AC Pole Interference
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Hello fellow K3 Owners. I have finally discovered that AC Interference from the pole across the street is getting into my antenna and then of course I see it on my S-meter on the K3. On Saturday I had this interference all day and I finally went out with a portable AM Radio and found out that it was that particular pole. What's amazing is that at 10:15 PM the noise was gone and I went out to the pole again with my AM radio and the noise was gone. I have reported this to Philadelphia Electric Company. But the problem is that the interference is sporadic in nature and doesn't happen all the time.
Does anyone know if there is a filter that one can hook up to there antenna that would eliminate this interference before it gets into my K3? When I don't have the interference HF is a wonderfull thing, but when I have the interference I get a lousy S-5 to S-7 reading on my S-Meter. And suggestions would be much appreciated!! Mark KB3Z ------------------------------ Sent using Verizon.net Mobile ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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Have you tried all the K3's NB settings? I would be surprised if the K3's NB does not at least cut some of the interference down. I have seen some pretty brutal noise at my QTH on occasion and the NB always seems to at least chop some of it out to provide a readable signal. I have eliminated a S9 noise levels on 40M and be able to read a weak CW signal, where w/o the NB, you would not even know the signal was there.
Roger W6RDW
Roger W5RDW
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In reply to this post by pastormg
On Mon, Nov 21, 2011 at 9:57 AM, [hidden email] <
[hidden email]> wrote: > ...found out that it was that particular pole. What's amazing is that at > 10:15 PM the noise was gone... ======= I had a similar situation. Unfortunately, the problem wasn't with the pole. It was some neighbor's appliance whose hash was being re-radiated from the pole. Neither I nor the power company could ever figure it out. However, if it is something loose on the pole, you may be able to verify it by whacking the pole with a sledge hammer (seriously). If that makes the noise start and stop, you can prove it to the electric company guy when/if he comes out. Good luck. Noise is the frustrating bane of the HF op. 73, Tony KT0NY ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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Seriously wrong move. Several reasons: The pole is the utility company's property, not yours. If "whacking" the pole causes any sort of damage, you are liable, for both direct costs and and damages caused to other users due to your actions. It is dangerous. Electrical noise can be caused by failing hardware on the pole. Assaulting the pole could cause the entire pole, or anything connected to it, to fail completely, dropping live wires on you or others - again with serious consequences. Also, if someone from the utility company discovers your activities, they can reasonably claim your actions were the cause of any failures associated with the pole for years to come. Not kidding about this - it can happen. Report your suspicions to the utility company, that's for sure, but stop there. Let them fix it. If they don't act in a reasonable time (2 weeks to 30 days max), then you can call in the FCC. They WILL help you, but like any government agency, it may take a while. Better results may be obtained if other neighbors are having problems with interference to their TV or radio reception. Several complaints from different sources will cause faster action. - Jim, KL7CC Tony Estep wrote: > However, if it is something loose on the pole, you may be able to verify it > by whacking the pole with a sledge hammer (seriously). If that makes the > noise start and stop, you can prove it to the electric company guy when/if > he comes out. > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by pastormg
Hi Mark,
> Hello fellow K3 Owners. I have finally discovered that AC Interference > from the pole across the street is getting into my antenna and then of > course I see it on my S-meter on the K3. On Saturday I had this > interference all day and I finally went out with a portable AM Radio and > found out that it was that particular pole. What's amazing is that at > 10:15 PM the noise was gone and I went out to the pole again with my AM > radio and the noise was gone. I have reported this to Philadelphia > Electric Company. But the problem is that the interference is sporadic in > nature and doesn't happen all the time. > http://www.w8ji.com/power_line_noise.htm any of that look like your pole? > Does anyone know if there is a filter that one can hook up to there > antenna that would eliminate this interference before it gets into my K3? > When I don't have the interference HF is a wonderfull thing, but when I > have the interference I get a lousy S-5 to S-7 reading on my S-Meter. And > suggestions would be much appreciated!! Mark KB3Z No. Noise of short pulse width and low duty cycle can be blanked, but any noise reduction, other than phase cancelation methods, always causes a penalty on receiving. It is best to fix it at the source. 73 Tom ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by pastormg
Mark,
If you noise source is in one main direction which it sounds like then the MFJ 1026 noise canceler works wonders. If it is coming from other directions too then it wouldn't be the ticket. I have used the 1026 to null out the noise from an offending power pole that is about 100 yards from my house. My noise was about s8 to s9plus with spikes. Operating on CW with a narrow filter setting and finding the best NB and NR settings on my K3 gave me reasonable results on reducing the noise enough to copy DX CW. Very weak CW sigs were still impaired however. I had our power company come out two times to remedy the noise situation. When they came out the noise wasn't there (naturally) my noise was intermittent like yours. I purchased the 1026 and successfully used it to combat the noise. In the mean time I decided to do some detective work on my noise situation myself hoping to show the power company the source myself. I have a Kenwood handheld that receives the aircraft AM band and I have a 4 element 2 meter beam unused so I clamped the beam on a one foot long wood round bar and velcroed the handheld to the bar. I was able to zero in quite easily to the offending pole aiming the 2 meter beam and walking back and forth. ( I was a source of entertainment for my neighbors, hihi.) I called the power company and told them I had located the noise source with my specialized RFI equipment ( I had to tell them something to get them out here again. hihi) and would like to show them if they could come out. The power company technician came out and as luck would have it the noise was there when the was there ! He was impressed with the zeroing in with my set up. I had narrowed it down to the offending pole but couldn't zero in any closer. He had a small hand held dish and noise receiver combo with him and was able to pinpoint the source even closer. Some of the old hardware was arcing. He put in a ticket and 2 weeks later the hardware was replaced on this pole. Noise went away ! Now I have another new source of noise coming from our city park in the opposite direction. (it never ends) Not as bad as the previous source but with a little luck I can eliminate it also. Your situation may be different than mine but if the noise is coming from one direction it is a lot easier to deal with. (Using the MFJ 1026 for instance.) What I would do first is to make sure it isn't coming from inside your home. Run your HF rig off a 12 volt battery temporarily and shut off the main breaker to the house. Then if it still is there, take a portable radio that receives AM and start walking around your neighbor hood noting the signal strength of the noise. The power lines act as antennas for radiating the noise so it will be carried for quite a ways down the lines. Hopefully you will find the noisy pole which will be much louder than the rest. If you have a handheld with the Aircraft AM band I would use it even with the rubber duck antenna. The radiated noise doesn't carry as far on VHF so you will be able to narrow it down easier to the offending pole. It could be coming from a neighbors house also, the AM portable radio approach is good in either case to start your sleuthing. Good luck on solving your noise problem. Hope this helps a little. 73, Bob K6UJ On Nov 21, 2011, at 7:57 AM, [hidden email] wrote: > Hello fellow K3 Owners. I have finally discovered that AC Interference from the pole across the street is getting into my antenna and then of course I see it on my S-meter on the K3. On Saturday I had this interference all day and I finally went out with a portable AM Radio and found out that it was that particular pole. What's amazing is that at 10:15 PM the noise was gone and I went out to the pole again with my AM radio and the noise was gone. I have reported this to Philadelphia Electric Company. But the problem is that the interference is sporadic in nature and doesn't happen all the time. > > Does anyone know if there is a filter that one can hook up to there antenna that would eliminate this interference before it gets into my K3? When I don't have the interference HF is a wonderfull thing, but when I have the interference I get a lousy S-5 to S-7 reading on my S-Meter. And suggestions would be much appreciated!! Mark KB3Z > > ------------------------------ > Sent using Verizon.net Mobile > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by pastormg
Mark,
Your utility company knows about intermittent noise from their poles. They should be on top of your complaint and you really should not have to provide anything yourself if the pole in questions is for sure the culprit. Noisy insulators on utility poles can change from time to time during the day and usually follow warm or moist conditions pretty predictably. Give PEC time to do their thing. The FCC requires it of them. 73, Terry, W0FM -----Original Message----- From: [hidden email] [mailto:[hidden email]] Sent: Monday, November 21, 2011 9:58 AM To: [hidden email] Subject: [Elecraft] AC Pole Interference Hello fellow K3 Owners. I have finally discovered that AC Interference from the pole across the street is getting into my antenna and then of course I see it on my S-meter on the K3. On Saturday I had this interference all day and I finally went out with a portable AM Radio and found out that it was that particular pole. What's amazing is that at 10:15 PM the noise was gone and I went out to the pole again with my AM radio and the noise was gone. I have reported this to Philadelphia Electric Company. But the problem is that the interference is sporadic in nature and doesn't happen all the time. Does anyone know if there is a filter that one can hook up to there antenna that would eliminate this interference before it gets into my K3? When I don't have the interference HF is a wonderfull thing, but when I have the interference I get a lousy S-5 to S-7 reading on my S-Meter. And suggestions would be much appreciated!! Mark KB3Z ------------------------------ Sent using Verizon.net Mobile ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Bob K6UJ
I've used the MFJ-1026 combined with the NB/NR in the K3 to greatly
reduce all kinds of strange noise from the city. Often I need to start with the MFJ-1026, to null out as much as possible and then I hit the NB to get the rest. It's a fairly powerful combination. On Mon, Nov 21, 2011 at 9:33 AM, Bob K6UJ <[hidden email]> wrote: > Mark, > > If you noise source is in one main direction which it sounds like then the MFJ 1026 noise canceler works wonders.  If it is coming from > other directions too then it wouldn't be the ticket. > I have used the 1026 to null out the noise from an offending power pole that is about 100 yards from my house.  My noise was about s8 to s9plus > with spikes.  Operating on CW with a narrow filter setting and finding the best  NB and NR settings on my K3 gave me reasonable results > on reducing the noise enough to copy DX CW.  Very weak CW sigs were still impaired however. > I had our power company come out two times to remedy the noise situation.  When they came out the noise wasn't there (naturally) my noise was > intermittent like yours.  I purchased the 1026 and successfully used it to combat the noise.  In the mean time I decided to do some detective work > on my noise situation myself hoping to show the power company the source myself.  I have a Kenwood handheld that receives the aircraft AM band > and I have a 4 element 2 meter beam unused so I clamped the beam on a one foot long wood round bar and velcroed the handheld to the bar. > I was able to zero in quite easily to the offending pole aiming the 2 meter beam and walking back and forth. ( I was a source of entertainment for my neighbors, hihi.) > I called the power company and told them I had located the noise source with my specialized RFI equipment ( I had to tell them something to get them out here again. hihi) >  and would like to show them if they could come out. > The power company technician came out and as luck would have it the noise was there when the was there !  He was impressed with the zeroing in with > my set up.  I had narrowed it down to the offending pole but  couldn't zero in any closer.  He had a small hand held dish and noise receiver combo with him and > was able to pinpoint the source even closer.  Some of the old hardware was arcing.  He put in a ticket and 2 weeks later the hardware was replaced on this pole. > Noise went away ! > Now I have another new source of noise coming from our city park in the opposite direction. (it never ends)  Not as bad as the previous source but  with a little > luck I can eliminate it also. >  Your situation may be different than mine but if the noise is coming from one direction it is a lot easier to deal with. > (Using the MFJ 1026 for instance.)  What I would do first is to make sure it isn't coming from inside your home.  Run your HF rig off a 12 volt battery temporarily > and shut off the main breaker to the house.  Then if it still is there, take a portable radio that receives AM and start walking around your neighbor hood noting the > signal strength of the noise.  The power lines act as antennas for radiating the noise so it will be carried for quite a ways down the lines.  Hopefully you will find the noisy > pole which will be much louder than the rest.  If you have a handheld with the Aircraft AM band I would use it even with the rubber duck antenna.  The radiated noise doesn't carry as far  on VHF so you will be able to narrow it down easier to the offending pole.  It could be coming from a neighbors house also,  the AM portable radio approach is good > in either case to start your sleuthing. > Good luck on solving your noise problem.  Hope this helps a little. > > 73, > Bob > K6UJ > > > > > On Nov 21, 2011, at 7:57 AM, [hidden email] wrote: > >> Hello fellow K3 Owners.  I have finally discovered that AC Interference from the pole across the street is getting into my antenna and then of course I see it on my S-meter on the K3.  On Saturday I had this interference all day and I finally went out with a portable AM Radio and found out that it was that particular pole.  What's amazing is that at 10:15 PM the noise was gone and I went out to the pole again with my AM radio and the noise was gone.  I have reported this to Philadelphia Electric Company.  But the problem is that the interference is sporadic in nature and doesn't happen all the time. >> >> Does anyone know if there is a filter that one can hook up to there antenna that would eliminate this interference before it gets into my K3?  When I don't have the interference HF is a wonderfull thing, but when I have the interference I get a lousy S-5 to S-7 reading on my S-Meter.  And suggestions would be much appreciated!!  Mark KB3Z >> >>       ------------------------------ >>       Sent using Verizon.net Mobile >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > -- ------------------------------------------- Owner, worldwidedx.com AE6LX, Amateur Radio NNN0ITA, Navy MARS NNN0GAF FOUR, Southern CA Training Director, Navy MARS ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Jim Wiley-2
Jim I might agree with you except whacking poles is an industry standard
method. (It gives you some sort of manly satisfaction too.) I have seen the power company do it. If the pole is so fragile that whacking it causes a problem it needs to be replaced anyway. Better to do it when the sun is shining than when the storm is raging. I have heard some companies use pole shakers but I have never seen one. Some utility districts are very responsive to RFI complaints and other districts within the same company will just blow you off. You will get much better results if you tell them 'I see sparks up there when the wind blows' than 'You have an RFI problem'. One problem I have seen that is easy to fix is the ground coming down the pole for the transformer. You can sometimes spot them by visual inspection. Point it out to the power company and they will jump on it. 73 Fred, AE6QL -----Original Message----- From: [hidden email] [mailto:[hidden email]] On Behalf Of Jim Wiley Sent: Monday, November 21, 2011 8:38 AM To: Tony Estep Cc: [hidden email] Subject: Re: [Elecraft] AC Pole Interference Seriously wrong move. Several reasons: The pole is the utility company's property, not yours. If "whacking" the pole causes any sort of damage, you are liable, for both direct costs and and damages caused to other users due to your actions. It is dangerous. Electrical noise can be caused by failing hardware on the pole. Assaulting the pole could cause the entire pole, or anything connected to it, to fail completely, dropping live wires on you or others - again with serious consequences. Also, if someone from the utility company discovers your activities, they can reasonably claim your actions were the cause of any failures associated with the pole for years to come. Not kidding about this - it can happen. Report your suspicions to the utility company, that's for sure, but stop there. Let them fix it. If they don't act in a reasonable time (2 weeks to 30 days max), then you can call in the FCC. They WILL help you, but like any government agency, it may take a while. Better results may be obtained if other neighbors are having problems with interference to their TV or radio reception. Several complaints from different sources will cause faster action. - Jim, KL7CC Tony Estep wrote: > However, if it is something loose on the pole, you may be able to verify it > by whacking the pole with a sledge hammer (seriously). If that makes the > noise start and stop, you can prove it to the electric company guy when/if > he comes out. > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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> Jim I might agree with you except whacking poles is an industry standard
> method. (It gives you some sort of manly satisfaction too.) I have seen > the > power company do it. When I ran the difficult noise problems for a few utility companies, that indeed was a standard method for finding loose hardware. The only really dangerous thing was shaking a pole by pulling on a guy line. :-) This does not mean a non-employee should do it. I have seen a whack start a fire though, when a loose hot clamp dropped molten metal. That also hurts the top of your head, or your eye. :-) The best idea is to not mess with their property. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Tony Estep
"...whacking the pole with a sledge hammer..." - Seriously! In a presentation last September by noise expert K3RFI, he STRONGLY urged people not do this. It is DANGEROUS!! If there IS loose hardware and you whack the pole that hardware could come down on you...and maybe along with some hot conductors. 73, Ted W4NZ -----Original Message----- From: [hidden email] [mailto:[hidden email]]On Behalf Of Tony Estep Sent: Monday, November 21, 2011 11:23 AM To: [hidden email] Subject: Re: [Elecraft] AC Pole Interference On Mon, Nov 21, 2011 at 9:57 AM, [hidden email] < [hidden email]> wrote: > ...found out that it was that particular pole. What's amazing is that at > 10:15 PM the noise was gone... ======= I had a similar situation. Unfortunately, the problem wasn't with the pole. It was some neighbor's appliance whose hash was being re-radiated from the pole. Neither I nor the power company could ever figure it out. However, if it is something loose on the pole, you may be able to verify it by whacking the pole with a sledge hammer (seriously). If that makes the noise start and stop, you can prove it to the electric company guy when/if he comes out. Good luck. Noise is the frustrating bane of the HF op. 73, Tony KT0NY ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Tony Estep
On 11/21/2011 8:22 AM, Tony Estep wrote:
> I had a similar situation. Unfortunately, the problem wasn't with the pole. > It was some neighbor's appliance whose hash was being re-radiated from the > pole. Neither I nor the power company could ever figure it out. YES! I've seen the same thing. Trash is very often generated by electronics, and by the power supplies for electronics, in a building, carried to the AC power line (made worse if the home is poorly grounded), and radiated by the power line. If the home IS well grounded, radiation of the trash is primarily limited to the wiring inside the home (and to outside wiring like telephone, CATV, and satellite TV cables). . 73, Jim Brown K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by W8JI
On 11/21/2011 11:04 AM, Tom W8JI wrote:
> When I ran the difficult noise problems for a few utility companies, that > indeed was a standard method for finding loose hardware. The only really > dangerous thing was shaking a pole by pulling on a guy line.:-) > > This does not mean a non-employee should do it. I have seen a whack start a > fire though, when a loose hot clamp dropped molten metal. That also hurts > the top of your head, or your eye.:-) I agree. There's also the matter of HOW you whack the pole. Many years ago, I spent time on a service bench fixing things, and later spent time doing field service. Banging on things can be a good way to find intermittent problems, but HOW and WHERE you choose to do your banging can be a bit of an art. 73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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For 36 years, I worked as a "pole engineer" for a large municipal
electric utility. When I was new at the job, my boss got a call from a concerned citizen. He was told that a young feller (that was 1969) driving a city car was banging on poles with an ax and drilling holes near the ground. My boss said "good"! Meant that I wasn't down at the Tug Tavern getting rehydrated! We were taught to "sound' the poles and listen for for the pole to "ring". Rot in the upper sections of the pole doesn't support vibrations and has a dead sound. And we drilled into the "rot zone" just below the ground line with 18 inch "bell hanger bits". This is definitely "a hard hat zone", but I never had anything other than old bird dropping dust and wood flakes "rain" down on me! I learned to step back and not look up after delivering a good blow with the back side of my ax. A lot of cyclic noise from poles actually comes from defective street lights. They make noise when they start up, and some lights cycle off and on every few minutes. This can be quite strong for several blocks. In the "old days", we had two technicians with a well equipped van to locate radio noise. Their jobs got eliminated in budget cuts. Complaints were handled on a "hit and miss" basis after that by employees with little training and equipment. 73, Rick Dettinger K7MW > > I agree. There's also the matter of HOW you whack the pole. Many > years > ago, I spent time on a service bench fixing things, and later spent > time > doing field service. Banging on things can be a good way to find > intermittent problems, but HOW and WHERE you choose to do your banging > can be a bit of an art. > > 73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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> inch "bell hanger bits". This is definitely "a hard hat zone", but I
> never had anything other than old bird dropping dust and wood flakes > "rain" down on me! I learned to step back and not look up after > delivering a good blow with the back side of my ax. I used a big sledge hammer. I cannot imagine having something break or fall, other than small junk. The very worse I caused was a loose hot clamp showering molten metal that started a grass fire. I think the real concern is small junk falling, but after that experience with the loose hot clamp I realized molten copper could be a problem. That thing eventually would have burned right through the primary, and the primary would have dropped. 73 Tom ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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Poor connection in hot line clamps used for taps off a main line or for
equipment connections, etc. are notorious for causing RF noise as well as creating fires and shock hazards in situations like Tom mentions. Hot line clamps are used where it is not cost effective to install disconnect switches. The older hot line clamps did not have spring loading, and in time, with wind vibration, the clamps had a tendency to loosen. Three things have been done to mitigate this problem of burning a tensioned conductor in two. 1. Hot line clamps now have spring loading. 2. Hot line clamps typically have a dab of oxide inhibitor in the mouth of the clamp as it comes from the factory. 3. Most utilities crimp install a "Saddle" loop on the conductor, and then connect the hot line clamp to the saddle. Then, if the hot line clamp connection fails it only burns the saddle loop, and not the tensioned conductor. Mis dos centavos, de Milt, N5IA -----Original Message----- From: Tom W8JI Sent: Tuesday, November 22, 2011 11:22 AM To: Rick Dettinger ; [hidden email] Cc: [hidden email] Subject: Re: [Elecraft] AC Pole Interference I think the real concern is small junk falling, but after that experience with the loose hot clamp I realized molten copper could be a problem. That thing eventually would have burned right through the primary, and the primary would have dropped. 73 Tom ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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There were persistent rumors that some of our lineman intentionally
left a few of the hot line clamps loose, to enhance the overtime pay when the wind blew hard, like last night in western Washington! 73, Rick K7MW On Nov 22, 2011, at 10:45 AM, Milt -- N5IA wrote: > Poor connection in hot line clamps used for taps off a main line or > for equipment connections, etc. are notorious for causing RF noise > as well as creating fires and shock hazards in situations like Tom > mentions. > > Hot line clamps are used where it is not cost effective to install > disconnect switches. > > The older hot line clamps did not have spring loading, and in time, > with wind vibration, the clamps had a tendency to loosen. > > Three things have been done to mitigate this problem of burning a > tensioned conductor in two. > > 1. Hot line clamps now have spring loading. > > 2. Hot line clamps typically have a dab of oxide inhibitor in the > mouth of the clamp as it comes from the factory. > > 3. Most utilities crimp install a "Saddle" loop on the conductor, > and then connect the hot line clamp to the saddle. Then, if the hot > line clamp connection fails it only burns the saddle loop, and not > the tensioned conductor. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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