VDSL uses the existing twisted-pair traditional telephone cables to carry high speed broadband data signals between the network provider’s “cabinet” (typically an above ground street-furniture box) and the customers premises.
The frequencies used in the UK are shown below...
The problem however is that the existing telephone cables were only supposed to carry a simple telephone signal in the audio spectrum up to several kHz and not signals of several MHz. As a result, VDSL broadband signals can cause widespread interference as seen in the plot below...
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| VDSL interference to the 7 MHz (40m) & 10 MHz (30m) bands |
The first one on the Mid-Ulster Amateur Radio Club account outlines what VDSL is and ways to deal with interference...
The second one on the Radio Society of Great Britain (RSGB) account describes VDSL and how people in the UK can complain to OFCOM, the UK regulator...
For further reading, RSGB have provided some additional information...
RSGB Frequently Asked Questions about interference
VDSL Interference Reporting
VDSL Interference Advice Leaflet
2 comments:
I believe VDSL can be heard on HF as white noise (ie 'hiss') . Does anyone know what the source of pulse HF interference ,about 15 pulses per second , like the interference from vehicle ignitions of old , is ? It appears from about 3.7 MHz to just below 28Mhz , and is steeply notched out across most of amateur bands . It is apparent 24/7 ,except in power outages .
I notice that near some telephone lines around the country , warbling audio multitones can be heard on longwave radios . Just an observation .
Since we use VDSL2 here in the Netherlands at the main telecom provider (KPN) we as radioamateurs have a lot of problems. Not only suffering more RFI but also causing RFI at individual users. I've had the problem myself and some of my neighbours as far as 500m away did have problems as well. The problem is well known by the TP but since it costs bandwidth to notch out the amateurbands they keep everything quiet. The problem can only be solved by contacting the VERON EMC/EMF committee on a individual basis. 73, Bas
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