[A-DX] Störungen der Mittelwelle

[M. van Arnhem]

-----Oorspronkelijk bericht-----
Van: liste [mailto:] Namens Name gelöscht
Verzonden: zondag 30 oktober 2016 15:15
Aan: A-DX
Onderwerp: [A-DX] Störungen der Mittelwelle


Na, mein Motto ist das nicht mehr! Bei mir hört sich jede, wirlich jede Frequenz so an:
https://www.dropbox.com/s/oks92d9sv5a9nwx/Brumm.mp3?dl=0

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Hello Martin and all,
Don't be surprised about the distance that the interference, caused by a faulty power supply, can travel.
Here is my story.
73

Max van Arnhem
Holland

In march this year I found on my Perseus a strange interference on 1278 khz MW, just about 1 khz wide.
The interference is heard in my local afternoons during a few hours.
I am living in a very quiet surroundings (forestation) with not too many houses in the neighbourhood.
That makes it easier to go out with a portable and to find the house from where the interference is originating.
The house was found about 90 meters from my house.
I paid  a visit to the owner and found out he had lots of devices working in his office, o.a. spots in the ceiling, a huge TV , PC, printer etc.
It was difficult to locate the source of the interference , because it was not at all easy to communicate with the non-technical owner of the house.
A recording of this 1278 khz interference can be heard on :

https://app.box.com/s/mruwe35qbc00e0an550yi86ba61i23e6

Because the interference was audible only several hours in the afternoons on a few days per week and only 1 kHz wide, I left the problem.
However , since a the beginning of July I was suffering from a huge interference , originating from the same house.
This time the interference was noted mostly in the evening between around 1800 and around 2400 LT.
Again I spoke to the owner of the house and I found out that interference is possibly coming from another TV / satellite set in another room.
The  1278 khz interference had gone at that moment; all devices seemed to be switched off in the office.
After he switched on the TV /satellite set in the other room , the interference started.
I made several recordings , which you can hear on this link:

https://app.box.com/s/yjo4i0ww311f36yg5f2yrn74key3nik1

I also noted the interference several times all night.
As said, the owner is non-technical and he said that the installer of this TV/satellite set made the remote control in such a way that with one button he switches on and off his TV and  satellite receiver.
I wonder if this goes well, which could explain the ongoing interference during the night on several occasions.
The owner told me that the last 1-2 years nothing had changed in his TV/satellite set-up, so it seems the interference had suddenly started in an already 1-2 years existing situation.
In September I paid a visit (together with the installer) to the owner of the house from where the interference originated.
After unplugging the power supply of the satellite receiver, the interference disappeared.
We placed the power supply back and found the first minutes no interference; however after a few minutes the interference re-appeared and got stronger and stronger.
By replacing the faulty power supply with a regulated power supply, the problem was solved and the QRM stayed away

This was my 4th considerable QRM in 10 years.
1.  An electric fence of a neighbour very near to my antenna; many clicks and cracks were audible. I contacted the neighbour and he was so nice to dismantle the fence.
2.  A frequency meter of a water pump about 300 meters from my house; MW was completely destroyed. The owner contacted the installer who implemented several filters after which the QRM had gone
3.  A boy welding on old cars about 100 meters from here, last winter on mornings and afternoons resulting in awful interference on MW;  I contacted the boy and asked him to take into account my listening hours, especially in the winter afternoons.
4. The described faulty power supply which was replaced by a regulated power supply.
 
So, being a DXer, life is full of unexpected threats, but sometimes there are solutions, all depending on the kindness of the owner of the device….





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