ADSL causes interference on shortwave bands?

P

PeterRbg

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Sedgefield, Southern Cape
This post is not specifically about ADSL/broadband, but about its effect on short-wave communication. I am looking for any input to clarify the cause of this annoying problem.

Briefly, I installed the Telkom ADSL (HomeDSL 192) offering on 11 September 2005. Soon after, I discovered I am getting some consistent interference on the short wave bands ... Not sure if it is caused by the ADSL or not, but for the present I cannot find anything else, unless it is some other broadband / PLC service which started up around the same time.

If you are interested or can throw any light on this, more details are provided at the following URL:

http://www.peterhers.com/ADSL_HF_interference.htm

Thanks in advance for any assistance.
 
Then, if it IS adsl, the transmitting antenna would be the Telkom cable to your building.

Maybe you should try shorting it and seeing if that kills the noise.
 
Final notes on this problem

OK, just to tidy up this thread for anyone interested...

The original problem "appeared" at about the same time my ADSL line was installed, so I was concerned if this was the cause. However, the particular interference I found, approx. every 100 kHz, was traced to a faulty DVD player in the lounge! Of interest is that the interference occurs whether it is switched off or on: The reason is that the power supply is always active, and when you switch it "off" it just puts the equipment into standby mode, but the power supply is still running ... And generating interference! When I pull the power plug out of the wall the interference disappears.

While checking everything else, I found that the ADSL modem does cause some interference as well.
When powered off there is no interference from the ADSL service. Perhaps this is enhanced by in the absence of a signal the "exchange" end stops transmitting and just listens for a signal from the modem.
When the modem is powered on it first goes through a self test. During this phase I cannot pick up any interference, but once this is complete it appears to turn on its output (analogue) signal, and from this point on I can pick it up on HF bands. There is a very definite carrier at 14152, 14213, 14272, 14335 etc.... IE: with a spacing of 61kHz.
This is annoying if I want to listen to a faint signal on these frequencies, but the level is fairly low and the signal is "clean" so it can be notched out. The signal strength does not lift the S meter at all.

I would be interested in hearing about other experiences, particularly those using ADSL services.
 
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