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An RFI Problem with a Happy Ending

from Jónas Bjarnason, TF3JB on July 18, 2015
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An RFI Problem with a Happy Ending
By Jónas Bjarnason, TF3JB

One morning in April 2014, annoying reception interference was discovered on the 20 meter band at TF3JB. The interference was “raw and aggressive” not unlike unfiltered AC. Tuning the transceiver over the band, the interference varied between S5 to S9 in strength; often peaking at close to 14.065 MHz and at times fluctuating up to 14.290 MHz. Similar interference was noticed from 10 MHz to 25 MHz, but less in signal strength.

The next weeks it was impossible to work DX on 20 meters at my QTH because the interference was there 24 hours a day. During that time I more or less hoped that the interference would go away; but it did not. By the end of May, my patience had run thin, and an irritated TF3JB borrowed a Sony 7600DS portable receiver. This receiver (battery powered) covers 1.6-30 MHz, has a BFO, an antenna attenuator, and an extractible antenna. The plan was simple, to walk on foot with the receiver in the vicinity of my vertical antenna, in the hope to locate the source of the interference.

As I live in a densely populated residential area in the capital, I was prepared for this to be a time consuming and complicated search. I was thus pleasantly surprised when I was able to locate the probable source relatively soon, radiating from a private residence in a neighboring street. To be on the safe side the procedure was repeated the following day, with identical results.

With no justification to stall things further I went up to the house, rung the bell, and explained who I was and why I was there. To illustrate the problem, I turned on the portable receiver in the doorway and right away I was invited to enter and the owner even appeared enthusiastic to have the problem solved. Once inside, I noticed a control box for a home security system in the hallway and holding the Sony receiver up close, it seemed to give off the interference. In order not to disturb the family more than necessary, the owner was happy that I would contact the security company to request an assessment of the system. I called Securitas and they agreed to send their service technician the next day without cost (apparently because the system had been malfunctioning some months back).

1: The 20 meter band was particularly important for DX work [at that time] since the higher bands were mostly closed in the spring of 2014.

The following day, when the service technician arrived it took him only about half an hour to fully check out the system. Afterwards it was certain that the house alarm system was not to blame. Due to personal time restraints, I could not do more that day.

When I visited the house again I took my father along who is a licensed electrical contractor. The electrical wiring was examined and being a large house, there were several breaker boxes to inspect (but no electrical schematics at hand). Although a relatively new house (built in 1983) changes had been made to the wiring without taking care to label the changes in the breaker boxes. Consequently, it took time to sort things out, but we were finally able to isolate the interference to the 2nd floor. Unfortunately, the family member who lived there was not available at that time. It was thus agreed that we would be back in two days and seek to finish the job.

We returned to the house on the agreed day. With the portable receiver it only took us a few minutes to locate the definite source of the interference. The culprit turned out to be a BYTECC Desktop External Computer Hard Drive with an accompanying switch mode power supply; “Model SP12.0/5.0-2000“. Once the power supply was disconnected, the interference disappeared. In full agreement with the family, I offered to have a talk with the retailer to claim warranty on their behalf, since the hard drive was only a few months old.

Above: The BYTECC desktop external computer hard drive. Below: The accompanying power supply.

A week had now passed, and on a following Monday morning I visited the retailer and explained why I was returning the hard drive. I was asked to come back the next day, since the request would need to be approved within the company. Upon return, I was told that they would favor the warranty. Later that day I picked up a replacement unit when the content of the old drive had been transferred. I was pleased to learn, that the replacement hard drive was of a different brand that was supposed to be of good quality. That evening I returned with the new unit to the family. They were all pleased that the problem was solved. It goes without saying that I was of course thrilled to have the 20 meter band back.

In closing, I must admit that for weeks after the interference was gone the thought grabbed me each time I turned on the transceiver, what if the problem is back? Fortunately that has not been the case. However, if it does the experience gained above will certainly help.

Electromagnetic interference (EMI, also called radio-frequency interference or RFI when in radio frequency) is disturbance that affects an electrical circuit due to either electromagnetic induction or electromagnetic radiation emitted from an external source. The disturbance may interrupt, obstruct, or otherwise degrade or limit the effective performance of the circuit. These effects can range from a simple degradation of data to a total loss of data. The source may be any object, artificial or natural, that carries rapidly changing electrical currents, such as an electrical circuit, the Sun or the Northern Lights. (

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An RFI Problem with a Happy Ending  
by RADIOPATEL on July 18, 2015 Mail this to a friend!
Really very good operation with Ham Radio Spirit.Thanks to your neighbour also.Your enthusiasm needs a Salute.

Dinesh Patel - VU2DCI
An RFI Problem with a Happy Ending  
by KC2WI on July 18, 2015 Mail this to a friend!
You were realy lucky you had a cooperative neighbor.

I spent 3 months trying to resolve a problem of broadband noise from 1-5-7 MHz (S9 on 75M) resolved.

I knew where the RFI was coming from, talked with the neighbor, and suggested a likely cause - either satellite box or modem. They said they would call the company but when I talked with the neighbor a couple weeks later, they said the company said "can't be us."

There is no way they would let me in to track down the problem, it had to be done by haveing the power company, phone company, and cable company people knock on their door. The people just didin't respond to efforts by the cable company to change the modem.

An RFI Problem with a Happy Ending  
by VE3XQQ on July 18, 2015 Mail this to a friend!
Jónas your exemplary spirit of cooperation is what we need more of in Ham Radio.

I have a similar situation that covers the entire HF spectrum at 70KHz intervals. It started in the spring but it comes and goes, so I think it is someone’s grow light. This makes it annoying and yet the hunt is exciting.

As a side note; I am a retired from the Canadian Air Force and in the 70's when on the east coast we used to fly into Reykjavík with the CP 107 Argus, a 4 engine piston long range patrol aircraft.

73 de VE3XQQ, Frank
An RFI Problem with a Happy Ending  
by K1FPV on July 18, 2015 Mail this to a friend!
Congratulations on solving the problem. Unfortunately, many of the small cube type power supplies being built in China and exported to the USA as well as the European Union have this problem.

About 6 months ago, I purchased a video distribution box that used one of these Chinese cubes to power it. Like your situation, it radiated noise over much of the HF spectrum. I was able to obtain a replacement power cube, but unfortunately it too caused hash in the HF spectrum. I wound up building my own small power supply to provide the +12VDC and the situation was rectified.

I'm finding a decent percentage of the electronics coming out of China to either emit noise or being very susceptible to RF interference.

An RFI Problem with a Happy Ending  
by JOHNZ on July 19, 2015 Mail this to a friend!
Spent time at the Keflavik NATO base in the 70s. Iceland is a weird country, and the locals are not very friendly.

When we operated ham radio from the NATO base, we were required to use our American call sign, portable TF. Had something to do with the Icelandic hams not wanting us to have TF call signs. Attended a ham radio club meeting in Reykavik, and the locals really gave us the cold shoulder (no pun intended). Understandably, the meeting was conducted in Icelandic, but despite the fact virtually all Icelandics speak English, not a single Icelandic ham would converse with us in English, before or after the meeting.

Got to know an American who worked on the NATO base and was married to an Icelandic woman and had a home off the NATO base. His call sign was K1NGK, George Hauser, I think. Despite being married to an Icelandic woman, he did not care for the locals. He had a tower at his home and was also required to use his American call sign, portable TF.

I had a small 50 watt transceiver with a dipole on the NATO base and would have nightly QSOs with east coast American hams on 75 meters.

Oh, the locals would feign being friendly, when they wanted us to buy them "wodka" (vodka) at the NATO class six store (no local taxes). It was illegal to do so, and the penalties were very severe, since it was considered smuggling, so we would always refuse them. Suddenly, they were no longer friendly.
RE: An RFI Problem with a Happy Ending  
by HB9MQM on July 19, 2015 Mail this to a friend!
@JOHNZ: May I please ask what your comment about allegedly unfriendly natives in Iceland has got to do with the topic of searching for a RFI source?!
RE: An RFI Problem with a Happy Ending  
by TF3JB on July 19, 2015 Mail this to a friend!
First of all let me thank everybody who has taken the time to comment on my short article. My empathy goes out to those left in such a situation where it is, for one reason or another, not possible to put things right. RFI is no laughing matter.

Although not discussing the article at all, I feel that I need to comment briefly on the text written by “JOHNZ”.

I am very sorry to learn about your unfortunate experience when you were stationed at the NATO Base in Keflavík in the 70s. Our reciprocal agreement with the U.S. came into force in April 1978. In all reciprocal licensing, it is normal that the alien uses his/her call sign slash the prefix of the visited country. It would have been normal that this applied to you as it applied to me when the FCC granted me a reciprocal license when I moved to the States in January 1990. Nowadays, however, with CEPT, this has changed and the prefix of the visited country is now used slash your call sign.

I knew Heinz “George” Stroebel, WA9UZM. He passed away in November 2014. He also had an Icelandic call sign, TF3XG, and was taking steps towards getting QRV again (with help from his Icelandic ham friends) when sadly, he died. His surviving spouse “Lilly” is a licensee.

When I was first licensed in 1974, my ham friends at the base helped me to buy used equipment from a ham that was being transferred. I enjoyed my Drake line for a number of years. Many other Icelandic hams can tell a similar story.

If you would like to discuss this further and send me a private E-mail, my E-mail address is: “”
An RFI Problem with a Happy Ending  
by KC0KEK on July 19, 2015 Mail this to a friend!
From the title, I assumed that the source was in a massage parlor.
An RFI Problem with a Happy Ending  
by JOHNZ on July 19, 2015 Mail this to a friend!

My experience with the call sign issue was prior to the 1978 agreement. American hams had Icelandic call signs prior to the early 70s. The Icelandic call signs were taken away, because local Icelandic hams wanted to keep "TF" as rare DX. I could care less, so it is really a non issue with me, because I operated all I wanted to from the NATO base, using my American call sign portable TF and had virtually daily contact with friends on the U.S. east coast nightly on 75m.

You got ham gear from people on the NATO base? I recall the NATO base gate as being considered an international border. Therefore, I can only guess at what customs forms you had to fill out and what hoops you had to jump through to get that gear through the NATO base gate?
An RFI Problem with a Happy Ending  
by N8CMQ on July 19, 2015 Mail this to a friend!
Noise in NEW electrical equipment is very frustrating.

I installed two new florescent fixtures, and BOTH make noise.

As one of the fixtures is over my workbench, I have to turn it off when trying to check out receivers. I have to turn off BOTH for good noise figure testing...
RE: An RFI Problem with a Happy Ending  
by K9ZMD on July 19, 2015 Mail this to a friend!
Wow, Tim - That was a conversation-stopper.
An RFI Problem with a Happy Ending  
by AB9TX on July 20, 2015 Mail this to a friend!
"Once the power supply was disconnected"

Was it the power supply or the hard drive?

And is that an FCC label on the brick?

RE: An RFI Problem with a Happy Ending  
by VE3YF on July 20, 2015 Mail this to a friend!
Hi Jónas:

Your article is very well done. Congratulations on resolving the interference problem. You took a very professional and courteous approach to the problem and your neighbor probably seen that you were polite and courteous and welcomed you into their house to resolve the problem. I have had a few issues over the years and I also have found that being polite and courteous can go a long way towards resolving the problem and still keeping good relations with the neighbors.

However I have seen a few local amateurs who took the same approach as you did and were not let into the neighbors house. Sometimes the neighbors are not interested in resolving issues and darn outright rude type of people. Wish all amateurs were as lucky as you and I have been. It is amazing that such a small device (External HDD and Power Supply) can be so much problems. Job well done.

73 De Mike
An RFI Problem with a Happy Ending  
by WY4J on July 20, 2015 Mail this to a friend!
Positive resolution to a problem. I noticed that this happened in Iceland, country with nice people. This would not have turned out the same in my town, Miami, Fl. Most likely if you knocked, your neighbor would not answer the door. If you insisted he/she would call the police or open the door show you the business end of a Glock.

In this town most people avoid eye contact as most carry concealed firearms. Florida is proud of being the #1 issuer of concealed firearm permits. There is absolutely no way anyone would let a stranger into their home let alone their upstairs bedroom.
RE: An RFI Problem with a Happy Ending  
by TF3JB on July 20, 2015 Mail this to a friend!

A good observation and thank you for the question. It was discovered at the service center of the importer that it was the switching power supply.

73 de Jónas, TF3JB.
RE: An RFI Problem with a Happy Ending  
by TF3JB on July 20, 2015 Mail this to a friend!

Sorry, I forgot to respond to your second question. Yes, there is both the FCC and EC markings on the switching power supply.
RE: An RFI Problem with a Happy Ending  
by AB9TX on July 20, 2015 Mail this to a friend!
Well- placing "FCC" on an electrical appliance should be a huge liability issue if this device did not get certified. The manufacturer and vendors could be looking at pretty a good fine- one would hope.
RE: An RFI Problem with a Happy Ending  
by K9MHZ on July 21, 2015 Mail this to a friend!
"Well- placing "FCC" on an electrical appliance should be a huge liability issue if this device did not get certified."

Maybe, if you could figure out which Chinese sweatshop did the deed.

RE: An RFI Problem with a Happy Ending  
by K1FPV on July 21, 2015 Mail this to a friend!
AHHHH! That is the big question! Often, I find that these supplies do work, but they are either noisy, or more susceptible to RF causing all kinds of weird stuff!

RE: An RFI Problem with a Happy Ending  
by KA3AUD on July 21, 2015 Mail this to a friend!
I understand Iceland is quite cold.
RE: An RFI Problem with a Happy Ending  
by KC8UEJ on July 21, 2015 Mail this to a friend!
I thought it was about an Asian massage parlor also. How disappointing:)
RE: An RFI Problem with a Happy Ending  
by KN1W on July 21, 2015 Mail this to a friend!
My only thought was regarding any important data on the hard drive bouncing around in someone's car in route to an Icelandic Best Buy. I guess they were backing up to the Cloud.
Great story!
RE: An RFI Problem with a Happy Ending  
by ON5MF on July 22, 2015 Mail this to a friend!
"Well- placing "FCC" on an electrical appliance should be a huge liability issue if this device did not get certified."

In Europe we all know that 'CE' usually means China Export...
An RFI Problem with a Happy Ending  
by JOHNZ on July 22, 2015 Mail this to a friend!
Based on my time at the Keflavik NATO base, I recall temps reaching 60 deg F during June & July, during which time Icelandic women would don bikinis and sun themselves in their backyards. Winter temps would not dip lower than 10 deg F, because we were told that warm ocean currents kept the air warm, at least in the Keflavik area. However, the wind never stopped blowing, and winter "white outs" were common.

Driving on a rough road is common, since the only paved main highway was between Keflavik and Reykavik, which was a toll road, circa 1970s. Iceland has a socialist government, which is unfriendly toward big corporations like Best Buy. Due to socialism, their economy went broke and collapsed a few years ago. Today, I think, they are heavily dependent on foreign tourist dollars. It is a classic "nanny state," to the point where they banned people from owning dogs and ordered TV stations off the air during summer months in order to force children to read books during their summer vacation. The TV ban resulted in Icelandics constructing huge VHF antenna arrays to receive the low-powered TV transmitter located on the NATO base, which featured American TV shows.
An RFI Problem with a Happy Ending  
by VA3PUX on July 27, 2015 Mail this to a friend!
A few months ago I had a like experience with my direct neighbour. The original power supply for their Asus laptop failed and was replaced with a "Made in China" POS. It radiated all over 20 meters making it unusable. Through some encouragment I was able to visit their home with a portable radio to locate the source. Upon discussing it with them I purchased an original Asus replacement supply. All is good since then.
RE: An RFI Problem with a Happy Ending  
by TF3JB on July 28, 2015 Mail this to a friend!
Congratulations. This is not easy but the good thing is to get rid of the problem.
RE: An RFI Problem with a Happy Ending  
by VR2AX on August 2, 2015 Mail this to a friend!
Coincidentally, my XYL and I spent nearly a week in and around Reykjavik, in June 2015. I would fully endorse the positive comments above, regarding the friendliness and co-operativeness of the local people we encountered there. A local postal lady took a few minutes out of her schedule delivering letters to point us in the correct direction.

The only "RFI" we encountered was from foreign visitors, generally young American and Europeans, who were intent on handling out leaflets on the street (mostly, regarding the whale trade).

Adding an Eastern/Asian perspective, based on 30 years experience, the typical reaction in Hong Kong, Macau and China, would be to completely ignore you at first, and if a face to face ever materialized, deny, deny, deny.

Well done.


An RFI Problem with a Happy Ending  
by JOHNZ on August 6, 2015 Mail this to a friend!

Sure the Icelandics were friendly and cooperative. They are in desperate need of foreign tourist dollars, since their socialist economy collapsed a few years ago, similar to what is going on in Greece now. A tourist in a foreign country for one week cannot possibly form an accurate opinion of the "real" locals. Your contact was mainly, if not entirely, with those who cater to foreign tourists. Their livelihood depends entirely on being nice to you. NATO personnel were stationed in Iceland for six months to a year. NATO personnel were not tourists and were not there by choice. That 12 month time period gave NATO personnel a whole different perspective on Iceland than that of a one week tourist.

In all fairness, the same can be said for other places, such as Hawaii. Tourists always return home all giddy about Hawaii. Try living there for two or three years, and you will find out the locals do not like people from the mainland or foreigners from other countries. However, if you are a tourist, they love your money.
RE: An RFI Problem with a Happy Ending  
by VR2AX on August 10, 2015 Mail this to a friend!
Good rejoinder. Your 1 week vs 1 year point is a whoosh Mayweather v Pacman point to answer.

There are no absolutes: the Postwoman was not after my dollars; the '70s Icelanders were after yours.

Ever do Greece in the 50s? I did. Brits were not too popular. Socialist or one primary against another, isn't it nice a potential dispute never became the real thing. It's not what who you are but often what you stand for that makes the diff.

Take care.
An RFI Problem with a Happy Ending  
by KB0RDL on August 15, 2015 Mail this to a friend!
I had a similar problem many years ago. I took my portable shortwave radio around and located the RFI problem quickly -- it was right next door. I visited the family living there -- it was a rental -- and they let me in with my radio to see what it might be. It was the furnace fan. They told the landlord and he replaced the motor within the week.

Now I have a magnetic loop antenna and it eliminates most of the RFI, plus it has a strong null in two directions if you need to use it.
An RFI Problem with a Happy Ending  
by KC9NCS on August 22, 2015 Mail this to a friend!
This is one heck of a coincidence. I had the exact same problem about a year ago now with the exact same USB HDD Case and Wall Wart with one significant difference:

It was in my shack.

In my case, anything above 40m was non-stop electical noise varying from a steady S5 on 40m, 20/9 on 20m and anything above 20m was completely useless.

In my case, I used an old AM/FM shower radio that I use on a daily basis --- ironically while taking a shower but I digress.

I was initially convinced the noise was coming from outside my home, and expected the problem to be in the ComED box in the easement as ComEd had been doing work in my area before the problem occurred.

I took my trusty shower radio, tuned it to AM 1600 where I could hear the noise and walked outside the house towards the ComEd box. Funny thing, the further I walked away from my house, the less the noise was. So I decided to walk around the house. As soon as I reached the EAST side of my home, I heard the noise. I confirmed the noise being on the east side by walking around my house several times listening to the noise disappearing as I walked towards the South, then West, and North sides, with the noise returning on the EAST side.

Having purchased new kitchen appliances (refrigerator, dishwasher, garbage disposal, range, microwave...) I was convinced one of them was the culprit as my kitchen is on the east side. I left the radio in the kitchen and went to the basement to switch off the kitchen breakers. Returning to a dark kitchen as it was in the evening, my trusty shower radio sat there on the countertop still receiving the noise.

Taking my trusty shower radio in hand, I proceeded to walk around the rooms on the EAST side of my home. I noticed that when I walked by an electrical outlet the noise was exceptionally loud. I concluded whatever was causing the noise was something connected inside my home (well duh!) It didn't matter which room in the house I walked in, anytime I got near an electrical outlet the noise was exponentially worse.

That's it, I thought to myself. Leaving my trusty shower radio in my family room, I turned it up full volume and went back down to the basement to start shutting power off to rooms one by one until every room except my shack were turned off at the circuit breaker.

I went back upstairs and picked up my trusty shower radio in complete disbelief. Was it lying to me? Where is this noise anyway?

I went back outside and walked around the house with my trusty shower radio. Every time I walked around the house and got to the EAST side the horrible interference noise was heard.

Then it struck me: my shack is on the EAST side of the house. DOH!!!

Back inside the the shack, I started looking around at everything I had connected. Lo and behold, I had four devices with those ugly wall warts or power bricks and I began unplugging. As soon as I unplugged the power brick for the ByTecc USB HDD enclosure the noise DISAPPEARED. The culprit was found.

When I unplugged it, I noticed that the power brick was beyond "warm" and was actually quite hot to the touch.

I suspect that had that power brick been left plugged in much longer, I might have had an electrical fire or the power brick could've caught fire itself and ignited something else around it.

To me, this wasn't just an exercise in patience in finding a noise source, it turned out to be a valuable lesson: external power sources such as wall warts and power bricks should routinely be checked for safety. I now make it a practice to visually and physically check all external power sources (wall warts, power bricks) and power strips on a monthly basis. If something feels too warm, it gets replaced and there are NO exceptions in my house.

As it turns out a year later, it's a darn good thing I do check every month.

Youngest son has a very large aquarium in his bedroom and recently purchased a set of LED lights for his plants and fish. The LED lights came with the ever popular power brick. He setup the lights on his tank and plugged in the power brick.

About a week later, I started hearing interference on 20m and above. On 20m it was S9. My son's room is literally right underneath my inverted V.

When I started hunting around the house for yet another wall wart or power brick run amok, I asked to see how he connected his LED lights up. Sure enough, it was a power brick that he plugged in and kept underneath his bed to hide the wires from the lights. I reached under his bed to remove the power brick and damn' near burned myself on it. I reached to where it was plugged in and yanked the hot cord out of the wall, and removed the power brick from under his bed.

Holding the power brick by the cord, I told my son to take the power brick from me so he could see how hot it was. I explained to him that under no circumstances was he to ever plug in a wall wart or power brick without my checking and inspecting it first, nor was he to "hide" them behind other things such as furniture.

I'm firmly convinced that my experience with my own ByTecc USB HDD power source a year earlier, and my practice of routinely inspecting any and all external power sources (wall warts, power bricks) on a regular basis in my home may have prevented a fire, or worse in this specific case.

As a result, I would urge all Ham's to adopt the practice of routinely inspecting any external power sources in their homes on a regular basis and removing/eliminating any they find that are hot/too warm to the touch.

While this is quite hard to do these days, my own practice is to whenever and where ever possible to AVOID purchasing devices with external power sources specifically because of these types of issues. Again, whenever and where ever possible.

One last comment: In the case of the power bricks for my ByTecc USB HDD enclosure and my son's LED lights, both were made in .... you guessed it: CHINA.

Without getting into a political diatribe about cheap Chinese labor and the destruction its caused to American jobs and manufacturing, the truth is the quality and safety of products coming from China is woefully substandard. I can now point to two cases in my own home where left unchecked Chinese manufactured devices posed a direct safety threat to my home and my family. Whenever and where ever possible, I avoid products made in China specifically because I deem anything made there to be unsafe. YMMV.
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