Re: Topband: Another take on power line noise hunting
I use an old IC-202 (2m battery powered ssb/cw transceiver). It has a whip antenna and provides a very directive null off of the tip of the whip. - Greg Chartrand - W7MY Richland, WA. DN-06IF W7MY Home Page: http://webpages.charter.net/w7my/ _ Topband Reflector
Re: Topband: Another take on power line noise hunting
Re a portable oscilloscope to look at noise signatures (the number of "points" on the waveform is a basic but good way and u can usually discern multiple sources too) is to use a audio spectrum analyZer ap on an iPhone. I assume these may be available on a Droid too. I use several and some are free or close to free. You can actually use the microphone on the fone as the pickup if you can couple to the receiver with a piece of cloth. These aps are fairly decent too being able to change time base and amplitude. Of course a small laptop with a PC based application is better and you can plug into the line input and get a more reliable reading and record the noise as well. 73 Pete W2PM Sent from my iPhone On Jan 6, 2013, at 6:40 AM, Pete Smith N4ZR wrote: > Or, since you don't really need a calibrated result, build a simple variable > attenuator. Just about anything works so long as you can vary the > sensitivity as you approach the power line. > > 73, Pete N4ZR > Check out the Reverse Beacon Network at > http://reversebeacon.net, > blog at reversebeacon.blogspot.com. > For spots, please go to your favorite > ARC V6 or VE7CC DX cluster node. > > On 1/5/2013 1:17 PM, donov...@starpower.net wrote: >> Hi Paul, >> >> You would helpful a step attenuator, in 1 dB steps, to be a valuable >> addition to your tool bag. There are situations where it helps isolate to >> an individual pole. Its much more accurate than an S-meter. >> >> Something like this, or many other alternatives: >> >> http://www.ebay.com/itm/Coaxial-RF-Step-Attenuator-Set-1-dB-steps-to-70-dB-total-DC-to-1-GHz-/200866468929?pt=LH_DefaultDomain_0&hash=item2ec4931441 >> >> 73 >> Frank >> W3LPL >> >> ---- Original message >>> Date: Sat, 05 Jan 2013 11:44:08 -0500 >>> From: N1BUG >>> Subject: Topband: Another take on power line noise hunting >>> To: Topband >>> >>> I've been following this discussion with interest. I spent the >>> summer tracking down more than 20 sources of power line noise. As an >>> offshoot of that I've made it my mission to help clean up RFI in my >>> little corner of the world. I've been slowly drifting away from >>> DXing and this has turned out to be my new area of interest. >>> >>> Since this topic is perhaps of interest to topbanders, and since my >>> experiences seem to vary somewhat from the typical reported here so >>> far, I thought I would take a moment to share some observations. I >>> should probably note I was dealing with a mix of 13.2 kV >>> distribution lines and 46 kV transmission lines. My hunt was made >>> more challenging by the fact I had multiple sources in a relatively >>> small area and could often hear more than one at a time even with >>> directional antennas and attenuation. >>> >>> My tools this summer were 135 MHz AM receiver with 3 element yagi >>> and step attenuator; LF/MF/HF/VHF/UHF AM receiver with DF loops for >>> low bands and 7 element yagi for 445 MHz; ultrasonic receiver with dish. >>> >>> Low frequencies, eg. AM BC or 160 meters were *occasionally* useful >>> in locating a general source area. Sometimes the area identified >>> turned out to be an area of *radiation* but the noise was >>> *generated* elsewhere. Often the relatively close proximity of >>> multiple sources made low frequency tracking useless. >>> >>> VHF was always useful in finding a source area, 80% of the time >>> resolving it to a single pole. The sharp, deep null at exactly 90 >>> degrees off axis of the yagi proved very useful for confirming a >>> source structure. Poor resolution/accuracy of signal strength >>> metering was perceived as a problem. >>> >>> UHF was very helpful in a few areas where the noise was particularly >>> strong at VHF and/or signal strength so close over a span of several >>> poles that VHF could not pick the source pole with high confidence. >>> So far, experience indicates this is more likely to happen on the >>> transmission lines. They're a bear. Again, poor or no signal >>> strength metering (signal below AGC threshold) was perceived as a >>> problem. >>> >>> The first ultrasonic unit tried was a waste, finding something at >>> only 10% of RF noisy poles. The second unit was able to hear >>> something from about 60% of the same 21 poles. The figures are >>> averages over more than 10 runs with each unit. The two were also >>> tested on a spark signal range u
Re: Topband: Another take on power line noise hunting
Or, since you don't really need a calibrated result, build a simple variable attenuator. Just about anything works so long as you can vary the sensitivity as you approach the power line. 73, Pete N4ZR Check out the Reverse Beacon Network at http://reversebeacon.net, blog at reversebeacon.blogspot.com. For spots, please go to your favorite ARC V6 or VE7CC DX cluster node. On 1/5/2013 1:17 PM, donov...@starpower.net wrote: Hi Paul, You would helpful a step attenuator, in 1 dB steps, to be a valuable addition to your tool bag. There are situations where it helps isolate to an individual pole. Its much more accurate than an S-meter. Something like this, or many other alternatives: http://www.ebay.com/itm/Coaxial-RF-Step-Attenuator-Set-1-dB-steps-to-70-dB-total-DC-to-1-GHz-/200866468929?pt=LH_DefaultDomain_0&hash=item2ec4931441 73 Frank W3LPL Original message Date: Sat, 05 Jan 2013 11:44:08 -0500 From: N1BUG Subject: Topband: Another take on power line noise hunting To: Topband I've been following this discussion with interest. I spent the summer tracking down more than 20 sources of power line noise. As an offshoot of that I've made it my mission to help clean up RFI in my little corner of the world. I've been slowly drifting away from DXing and this has turned out to be my new area of interest. Since this topic is perhaps of interest to topbanders, and since my experiences seem to vary somewhat from the typical reported here so far, I thought I would take a moment to share some observations. I should probably note I was dealing with a mix of 13.2 kV distribution lines and 46 kV transmission lines. My hunt was made more challenging by the fact I had multiple sources in a relatively small area and could often hear more than one at a time even with directional antennas and attenuation. My tools this summer were 135 MHz AM receiver with 3 element yagi and step attenuator; LF/MF/HF/VHF/UHF AM receiver with DF loops for low bands and 7 element yagi for 445 MHz; ultrasonic receiver with dish. Low frequencies, eg. AM BC or 160 meters were *occasionally* useful in locating a general source area. Sometimes the area identified turned out to be an area of *radiation* but the noise was *generated* elsewhere. Often the relatively close proximity of multiple sources made low frequency tracking useless. VHF was always useful in finding a source area, 80% of the time resolving it to a single pole. The sharp, deep null at exactly 90 degrees off axis of the yagi proved very useful for confirming a source structure. Poor resolution/accuracy of signal strength metering was perceived as a problem. UHF was very helpful in a few areas where the noise was particularly strong at VHF and/or signal strength so close over a span of several poles that VHF could not pick the source pole with high confidence. So far, experience indicates this is more likely to happen on the transmission lines. They're a bear. Again, poor or no signal strength metering (signal below AGC threshold) was perceived as a problem. The first ultrasonic unit tried was a waste, finding something at only 10% of RF noisy poles. The second unit was able to hear something from about 60% of the same 21 poles. The figures are averages over more than 10 runs with each unit. The two were also tested on a spark signal range under somewhat controlled conditions. These things are definitely not created equal! To date I have identified and had the power company fix almost everything I have worked on. The remaining open case involves a short section of a 46 kV transmission line which is extremely perplexing due to the specific nature of the issue (details on request). Just when I starting thinking I was getting good at this, I came up against this one. If I were doing this strictly for myself these tools would be more than adequate. Since I'm not and I only have so many hours in a day I have several upgrades on my wish list: HF/VHF/UHF AM receiver with wider bandwidth better signal strength metering Log periodic dipole array covering ~100 to ~900 MHz for frequency agility while maintaining some directional properties Portable oscilloscope for observing noise signatures in the field (I'm hoping it helps sort out overlapping source radiations) Yet another upgrade of the ultrasonic unit. Comments are welcome, even if it's to tell me I'm clueless! :) 73 -- Paul Kelley, N1BUG RFI Committee chair, Piscataquis Amateur Radio Club http://www.k1pq.org ___ Stew Perry Topband Distance Challenge coming on December 29th. ___ Stew Perry Topband Distance Challenge coming on December 29th. ___ Stew Perry Topband Distance Challenge coming on December 29th.
Re: Topband: Another take on power line noise hunting
Thanks for adding to the discussion Don. That reminds me I forgot a couple of important details so I'm replying on-list to add them. I hadn't thought about using a spectrum analyzer even though I'm well aware of the increasing high frequency component as you get closer to the source. The bloom sounds like an even quicker way to get very close to the source than the variable frequency method (assuming, perhaps, there aren't too many overlapping noise radiations from multiple sources). I forgot to add I have been using a UHF FM link to hear audio from my home receiver in the field. In early stages with multiple noise sources being heard at home and in the field I couldn't sort one from the others by ear. I could sort them pretty well at home where I had the scope and felt that having one in the field would have saved me countless hours of frustration. In later stages comparing by ear started to be useful, though with some of the steady noises it was difficult to know for sure if I had the right one. I also had (and still have) many sources in the field that I do not hear at home on any band. I'm leaving them alone. It's amazing that I have one not more than 500 feet several of my antennas. Loud on HF through 135 MHz as I pass by it, deafening on ultrasound, but not a whisper of it at home. I would agree most folks may not need the ultrasonic unit but I owe mine a huge debt of gratitude and will never be without one - preferably the most capable one I can get my hands on. It saved my bacon this summer. The power company had been out and wrote a work order to address multiple problems. Three months had passed and the work had supposedly been completed, yet I still had noise from all but one of those poles. Nothing I said about my RF observations was convincing him to come out and check again. He was doing everything possible to convince me I couldn't possibly have power line noise any more and whatever I was hearing must be generated in a home and radiated from power lines. I wouldn't have been the first to go down in flames dealing with this company. I was losing the argument big time until I asked him to kindly explain why I could be hearing ultrasound from a particular insulator and the changing sound pattern matched up perfectly with audio from the home receiver over the UHF link. He was back out here in 2 days, and 3 work days after that every one of those poles had been rendered absolutely silent. 73, Paul On 01/05/2013 02:41 PM, Don Moman VE6JY wrote: Similar observations here Paul in my never ending battle to keep on top of the noise situation in my rural area - mainly 14.4 kv distribution and some 25kv 3 phase stuff. Many sources top out above 135 mhz but well below 450 so a yagi in between is certainly helpful. Like a ch 13 tv yagi or something for UHF mil aircraft. In the vehicle I often like to use an old (i.e. analogue and inexpensive) spectrum analyser like some of the portable Texscan CATV ones. Mine is the VSM-1 which covers up to 300 mhz so that coupled to a little whip on the vehicle is almost always enough to get you to the nearest pole or two as you drive by. The AVCOM PSA 65 I have is also OK but one wants something with a really wide RBW so you gather lots of the noise energy and in my experience the cheap and dirty Texscan gives me the best noise "bloom" as you drive by the pole. Depending on ambient light it can be tough to see the screen and still drive safely so fortunately they also have a wide band video out jack that can be used to drive a amp'd speaker. To zero in a bit closer I use the ICOM R-10 and a Create 50-1300 mhz log with the rear elements removed to make easier to get in the vehicle. It's "OK" but the pattern is not as nice as a single band yagi. But with this setup I can almost always tell the utility which pole is the culprit and they take it from there. I have some ultrasonic stuff and the power guy has the Radar Engineers unit - the hand held dish style and these are generally NOT helpful in finding much other than in maybe 1/3 of the cases confirming the findings that we are on the right pole. I think on many of the sources the arc is weak enough that there's not much ultrasonic energy. I have seen it not work enough that I wouldn't spend much energy or money on this route. The one ultrasonic device you want the power guys to have is the hot line sniffer from RE and that can (in their hands, not yours) pinpoint the exact hardware. The most challenging noise situation that I have experienced is the faulty transformer (all from brand new units) with a micro arc inside the can. TONS of LF noise around 80 and 160m but nothing at VHF, nothing ultrasonic as everything is in the can. And as you know, the noise at lower frequencies can travel a LONG way and you'll get noise peaks at corner structures etc, all trying to mislead you. When you don't see any obvious source in the normal fashion and there's still
Re: Topband: Another take on power line noise hunting
In the vehicle I often like to use an old (i.e. analogue and inexpensive) spectrum analyser like some of the portable Texscan CATV ones. As CATV companies have transitioned from NTSC to QAM channel line-ups, high quality field analysis meters have been showing up on the used market in big numbers. I recently acquired a used Wavetek SAM III Digital for about USD $100. Another great unit is the SAM I Analog. http://www.ham-radio.com/k6sti/sam.htm These units are excellent for localizing power line noise, especially when used with a scope to replicate the noise finding method recommended by Loftness and Radar Engineers. Dual AM and FM detectors, 480 MHz standard, 800 MHz optional, and tunes down to DC with lesser accuracy but fully useable for noise search. It also has a rechargeable battery, super-rugged field construction and a very high quality multi-step attenuator. A significant feature over other FSMs is that with a scope, it functions as a basic spectrum analyzer with reasonably good resolution bandwidth. Although the S/A function won't help to localize power line noise, it's a handy feature for secondary purposes. Not sure what these Wavetek units sold for new, but I would not be surprised if they were in the $2K+ area. Paul, W9AC ___ Stew Perry Topband Distance Challenge coming on December 29th.
Re: Topband: Another take on power line noise hunting
Similar observations here Paul in my never ending battle to keep on top of the noise situation in my rural area - mainly 14.4 kv distribution and some 25kv 3 phase stuff. Many sources top out above 135 mhz but well below 450 so a yagi in between is certainly helpful. Like a ch 13 tv yagi or something for UHF mil aircraft. In the vehicle I often like to use an old (i.e. analogue and inexpensive) spectrum analyser like some of the portable Texscan CATV ones. Mine is the VSM-1 which covers up to 300 mhz so that coupled to a little whip on the vehicle is almost always enough to get you to the nearest pole or two as you drive by. The AVCOM PSA 65 I have is also OK but one wants something with a really wide RBW so you gather lots of the noise energy and in my experience the cheap and dirty Texscan gives me the best noise "bloom" as you drive by the pole. Depending on ambient light it can be tough to see the screen and still drive safely so fortunately they also have a wide band video out jack that can be used to drive a amp'd speaker. To zero in a bit closer I use the ICOM R-10 and a Create 50-1300 mhz log with the rear elements removed to make easier to get in the vehicle. It's "OK" but the pattern is not as nice as a single band yagi. But with this setup I can almost always tell the utility which pole is the culprit and they take it from there. I have some ultrasonic stuff and the power guy has the Radar Engineers unit - the hand held dish style and these are generally NOT helpful in finding much other than in maybe 1/3 of the cases confirming the findings that we are on the right pole. I think on many of the sources the arc is weak enough that there's not much ultrasonic energy. I have seen it not work enough that I wouldn't spend much energy or money on this route. The one ultrasonic device you want the power guys to have is the hot line sniffer from RE and that can (in their hands, not yours) pinpoint the exact hardware. The most challenging noise situation that I have experienced is the faulty transformer (all from brand new units) with a micro arc inside the can. TONS of LF noise around 80 and 160m but nothing at VHF, nothing ultrasonic as everything is in the can. And as you know, the noise at lower frequencies can travel a LONG way and you'll get noise peaks at corner structures etc, all trying to mislead you. When you don't see any obvious source in the normal fashion and there's still plenty of noise then you have to start suspecting the transformer. Getting the utility to drop the primary is about the only way to tell. On the one case I was most familiar with they even listened with a mechanics stethoscope to the case but no arc noise. Keep in mind that many will NOT arc when the power is connected back on for several minutes or hours so don't let this mislead you. Obviously the utility doesn't want to change out a good transformer so don't let this trick you. And the new one could be bad, altho I haven't had that piece of bad luck - yet! Once the first bad transformer was identified and replaced, proving I was right, it became a LOT easier to convince them in future bad transformer cases. I have not used the o'scope much at all for noise signatures. I prefer to rebroadcast my noise from home on a very low power tx so I can hear it while I'm at the suspected source. It is easy to find all kinds of noise when we go looking around but one should focus on the noise that actually bothers you first. In a perfect world we'd like to clean up everything but with costs and manpower issues being a big issue with the utilities it's best to stay focused on the problems that affect you and save some good will and budget for the next one. 73 Don VE6JY On Sat, Jan 5, 2013 at 4:44 PM, N1BUG wrote: > I've been following this discussion with interest. I spent the summer > tracking down more than 20 sources of power line noise. As an offshoot of > that I've made it my mission to help clean up RFI in my little corner of > the world. I've been slowly drifting away from DXing and this has turned > out to be my new area of interest. > > Since this topic is perhaps of interest to topbanders, and since my > experiences seem to vary somewhat from the typical reported here so far, I > thought I would take a moment to share some observations. I should probably > note I was dealing with a mix of 13.2 kV distribution lines and 46 kV > transmission lines. My hunt was made more challenging by the fact I had > multiple sources in a relatively small area and could often hear more than > one at a time even with directional antennas and attenuation. > > My tools this summer were 135 MHz AM receiver with 3 element yagi and step > attenuator; LF/MF/HF/VHF/UHF AM receiver with DF loops for low bands and 7 > element yagi for 445 MHz; ultrasonic receiver with dish. > > Low frequencies, eg. AM BC or 160 meters were *occasionally* useful in > locating a general source area. Sometimes the area identified turned ou
Re: Topband: Another take on power line noise hunting
Hi Paul, You would helpful a step attenuator, in 1 dB steps, to be a valuable addition to your tool bag. There are situations where it helps isolate to an individual pole. Its much more accurate than an S-meter. Something like this, or many other alternatives: http://www.ebay.com/itm/Coaxial-RF-Step-Attenuator-Set-1-dB-steps-to-70-dB-total-DC-to-1-GHz-/200866468929?pt=LH_DefaultDomain_0&hash=item2ec4931441 73 Frank W3LPL Original message >Date: Sat, 05 Jan 2013 11:44:08 -0500 >From: N1BUG >Subject: Topband: Another take on power line noise hunting >To: Topband > >I've been following this discussion with interest. I spent the >summer tracking down more than 20 sources of power line noise. As an >offshoot of that I've made it my mission to help clean up RFI in my >little corner of the world. I've been slowly drifting away from >DXing and this has turned out to be my new area of interest. > >Since this topic is perhaps of interest to topbanders, and since my >experiences seem to vary somewhat from the typical reported here so >far, I thought I would take a moment to share some observations. I >should probably note I was dealing with a mix of 13.2 kV >distribution lines and 46 kV transmission lines. My hunt was made >more challenging by the fact I had multiple sources in a relatively >small area and could often hear more than one at a time even with >directional antennas and attenuation. > >My tools this summer were 135 MHz AM receiver with 3 element yagi >and step attenuator; LF/MF/HF/VHF/UHF AM receiver with DF loops for >low bands and 7 element yagi for 445 MHz; ultrasonic receiver with dish. > >Low frequencies, eg. AM BC or 160 meters were *occasionally* useful >in locating a general source area. Sometimes the area identified >turned out to be an area of *radiation* but the noise was >*generated* elsewhere. Often the relatively close proximity of >multiple sources made low frequency tracking useless. > >VHF was always useful in finding a source area, 80% of the time >resolving it to a single pole. The sharp, deep null at exactly 90 >degrees off axis of the yagi proved very useful for confirming a >source structure. Poor resolution/accuracy of signal strength >metering was perceived as a problem. > >UHF was very helpful in a few areas where the noise was particularly >strong at VHF and/or signal strength so close over a span of several >poles that VHF could not pick the source pole with high confidence. >So far, experience indicates this is more likely to happen on the >transmission lines. They're a bear. Again, poor or no signal >strength metering (signal below AGC threshold) was perceived as a >problem. > >The first ultrasonic unit tried was a waste, finding something at >only 10% of RF noisy poles. The second unit was able to hear >something from about 60% of the same 21 poles. The figures are >averages over more than 10 runs with each unit. The two were also >tested on a spark signal range under somewhat controlled conditions. >These things are definitely not created equal! > >To date I have identified and had the power company fix almost >everything I have worked on. The remaining open case involves a >short section of a 46 kV transmission line which is extremely >perplexing due to the specific nature of the issue (details on >request). Just when I starting thinking I was getting good at this, >I came up against this one. > >If I were doing this strictly for myself these tools would be more >than adequate. Since I'm not and I only have so many hours in a day >I have several upgrades on my wish list: > >HF/VHF/UHF AM receiver with wider bandwidth better signal strength >metering > >Log periodic dipole array covering ~100 to ~900 MHz for frequency >agility while maintaining some directional properties > >Portable oscilloscope for observing noise signatures in the field >(I'm hoping it helps sort out overlapping source radiations) > >Yet another upgrade of the ultrasonic unit. > >Comments are welcome, even if it's to tell me I'm clueless! :) > >73 >-- >Paul Kelley, N1BUG >RFI Committee chair, >Piscataquis Amateur Radio Club >http://www.k1pq.org >___ >Stew Perry Topband Distance Challenge coming on December 29th. ___ Stew Perry Topband Distance Challenge coming on December 29th.
Topband: Another take on power line noise hunting
I've been following this discussion with interest. I spent the summer tracking down more than 20 sources of power line noise. As an offshoot of that I've made it my mission to help clean up RFI in my little corner of the world. I've been slowly drifting away from DXing and this has turned out to be my new area of interest. Since this topic is perhaps of interest to topbanders, and since my experiences seem to vary somewhat from the typical reported here so far, I thought I would take a moment to share some observations. I should probably note I was dealing with a mix of 13.2 kV distribution lines and 46 kV transmission lines. My hunt was made more challenging by the fact I had multiple sources in a relatively small area and could often hear more than one at a time even with directional antennas and attenuation. My tools this summer were 135 MHz AM receiver with 3 element yagi and step attenuator; LF/MF/HF/VHF/UHF AM receiver with DF loops for low bands and 7 element yagi for 445 MHz; ultrasonic receiver with dish. Low frequencies, eg. AM BC or 160 meters were *occasionally* useful in locating a general source area. Sometimes the area identified turned out to be an area of *radiation* but the noise was *generated* elsewhere. Often the relatively close proximity of multiple sources made low frequency tracking useless. VHF was always useful in finding a source area, 80% of the time resolving it to a single pole. The sharp, deep null at exactly 90 degrees off axis of the yagi proved very useful for confirming a source structure. Poor resolution/accuracy of signal strength metering was perceived as a problem. UHF was very helpful in a few areas where the noise was particularly strong at VHF and/or signal strength so close over a span of several poles that VHF could not pick the source pole with high confidence. So far, experience indicates this is more likely to happen on the transmission lines. They're a bear. Again, poor or no signal strength metering (signal below AGC threshold) was perceived as a problem. The first ultrasonic unit tried was a waste, finding something at only 10% of RF noisy poles. The second unit was able to hear something from about 60% of the same 21 poles. The figures are averages over more than 10 runs with each unit. The two were also tested on a spark signal range under somewhat controlled conditions. These things are definitely not created equal! To date I have identified and had the power company fix almost everything I have worked on. The remaining open case involves a short section of a 46 kV transmission line which is extremely perplexing due to the specific nature of the issue (details on request). Just when I starting thinking I was getting good at this, I came up against this one. If I were doing this strictly for myself these tools would be more than adequate. Since I'm not and I only have so many hours in a day I have several upgrades on my wish list: HF/VHF/UHF AM receiver with wider bandwidth better signal strength metering Log periodic dipole array covering ~100 to ~900 MHz for frequency agility while maintaining some directional properties Portable oscilloscope for observing noise signatures in the field (I'm hoping it helps sort out overlapping source radiations) Yet another upgrade of the ultrasonic unit. Comments are welcome, even if it's to tell me I'm clueless! :) 73 -- Paul Kelley, N1BUG RFI Committee chair, Piscataquis Amateur Radio Club http://www.k1pq.org ___ Stew Perry Topband Distance Challenge coming on December 29th.
