QUOTE (ChrisE @ 23 Jan 2006, 22:04)I assume you are jesting about the TV but I really still don't see the problem here. Your house is full of wires carrying 240v ac which will do much more than the 16v ac that a model railway BUS runs at.
Any piece of electrical equipment sold in the UK, as I understand it, has to be CE compliant & one of the tests this includes is introducing radio interference. That covers your DCC boxes.
On this basis I cannot see that a model railway should interfere with telephones any more than the mains cables in the wall of your model room & I would be very surprised if it caused interference with anybody's TV unless you have a very marginal signal.
It would be a major failing if DCC could not be used near telephones or TV aerials!
Three main differences are:
1. Frequency. Mains is only 50Hz and can indeed cause interference. have you never heard the term "mains hum"? Ask anyone serious about HiFi.
2. The mains is nominally a sine wave. The DCC signal is a square wave and will have more energy in the harmonics (frequency multiples) of the main signal.
3. Every track-wheel and wheel-pickup interface will generate high frequency interference due to arcing just as a the motor brushes do on the commutator on a DC loco. These are suppressed by capacitors across the motor which aren't generally required in a DCC loco due to the design of the decoder. The decoder does not suppress interference from the wheels.
EMC testing of DCC boosters cannot possibly be carried out for every possible track topology. The track is basically an antenna radiating the DCC signal and every layout will be different.
The reverse is also true, all electrical equipment has to pass tests for immunity to interference. So, even if your DCC is noisy, the TV, radio, phone, etc should be reasonably immune if it's a modern one and you don't happen to generate intereference at its intended operating frequency.
I've heard anecdotal evidence of people being investigated for causing interference with the result that the complainant was told to buy a better TV aerial.