Any one dealt with strong local RF interference. I am getting 15 to 20 over QRM on 80 meters. Unless someone has a very strong signal, I cannot hear them. Commercial AM radio is also affected for a three block area bordering my location. Comments or suggestions?
Local RF Interference
- Thread starter CWS
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Happy fox hunting as its called. The trick will be operating down in the 80m region, where conventional antennas are too big and bulky up use for direction finding.
A quick search of the topic, e.g. "80m ARDF" shows that there are some kits and radios, including Chinese ones, that can be used for direction finding at these frequencies. Basically, it looks like they wrapped a coil of antenna around a ferrite core to get it to operate at these frequencies and provide a directional null.
The good news is that if you can find the source, the FCC is in your side in terms of eliminating the interference, but it's recommended to try the courteous approach before engaging them.
A quick search of the topic, e.g. "80m ARDF" shows that there are some kits and radios, including Chinese ones, that can be used for direction finding at these frequencies. Basically, it looks like they wrapped a coil of antenna around a ferrite core to get it to operate at these frequencies and provide a directional null.
The good news is that if you can find the source, the FCC is in your side in terms of eliminating the interference, but it's recommended to try the courteous approach before engaging them.
I'm not an expert, by far, on this but I will relate a story...
Back around '83 I move into a house that had bad TV reception. I ran cable inside and had the local cable company hook it up. Fast forward 1 year or so. I get a knock on the door and it's the FAA-WhateverBranchOfEnforcement (commercial airport 5 miles away in the next town). Seems they have had complaints from planes about interference in this area and tracked it to my house. They asked to come in and scan.
They found a bad terminator on a coax splitter. They put a terminator on it and grounded the splitter. Problem solved. I always thought that was weird.
Back around '83 I move into a house that had bad TV reception. I ran cable inside and had the local cable company hook it up. Fast forward 1 year or so. I get a knock on the door and it's the FAA-WhateverBranchOfEnforcement (commercial airport 5 miles away in the next town). Seems they have had complaints from planes about interference in this area and tracked it to my house. They asked to come in and scan.
They found a bad terminator on a coax splitter. They put a terminator on it and grounded the splitter. Problem solved. I always thought that was weird.
OP
No electric fences; and I have eliminated any sources in the house. (Hooked the transceiver to a 12 volt battery and systematically turned off each breaker in the house). I think that I have identified a few power poles in the neighborhood as the problem. Utilities are provided by the city, and I have contacted them. They have been less than helpful, and stated that unless I could identify the source and prove that it was the problem, that they would not even investigate it. The person I talked to has been on vacation this week. I will talk with him again on Monday.
Power poles with uninsulated steel staples on copper ground wires will cause a galvanic broadband emission. You may have the ground wire on a telephone pole radiating. The power company has insulated staples they use just for this reason. My power company, Union Electric, is very responsive to radio noise complaints. They once replaced a transformer and all the staples on about 1/2 mile of line behind my house and it fixed my HF noise issues.
I'd suggest getting some of the local AM stations engaged (ask for station engineer) and tell them you can't listen because there's some bad noise JUST in your area. While the FCC may ignore you, they're less likely to ignore 4-5 AM commercial stations.
A handheld "transistor" radio will help with its directional bar magnet.
A handheld "transistor" radio will help with its directional bar magnet.
OP
Reply to Htperry and John: Howard, I think that you may be right about the ground lines as at least part of the problem. I borrowed an MFJ Ultrasonic Receiver from our local club. I can identify specific power poles that seem to be problematic. When I put the receiver close to the ground wires, it goes wild.
John, thanks for the idea of getting the local radio station involved. That may help a lot. I am expecting a call from the City of Albemarle utilities dpt. on Monday. The guy that I need to talk to has been on vacation. I am hoping for good results from that.
Thanks for all of the responses. Any other thoughts or suggestions would be more than welcomed.
John, thanks for the idea of getting the local radio station involved. That may help a lot. I am expecting a call from the City of Albemarle utilities dpt. on Monday. The guy that I need to talk to has been on vacation. I am hoping for good results from that.
Thanks for all of the responses. Any other thoughts or suggestions would be more than welcomed.
OP
Update on local RF. The city sent a truck out to check on the poles that I had identified. They found that a bat had hit a wire near a contact, and been killed. As the bat decomposed, the body corroded a contact on the pole. That was apparently the cause of the interference that covered between a quarter and a half mile. The RF is no longer a problem.
Thanks again for suggestions.
Thanks again for suggestions.