Putting Noise to Bed -- Foxhunt Adventure

For the past year I have experienced a ticking or popping sound on all bands from 20 meters through 6 meters. These annoying noise could be heard equally as well on my FT-1000MP Mark V, IC-756ProII and TS-2000 receivers. The noise varied in signal strength depending on frequency and atmospheric conditions. Sometimes I could hear it on 20 meters and other times barely at all. It was always present on 10 meters and 6 meters. Recently, I bought a new Icom IC-7800 and the noise persisted with no help from the noise blanker or DSP noise reduction. It seemed nothing could eliminate this noise. I was determined to find the source and eliminate it myself.

I had taken many steps in attempting to isolate this problem. I won't bore you with all of the details, however, I will share with you the most recent steps taken to isolate the problem and my findings, which are extraordinary.

After shutting down the power to EVERY breaker in my home EXCEPT the dedicated circuits with isolated grounds that power my transceivers, I finally came to the conclusion that the interference was not being generated by any device in my home. In fact, I even removed the batteries from every device in my home including battery operated sprinkler timers outside my home. Having four young children, I can assure you that is a lot of batteries.

It was a very frustrating and time consuming process, and it certainly didn't make my wife or children very happy while power was being shut off and restored throughout the home. I did try to do most of this testing while they were out of the house, but the length of time that it took to isolate this issue was significant.

After discovering that not a single electrical device in my home was causing this extremely annoying noise, I decided it must be an electrical problem somewhere else and the electric company seemed like the most likely source.

I had recently purchased an M2 6M5X yagi for 50Mhz and found that when I pointed the yagi northeast towards Europe, the noise was strongest. I finally had something to work with, a direction! Interestingly, this direction was pointing exactly at my GAP vertical 100 yards away.

Fortunately, during our last trip to Dayton, we purchased my oldest son an Icom IC-R3 receiver which would make an excellent noise tracking receiver in AM mode.

First, I set the IC-R3 to 28.5Mhz, where the noise was the strongest on my transceivers, then selected the AM mode. I could not hear the noise! Wow, was I disappointed. I knew the noise was there and I knew what direction it was coming from so I preceded to walk out toward the GAP antenna, following the direction my 50Mhz beam was pointing. Upon arrival at the GAP, still nothing! I couldn't believe my ears. I simply could not hear the noise! I went back to the shack, turned on the receiver and sure enough. TICK TICK TICK!

Now I was angry. I went back out to the GAP and the walked toward the back corner of my property, another 50 yards or so beyond the gap. VIOLA! I could hear a very faint tick tick tick in the background. I went into my neighbors yard, with permission of course, and proceeded toward the road and the telephone poles. TICK TICK TICK. The noise grew louder. As I walked further down the street under the power lines, the signal became even stronger. TICK TICK TICK POP.

After walking up and down the road, I discovered the noise was strongest near two power poles each of which were in front of a home. TICK TICK POP TICK. The signal was S9 and I was happy. Up upon the power poles were a couple of insulators that looked very old and a transformer that I was sure to be the source of my noise.

I was elated. Now all I had to do was write a letter to the power company, quote a few FCC rules and regulations and ask them to come out and begin replacing equipment until the problem was solved.

Before I wrote the letter, I decided to first review the ARRL website on electrical interference and hopefully find some advice about how to best word the letter in order to obtain the best response. Sure enough, the ARRL had a an entire section devoted to resolving interference problems including a section on dealing with power line interference and the utility company.

I eagerly read all of the information. I was amazed. I had been a ham for 29 years and had resolved several interference problems both caused by my station and caused by other electrical equipment and I was still able to learn much from the information provided on the ARRL website. In fact, it was simply cool that the Internet has enabled us to have quick convenient access to such information in the first place. I read on!

Finally, after reading the entire section on power line interference, it dawned on me that I really hadn't done my homework after all and I was not ready to call or write the local utility to file a complaint. In fact, it is a good thing I had not because I would have certainly wasted their time.

Based upon the information provided by the ARRL I realized that I hadn't really isolated the problem and I could do more before calling in people whom probably had less experience in locating noise interference than have I. The most important thing I had forgotten was to increase the frequency of the receiver as I got closer the source of the interference. I simply isolated it to an area near two utility poles while listening on 28Mhz. According to the ARRL website, I could have isolated it much closer to the source by increasing the frequency of the receiver until the noise disappeared each time I got to the point where the signal was strongest. So, I trekked on.

I continued to increase the frequency, first 50Mhz, then 100Mhz, 150Mhz and 200Mhz, each time getting closer and closer to the source until I was standing in between two homes along the chain link fence that separates them. What now, I thought. Well, first step was to gain the permission of both homeowners to walk around their homes with my handheld receiver in order to figure out from which home the interference was originating.

Fortunately, after introducing myself and explaining why I was there, both homeowners were pleased to permit me access to their yards in order to walk around with my handheld receiver and find the source of the noise. Could you imagine their response if they came outside and saw some stranger walking around with a receiver? These were older people and they may have just called the police.

Nevertheless, I walked around both homes slowly increasing the frequency on the receiver until I narrowed down the signal to the corner of one home, not far from the fence that separated them.

VIOLA! Now I am getting somewhere. I proceeded to knock on the door of the home where the interference was emanating. The older gentlemen was actually outside on his back porch drinking some tea. After his dog alerted him that I was there, he approached and asked if I had any luck finding the signal that was causing my problem. I said "Yes sir, I have. It is coming from your home!" He stared at me with a puzzled look on his face and replied, "Are you sure?". I informed him that I was most certain and I knew it was coming from the back corner of his house, which happened to be his bedroom.

We discussed the matter in some detail and I explained to him how I had purchased this new $10,000 radio and I was very anxious to find and isolate this noise source. I told him it was so important to me that once we discovered which device in his home that was causing the problem, I would happily pay to fix or replace the device. After all, it isn't bothering my neighbor, is it?

He agreed and let me into his home. I walked around a bit with the receiver in my hand and the gentlemen following me. TICK TICK TICK. The sound grew louder as we approached the back of the house. He began to explain to me all the devices he had plugged in. I explained the fastest way to isolate the problem was to start unplugging them until we discovered which one was making the noise. He agreed and began unplugging devices as quickly as he could. TICK TICK TICK, the noise persisted.

First the computer was shut down, then the printer and the fax, then the paper shredder, the clocks and so on. We unplugged everything in his office to no avail and then proceeded to the bedroom. On the way, in the hall, the sound grew TICK TICK TICK. Maybe it is the attic fan I saw from outside the house. It was on the end of the house just above the bedroom window. Up to the attic I proceeded, hot as can be, I made my way to the back of the attic and unplugged the fan. TICK TICK TICK! I was growing weary.

We then proceeded into the bedroom and began unplugging devices, one at a time, the clock radio, the fan, the phone and answering machine. As we unplugged each device and plugged it back in, the noise persisted. TICK TICK TICK. I asked him, "Did you unplug everything?" "Yes", he replied. I asked him to unplug the entire power strip from the wall.

VOILA! The ticking stopped. Unbelievable. A power strip, I thought? How could this be. Nevertheless, plugging the power strip back in restored the noise. TICK TICK TICK. I said, "Wow, that is simple to fix. I have a spare power strip at home. I will be right back". I quickly ran home, obtained a brand new power strip and rushed back to my neighbors house to plug it in.

We plugged in the new power strip and plugged in all the devices. I turned on the receiver. TICK TICK TICK!. Oh no, I thought to myself. This can't be happening.

I finally asked if he would unplug all the devices and plug them into the power strip one at a time. So he did. With just the power strip plugged in, the noise was gone. Then the clock. NOTHING. Then the phone. NOTHING. Then the answering machine. NOTHING. Then an unknown plug. TICK TICK TICK.

"What's that?" I exclaimed abruptly.

He replied, "That's my wife's electric blanket". "Did you unplug it before", I asked. "Yes" he replied, "but there are two plugs, one for each side and I unplugged only one at a time".

We had finally isolated the cause. My neighbor, 300+ yards away is causing severe interference to my receiver with an electric blanket. Wow, after all these months, I finally found the the source of my noise interference.

The man was amazed. In fact, he said he would leave them unplugged until his wife returned and he discussed the matter with her. I offered to buy them a new one, although I could not assure him it would not cause the same problem. He said he hated the thing anyway and proceeded to tell me his theory that all women were reptiles and they couldn't decide if they were too hot or too cool.

Nevertheless, he agreed to leave it unplugged until we found a final resolution. I told him I would check with the ARRL to see if some ferrites or chokes could help or if the blanket needed to be replaced. I would hate to ask someone to throw away their favorite blanket, but I think they may agree if it is necessary.

I wrote an email to the ARRL describing my situation. They responded that it was a known problem and the blanket had been recalled by the manufacturer. I believe they said it was a fire hazard. The ARRL even sent me a link to a page that had audio recordings of the noise. Amazingly, the sounds were identical. The web pages is at http://ve3hls.tripod.com/noise/rfihome.html

David ~ KY1V

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