[ChrisE]

QUOTE (Makemineadouble @ 22 Jan 2006, 19:17)My only comment is that using a telephone in the railway room was impossible with the layout powered up. There was zero interferance outside the room, and zero interferance with the TV's.

<{POST_SNAPBACK}>

Interesting comment as Lenz use a wireless telephone handset & base station as their remote.

Chris

 

[Makemineadouble]

Cell phone & cordless.
hope that clarifys things

 

[Branchliner]

There was I happily constructing my track in the loft today when I suddenly realized that it will make several circuits around the indoor ariels, oops.

I wonder what effect my operations will have on her indoors favourite cookery programs, might help with the steaming.

Brian

 

[ChrisE]

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!

Chris

 

[LisaP4]

My old 0 gauge layout actually ran about 4" above the TV, indoor areial and all! I never had problems with it, although a nearby point motor (tortoise) would occassionally fuzz it up a bit..

 

[dwb]

The possibility of an electric model railway interfering with a TV signal is very real.

The rapid connection and disconnection of an electrical circuit will generate a radio signal. The frequency depends on the rate of closure. The signal can be amplified by an aerial such as a couple of parallel wires - aka the track. For rapid connect / disconnect, ie motor brushes on the commutator or a bad contact through dirty wheels / track.

High frequency signals attenuate more quickly, do distance from the source (the railway) to the affected device - in this case TV aerial may become an issue if they are in close proximity.

The technology for preventing Radio Frequency Interface has come along way since I was "banned" from running trains in the 60s/70s because my dad couldn't see the TV through the "snow", but that doesn't mean that in unusual circumstances there won't be problems. For example it is impossible to listen to Radio 4 long wave in our house if there is a PC on in the next room - and all PCs have to meet RFI emission standards - it just doesn't work too well for long wave.

David

 

[Makemineadouble]

But I've never had a problem with TV interference and DCC.

 

[ChrisE]

Please please please please lets not start discussing the capacitor/ no capacitor issue!!!!!

Chris

 

[SPROGman]

QUOTE (ChrisE @ 21 Jan 2006, 16:36)Sounds like a good idea. I know the way that you mean it is quite safe but can I just stress for the less electrically literate readers that this must be a dry battery - the sort you throw away when they run flat, Ever Ready, Panasonic, Duracell etc. If you use nicads, NiMh LiPolys or lead acid types the results could be burnt out wiring, fire or explosive - literally!!!!

Chris
<{POST_SNAPBACK}>

Eh?

There's a buzzer in the circuit so there isn't a "short circuit" as such, just a battery driving a buzzer through the "shorted" track wiring.

Andrew

 

[SPROGman]

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!

Chris
<{POST_SNAPBACK}>

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.

Andrew