceless information about it.

http://lists.contesting.com/archives/html/Topband/

A practical issue is the change in impedance that can be solved with a remote antenna tuner.

73's
JC
N4IS

------------------------------

Message: 6
Date: Sat, 31 Dec 2022 02:34:16 +0000 (UTC)
From: John Kaufmann <john.kaufmann at verizon.net>
To: "topband at contesting.com" <topband at contesting.com>
Subject: Re: Topband: [RFI] Powerline noise question
Message-ID: <1917309465.5630994.1672454056816 at mail.yahoo.com>
Content-Type: text/plain; charset=UTF-8

The WD8DSB mini-flag truly is a fantastic RFI-hunting tool.? When I saw the original article in QST, I recognized immediately that this was a great "invention" by WD8DSB.? Like many of you, I deal with quite a bit of man-made RFI on 160m, so I bought one of the very first ones sold by DX Engineering.? Of course, it's not hard to build your own from the QST article.? The antenna?is very broadband and works from?the medium wave bands up to at least 50 MHz.? Having a unidirectional pattern with a sharp null off the back is a huge advantage over conventional bidirectional DF loops.? You can narrow down direction of signal arrival unambiguously to within a few degrees.
As?W3LPL says, it is a very low gain antenna that?does need a very good preamp behind it.? You need?a preamp with not only a lot of gain but also a very good noise figure because ultimately the sensitivity for hunting weak signals is limited by noise.? I have the companion preamp that DX Engineering sells for this antenna.? Its noise figure is about 4 to 5 dB, which is quite good for a reasonably priced, battery-powered preamp that you can carry around with you.? By way of comparison, I also have a homebrew high gain (35 dB) preamp, made with MMIC's, with a noise figure of 2 dB, which is very close to the best you can do for HF.? However, most of the time I use the DX Engineering preamp because it is good enough for all but the weakest signals.
Bottom line is that the WD8DSB mini-flag and a portable receiver are all you need for tracking down noise sources.? As one more auxiliary tool, I sometimes use the tinySA Ultra (an improved version of the original tinySA hand-portable spectrum analyzer) to look at the spectral signature of a suspected source in the field to confirm it's the same source that I'm seeing at my station.? See tinysa.org/wiki/ for more information.
Disclaimers:? I have no affiliation or commercial interest in DX Engineering or the tinySA product.
73, John W1FV

-----Original Message-----
From: Frank W3LPL <donovanf at starpower.net>
To: Richard <richard at karlquist.com>
Cc: rfi <rfi at contesting.com>; PVRC <pvrc at mailman.qth.net>; topband <topband at contesting.com>
Sent: Fri, Dec 30, 2022 8:09 pm
Subject: Re: Topband: [RFI] Powerline noise question

Rick,

You'll be very pleased with the performance of the WB8DSB RFI hunting
flag antenna.? 

Don't forget to need lots of preamp gain. The WB8DSB flag is about 60 dB
down from a dipole on 160 meters. 40 dB of preamp gain is needed until
you're very close to the RFI source.

73
Frank
W3LPL

----- Original Message -----
From: "Richard" <richard at karlquist.com>
To: "Frank W3LPL" <donovanf at starpower.net>, "rfi" <rfi at contesting.com>, "PVRC" <pvrc at mailman.qth.net>, "topband" <topband at contesting.com>
Sent: Friday, December 30, 2022 8:25:47 PM
Subject: Re: [RFI] Powerline noise question

Thanks Frank.? You got me unstuck.
I have ordered the DX Engineering Kits and the PL330 receiver.

73
Rick N6RK

------------------------------

Message: 7
Date: Fri, 30 Dec 2022 20:36:31 -0800
From: "Richard (Rick) Karlquist" <richard at karlquist.com>
To: Frank W3LPL <donovanf at starpower.net>
Cc: rfi <rfi at contesting.com>, PVRC <pvrc at mailman.qth.net>,    topband
    <topband at contesting.com>
Subject: Re: Topband: [RFI] Powerline noise question
Message-ID: <0b0770e2-5e10-a9ab-e5de-89d8b7e3baa3 at karlquist.com>
Content-Type: text/plain; charset=UTF-8; format=flowed

I am going to start with the preamp kit DXE sells to go with the flag 
kit.  This particular noise source is extremely strong so I am 
optimistic that it will be sufficient.  I can add the preamp that
came with my Pixel loop if necessary.

Again, your recommendation means a lot.

73
Rick N6RK

On 12/30/2022 5:08 PM, Frank W3LPL wrote:
> Rick,
> 
> You'll be very pleased with the performance of the WB8DSB RFI hunting
> flag antenna.
> 
> Don't forget to need lots of preamp gain. The WB8DSB flag is about 60 dB
> down from a dipole on 160 meters. 40 dB of preamp gain is needed until
> you're very close to the RFI source.
> 
> 73
> Frank
> W3LPL
> 
> ----- Original Message -----
> From: "Richard" <richard at karlquist.com>
> To: "Frank W3LPL" <donovanf at starpower.net>, "rfi" <rfi at contesting.com>, "PVRC" <pvrc at mailman.qth.net>, "topband" <topband at contesting.com>
> Sent: Friday, December 30, 2022 8:25:47 PM
> Subject: Re: [RFI] Powerline noise question
> 
> Thanks Frank.  You got me unstuck.
> I have ordered the DX Engineering Kits and the PL330 receiver.
> 
> 73
> Rick N6RK
> 
> On 12/29/2022 7:53 PM, Frank W3LPL wrote:
>> Hi Rick,
>>
>> I recently built a WB8DSB man portable flag antenna (March 2021 QST)
>> for RFI geolocation, its performance far exceeds my expectations.
>> Its narrow deep null quickly, easily and definitively located the
>> source of very troublesome 160 meter RFI to a single power pole
>> more than three miles from my QTH.  Prior to constructing the
>> flag antenna I could locate the RFI to only within a few hundred
>> yards of the RFI source.
>>
>> I built my flag antenna entirely out of materials I had on hand
>> from previous projects including 3/8 inch diameter fiberglass rods,
>> a pair of Advanced Receiver Research P1-30/20VD 20 dB HF preamps,
>> a case of eight AA batteries to provide power to the preamps,
>> a switchable attenuator and a Tecsun PL330 portable HF receiver.
>>
>> I highly recommend this easily constructed RFI geolocation antenna
>> for the toolkit of any serious HF operator.
>>
>> 73
>> Frank
>> W3LPL
>>
>>
>>
>>
>>
>> ----- Original Message -----
>> From: "Richard" <richard at karlquist.com>
>> To: "rfi" <rfi at contesting.com>
>> Sent: Friday, December 30, 2022 3:15:32 AM
>> Subject: [RFI] Powerline noise question
>>
>> I have a powerline noise coming from about 2 miles away, which is
>> nevertheless quite strong at my QTH.
>>
>> Here are the symptoms:
>>
>> 1.  A 120 Hz noise burst at regular intervals, about 0.9 seconds apart.
>>
>> 2.  The noise goes away after a rain; then comes back after things dry
>> out.
>>
>> 3.  Can be heard from 500 kHz up to a few MHz.
>>
>> 4.  The noise is very strong along a road for a few miles.  There is a
>>
>> power line that follows the road.  I haven't been able to localize it
>> better than
>>
>> that so far.  From my QTH, though, it is definitely coming in at a
>> specific azimuth
>>
>> which is consistent with the noisy road a few miles away.  (Using a loop
>> antenna
>>
>> for DF'ing).
>>
>> Any help appreciated.
>>
> 

------------------------------

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