Re: Topband: RFI - lots of it
Thanks Tom. I think I have it narrowed down with a portable. The line going to our home is spliced to the main line along with another line going to a building across the highway. At that spot there is a ball of wires with some kind of what appears to be a metal fixture (clamp etc.). Just not familiar with hardware used. Noise drops at building across the highway around the meter etc. and down the main line in both directions. Noise just below the junction is loudest I could find. Thanks to all the good people on the forum I've accumulated a folder of RFI, grounding and bonding info that I'm sure contain the solution. One lesson learned is to check 160 before you start laying in radials etc. I didn't have an antenna that I could tune that low. At our old qth I left a nice radial system and moved here last fall and spent the summer working on another radial system. What's ironic is that the power company put in a new feed line to the house since they said the old one was corroding copper etc.. They did it for free as long as we would replace the meter and line to the main panel, which we did. The ironic part is they left me the old wire and I used it for one of the radials:). I think it weighed 20 pounds, all copper. Regards,jim/k2hn Wet weather noise is often corona related, but sometimes defective insulators, cracked, scored, or dirty. I had problems with 345kV line corona in Ohio when the weather was damp. Dry weather noise is often slack spans allowing the metal pin joints or ball and socket joints in insulators to arc from capacitive coupling. The metal on metal corrodes and makes a tiny layer of oxide that arcs from capacitive coupling and leakage. Hitting a pole with a hammer finds that, because it shakes the wires and wiggles the metal joints. There are so many different things that can cause noise, however, that any Internet diagnosis is mostly a wild guess. The best thing to do before doing anything is try to track it with a VHF AM radio, like a portable aircraft radio. I have commercial noise locating equipment, but the last time I lent it out it came back broken. :( 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: RFI - Lots of it
Jim - Is this noise on 160M only, or all ham bands? Is 160M the worst, but all bands afflicted? You said your noise blanker works well on the noise, which is one clue. Another thing you can do: Turn off the noise blanker, go to the part of the band that has the worst noise, and set your rig for AM reception on the widest bandwidth you have. Put the resulting audio on a scope or feed into a computer and make a scope trace using audacity. Zoom in and see if the noise really is 120Hz spikes. If it is 120Hz spikes, then it is utility related (not necessarily the utility's hardware, could also be customer side stuff). If instead you have whiny noises all over 160M, then it is likely from a switching power supply somewhere in your area or a dog fence, and not going to be resolved directly by the utility. If you have 120Hz spikes audible on AM afflicting 160M, then you can just drive around with your car's AM radio near the top of the AM band and get some idea of the affected area. When you get close you to an offending pole you may find that higher frequencies are also afflicted, and may even affect FM reception. If you have a HT that has AM mode, it will go nuts when you are right under the bad pole. I have been afflicted with 120Hz utility impulse noise many times, and every time the local utility has been able to track down (not so fast) and then repair the offending pole (surprisingly fast.) Different bands have been afflicted each time. In several of the worst cases after finding the offending poleIu can hear the buzz of something arcing overhead with my ears when standing near the pole. Tim N3QE On Sun, Oct 25, 2015 at 6:13 PM, Jim Murray via Topband < topband@contesting.com> wrote: > Greetings,Last Fall we moved into a new location. This Summer I spent a > lot of time and effort putting up an Inverted L and radial system. Now > after tuning, etc. completed I have what appears to be power line noise, > source unknown at this time. I threw the main in our home and noise still > remained. The closer I get to the power lines or the antenna system the > louder it gets. As I jump in freq., the higher the band the less noise. I > have a portable receiver that is capable of rx on the ham bands. As it > sits right now 160 is just about out of the question. Rig is a ft1000mp > mk5 field and the NB does do a good on the noise but also on the weak > signals. This is the first location in 35 years that I've run into this. > I don't have much faith at this point in the power company finding the > source but will call them this week. Any ideas would be greatly > appreciated and also wondering about Noise Phasing with MFJ-1025. I read > w8ji article on it but not sure if it would help on noise of this > magnitude.Regards,jim/k2hn > _ > Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: RFI - Lots of it
Jim, Did you power down the battery backup for in-house systems such as your security system and cable modem and routers? Mike N2MS - Original Message - From: Jim Murray via Topband To: topband@contesting.com Sent: Sun, 25 Oct 2015 22:13:45 - (UTC) Subject: Topband: RFI - Lots of it Greetings,Last Fall we moved into a new location. This Summer I spent a lot of time and effort putting up an Inverted L and radial system. Now after tuning, etc. completed I have what appears to be power line noise, source unknown at this time. I threw the main in our home and noise still remained. The closer I get to the power lines or the antenna system the louder it gets. As I jump in freq., the higher the band the less noise. I have a portable receiver that is capable of rx on the ham bands. As it sits right now 160 is just about out of the question. Rig is a ft1000mp mk5 field and the NB does do a good on the noise but also on the weak signals. This is the first location in 35 years that I've run into this. I don't have much faith at this point in the power company finding the source but will call them this week. Any ideas would be greatly appreciated and also wondering about Noise Phasing with MFJ-1025. I read w8ji article on it but not sure if it would help on noise of this magnitude.Regards,jim/k2hn _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: RFI- lots of it
Thanks Cecil,Yes during daylight hours also. _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: RFI - Lots of it
Jim, At each location where I have lived, I have had line noise problems. It turns out that the main culprit has been the insulators on the pole were either dirty or cracked by lightning or loose hardware. If they are really old, they may have a ball and socket connection that is *supposed* to conduct electricity without creating noise. These usually show up in windy conditions. Hardware can also get rusty which can cause multiple problems. Be sure not to overlook lightning arrestors and fuses on the pole. The experience here is that if you can find the pole where the problem is, the electric company seems to be more corporative. I usually used a 3 lb. hammer to hit the pole and the noise sometimes acts up or gets better depending on the problem. Many around here, jerk on the guy line to wiggle the pole, but that can be a risky adventure because you never know what that could come apart and there you are holding onto a wire. Ask them to replace any hardware that is faulty and try not to let them just clean it, that *never* lasts. You might call and ask to talk to the person that takes care of these problems. They may have equipment that they can use to pinpoint it. Lately they have been using microwave frequency receivers with a dish antenna that has a very narrow beam width to locate the problem. You also have more than one source; this makes it especially difficult for some noise blankers to work. Jim - KR9U -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Jim Murray via Topband Greetings,Last Fall we moved into a new location. This Summer I spent a lot of time and effort putting up an Inverted L and radial system. Now after tuning, etc. completed I have what appears to be power line noise, source unknown at this time. I threw the main in our home and noise still remained. The closer I get to the power lines or the antenna system the louder it gets. As I jump in freq., the higher the band the less noise. I have a portable receiver that is capable of rx on the ham bands. As it sits right now 160 is just about out of the question. Rig is a ft1000mp mk5 field and the NB does do a good on the noise but also on the weak signals. This is the first location in 35 years that I've run into this. I don't have much faith at this point in the power company finding the source but will call them this week. Any ideas would be greatly appreciated and also wondering about Noise Phasing with MFJ-1025. I read w8ji article on it but not sure if it would help on noise of this magnitude.Regards,jim/k2hn _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: RFI - Lots of it
On Sun,10/25/2015 3:13 PM, Jim Murray via Topband wrote: This Summer I spent a lot of time and effort putting up an Inverted L and radial system. An important part of moving to a new QTH is grounding and bonding. One of the things I did in my professional life was teach grounding and bonding to audio and video professionals. Here's my tutorial on the topic focusing on techniques applicable to ham radio. http://k9yc.com/GroundingAndAudio.pdf I moved into a new QTH 10 years ago. It was out in the country, but it was very noisy. Over the following year or so, I discovered that grounding and bonding was a disaster -- it violated very rule in the book. Once I corrected those fundamental errors, it's now pretty quiet most of the time. 73, Jim K9YC _ Topband Reflector Archives - http://www.contesting.com/_topband
