[HCDX] Severe rfi
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[HCDX] Severe rfi

Thursday, January 15 2015
  
Hi!
I have a big problem with a special local nois apart from much
Ãnormalà urban rfi. The noise cover nearly the entire shortwave band
except the amateur band. It's obvious that that the device producing
the RFI must have a filter to avoid interfering the amateur band. Its
nearly impossible to hear anything else. I do have a buried beverage
that help me much as the noise on this es more less.I have uploaded a recording on youtube of it. What can it be? I also
wonder if a MFJ-1026 noise canceler will be able to cancel it? Anyone
knows? The noise is very strong! Using a portable radio receiver it
indicates that it comes from a close neighbor.
www.youtube.com/watch?v=HJpSHHjePggThanks !
Levi P. IversenElverum - Norway
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Hi Levi,
Sorry to hear about your interference problem.The source is definitely from a home powerline networking kit. I have been suffering similarinterference from six different sources near my house since 2010. I have managed to getsome of them removed over the years, but then others appear! Of course the amateursare lucky because their frequencies are "notched out". This does not help us who like to 
DX the other short wave frequencies for broadcast and utility stations.As well as this "PLT" interference, I also get noise from from my neighbours' switch mode 
power supplies, low voltage lighting and so on.

There are several things you can do:
1. Approach your neighbours and politely explain the problem you are having. (Not easy -you do not know how they may react). You can use your portable radio to demonstrate to them. 
If you find the culprit and they do not co-operate, you can offer to pay for installation of any alternative 
kit, such as Cat5e cable or Wi-fi if this is available.

2. If you have no success with this, you can contact the Norwegian TelecommunicationsAdministration to see if they can help you.
3. You can use the MFJ-1026 noise canceller My set up here includes a Wellbrook ALA1530 
magnetic loop antenna. This helps a lot with the other sources, but does not completely 
remove the powerline adapter interference. 
I am also using the Wimo noise canceller, which is more compact, is well-made and works 
very well with the Wellbrook and my other antenna, a trap dipole.ÂÂ
Because you are using a Beverage antenna, I am guessing that you have a large piece of 
land behind your house. In that case I suggest you install a dipole antenna on top of a poleas far away from your house and neighbouring houses as is possible. The "inverted V"type, with the arms pointed away from nearby houses is strongly recommended.Use coaxial lead to the receiver. I also have a "preselector" (antenna tuning unit) which isconnected to the Wimo canceller and then to the receiver (Yaesu FRG7700).
The problem is the Wimo can sometimes only remove one interference source at a time.It also needs a second "auxiliary" antenna. (I use 15 metres of wire indoors). This secondantenna has to "hear" the interference as well as the main antenna, so it can be cancelledout. Also, scanning the frequencies is not easy, as the Wimo constantly needs adjustingas you change frequencies because the interference comes back. But without this noise 
canceller, I would definitely have given up my short wave hobby (after 46 years). 

I am hoping that new rules from the regulator Ofcom, will enable UK listeners to enlist 
their help to remove these terrible devices when interference is experienced. 
(The EU should never have allowed this networking kit to be placed on the market - it breaks 
all the existing rules on "EMC" compliance for household electrical appliances). 

That's all I can suggest - of course as a last resort you could move to a remote location instead!
73
Alan Holder(also radio amateur G4ZBH)Isle of Wight, UK


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