Re: Topband: [RFI] Powerline noise question
Karlquist) -- Message: 1 Date: Fri, 30 Dec 2022 18:59:30 + From: Dino Darling To: Dan Maguire , "topband@contesting.com" Subject: Re: Topband: Verticals on the beach Message-ID: 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" To: Frank W3LPL , rfi , PVRC , topband Subject: Re: Topband: [RFI] Powerline noise question Message-ID: <9413f578-cd2c-d07f-1288-43a39d3d1...@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" To: "rfi" 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 + (UTC) From: Dan Maguire To: Stan Stockton Cc: topband@contesting.com Subject: Re: Topband: Verticals on the beach Message-ID: <527958368.2065022.1672437992...@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 To: Richa
Re: Topband: [RFI] Powerline noise question
la.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" To: Frank W3LPL , rfi , PVRC , topband Subject: Re: Topband: [RFI] Powerline noise question Message-ID: <9413f578-cd2c-d07f-1288-43a39d3d1...@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" > To: "rfi" > 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 + (UTC) From: Dan Maguire To: Stan Stockton Cc: topband@contesting.com Subject: Re: Topband: Verticals on the beach Message-ID: <527958368.2065022.1672437992...@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 To: Richard Cc: rfi , PVRC , topband Subject: Re: Topband: [RFI] Powerline noise question Message-ID: <188535693.10977839.1672448881671.javamail.zim...@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 - Fr
Re: Topband: [RFI] Powerline noise question
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" To: "Frank W3LPL" , "rfi" , "PVRC" , "topband" 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" To: "rfi" 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. _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: [RFI] Powerline noise question
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 To: Richard Cc: rfi ; PVRC ; topband 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" To: "Frank W3LPL" , "rfi" , "PVRC" , "topband" 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 _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
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" To: "Frank W3LPL" , "rfi" , "PVRC" , "topband" 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" > To: "rfi" > 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. > _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: [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" To: "rfi" 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. _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: [RFI] Powerline noise question
Hi Jim, Below is a link to a simple website I have for my portable flag antenna and you will find a link in the first paragraph of my website to the original QST article (with the permission of the ARRL). DX Engineering also sells what they call their NoiseLoop which is based on my portable flag and they also sell a preamplifier specifically designed for use with my portable flag that works really well. https://sites.google.com/site/portableflagantenna/home P.S. I make no money on anything that DX Engineering sells, including my portable flag. 73, Don (wd8dsb) On Fri, Dec 30, 2022 at 2:13 AM Jan Erik Holm via Topband < topband@contesting.com> wrote: > Can a description of that antenna be had ? > Google was not my friend and I don´t have QST. > > / Jim SM2EKM > > Den 2022-12-30 kl. 04:53, skrev Frank W3LPL: > > 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 > > > _ > Searchable Archives: http://www.contesting.com/_topband - Topband > Reflector > _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: [RFI] Powerline noise question
Can a description of that antenna be had ? Google was not my friend and I don´t have QST. / Jim SM2EKM Den 2022-12-30 kl. 04:53, skrev Frank W3LPL: 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 _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: [RFI] Powerline noise question
Frank. . . about a year or so ago I had a nasty RFI problem on TB present when I was looking toward Europe. It only appeared from November through March (prime TB season) and was about S7 on the transmit array. I had struggled trying to get it isolated. My local power company was very cooperative and willing to help (which they did) but did not have much technical capability needed to isolate the problem. After living with it for a whole season I ordered the WD8DSB portable flag kit from DX Engineering after seeing the QST article below and talking with Don/WD8DSB. Upon Don's advice I also picked up a Radio Shack DX-440 portable receiver off of EBay. The flag and DX-440 make a dynamite combination (the receiver is remarkably good for something that was not too expensive to begin with). After searching for the interference source for over a year, within a couple days of completing construction of the loop I had my problem isolated to a Chinese manufactured float charger on a motorcycle battery about 0.75 miles away (motorcycle being stored during off season). The charger was transmitting the interference back through the service panel, the transformer and out onto the single phase distribution line which was radiating like crazy. I can highly recommend the WD8DXB flag kit from DX Engineering or build one yourself. Put a good sensitive receiver with it like the Realistic DX-440 and you'll have a very effective portable (on foot) way of DFing interference. 73 and Happy New Year to all. . . Dave, W0FLS On 12/29/2022 9:53 PM, Frank W3LPL wrote: I recently built a WB8DSB man portable flag antenna (March 2021 QST) _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: [RFI] Powerline noise question
Rick, When I mentioned using an AM radio with a 3 or 4 element yagi when within 0.25 miles of the source I should have said that’s up on VHF (like 136 or 146 MHz, etc.) if it’s really power line noise (arcing hardware). Don wd8dsb On Thu, Dec 29, 2022 at 11:27 PM Don Kirk wrote: > Hi Frank, > > Thanks for mentioning my portable flag, and that's the way to go to get > close to the area of the suspect pole but I didn't want to toot my own > horn. It really is an easy antenna to build and its build is very > forgiving, and glad to hear it exceeded your expectations. > > I do recommend using my portable flag out in the clear in order to avoid a > distorted pattern such as developing a minor lobe off the backside if > standing too close to an existing object like a tall metal light pole or a > house, etc. When in doubt I use the peak of my portable flag as it's much > more robust (less prone to getting altered by nearby objects). The > unidirectional properties of the portable flag is priceless as well as its > broadband response. I use a 680 ohm termination resistor but a 820 ohm > termination resistor works well too. > > 73, > Don (wd8dsb) > > On Thu, Dec 29, 2022 at 10:54 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" > > To: "rfi" > > 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. > > > > -- > > Rick Karlquist > > N6RK > > ___ > > RFI mailing list > > r...@contesting.com > > http://lists.contesting.com/mailman/listinfo/rfi > > _ > > Searchable Archives: http://www.contesting.com/_topband - Topband > > Reflector > > > ___ > RFI mailing list > r...@contesting.com > http://lists.contesting.com/mailman/listinfo/rfi > _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: [RFI] Powerline noise question
Hi Frank, Thanks for mentioning my portable flag, and that's the way to go to get close to the area of the suspect pole but I didn't want to toot my own horn. It really is an easy antenna to build and its build is very forgiving, and glad to hear it exceeded your expectations. I do recommend using my portable flag out in the clear in order to avoid a distorted pattern such as developing a minor lobe off the backside if standing too close to an existing object like a tall metal light pole or a house, etc. When in doubt I use the peak of my portable flag as it's much more robust (less prone to getting altered by nearby objects). The unidirectional properties of the portable flag is priceless as well as its broadband response. I use a 680 ohm termination resistor but a 820 ohm termination resistor works well too. 73, Don (wd8dsb) On Thu, Dec 29, 2022 at 10:54 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" > To: "rfi" > 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. > > -- > Rick Karlquist > N6RK > ___ > RFI mailing list > r...@contesting.com > http://lists.contesting.com/mailman/listinfo/rfi > _ > Searchable Archives: http://www.contesting.com/_topband - Topband > Reflector > _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: [RFI] Powerline noise question
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" To: "rfi" 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. -- Rick Karlquist N6RK ___ RFI mailing list r...@contesting.com http://lists.contesting.com/mailman/listinfo/rfi _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
