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How Far Does a DCC Signal Transmit?
Phil sent in these questions for readers:
- How far does a digital signal transmit?
- Are their decoders for track switching?
- How does a DCC Loco get its DC power, onboard or does it require an extra car to carry batteries?
- What are, if any, the benefits with a dual power layout, power to track and power from loco?
Dan also sent in this comment which I guess leads to a question:
“I am very interested in converting from DC to DCC. I hesitate only because of potential wiring issues and/or not being able to run my DC equipment.”
3 Responses to How Far Does a DCC Signal Transmit?
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Bachman ez dcc will allow you to run DC and dcc engines
• How far does a digital signal transmit?
The DCC signal is transmitted along the tracks to the decoder in the locomotive. Even in a wireless system, the Throttle transmits the wireless signal to a base that is connected to rails by wires. There is no wireless connection between the Throttle and locomotive, at least I know.
• Are Their decoders for track switching?
Yes there are decoders for deviations and other accessories such as signals.
• How does the DCC Loco get its DC power, onboard or does it require an extra car to carry batteries?
The DC voltage used to control the locomotive and its functions comes through the tracks. The DCC controller sends 14 to 20V to the tracks by square waveform voltage with variable frequency (PWM) and this wave is rectified and filtered within the decoder and used to power the motor, the sound and the other locomotive functions.
• What are, if any, the benefits with a dual power layout, power to track and power from loco?
I did not quite understand that question, but I will try to answer to see if it helps you in some way. No need separate power supplies in a model DCC. The entire power supply is sent by the controller through the rails. What you may need in a very large scale model lay out is the use of Booster who are DCC controllers with more power, feeding isolated track in the model lay out (Power Districts), controlled by a central controller. These Boosters are given the command of the central controller and relay to the rails attached to them with more greater power. When I talk about power, not to say that the tension is higher. The supply voltage rails is the same (14 to 20V), but these boosters has the ability to provide more current (8A) of a basic controller (1.6A).
” I am very interested in the DC conversion DCC . I hesitate only because of possible wiring problems and / or not being able to run my DC equipment . ”
At first, the wiring in a DCC system is simpler than in a DC system, but with the use of more components such as decoders accessories that may be more complex. This will depend on the complexity of your lay out .
How to use your DC models , they will have to be converted to DCC system, but after such conversion , with more modern decoders they can be operated in both systems, DCC is either DC . Unconverted models will not work in DCC system.
I hope I have been able to help.
Best Regards
J.Oscar – from Brasil
Hi Phil, The same thing applies as I stated on the question above you about the expense of switching to DCC. It is basically simple to change over. Remove your existing DC transformer and connect the New DCC system to the main feed for your layout. Turn all your tracks on and after you have a DCC engine you are ready to power up and go.
Wiring will not be a problem if it is a small layout. The larger the layout the larger the wiring. If you are just connected in one spot to the rails the farther away you get and the more rail connectors you cross the more power you will loose. DCC systems work best by feeding buss wires under the rails. I use 16 or 14 gauge trailer wire and follow the rails below. I use 22 gauge phone wires to feed drops to the rails above and I connect to the rails every 4 to 8 feet along the rails. If you are just feeding from one connection the power will drop the farther away you get from the power. A long loop track even in DC you will find you loose power on the far side of the loop. If you have a lot of switches power will get lost the more switches you go through. I connect on each side of the switch to keep constant power along the rails.
There is no secondary power to the DCC chip in the engine nor the motor. The signal runs through rails that after they are turned on will have power through your whole rail system. Your throttle controller will send the signal back to the base unit. it in turn sends the signal through the rails. Your engine will have a code to call up that engine usually assigned the engine number. When you tell that number up and tell it what to do you are sending ths signal through the rails and directly to the chip in the engine. The engine will actually have power on it but just to the chip and after you tell it to go forward for instance or speed up the chip will tell the motor to start up or speed up. if you have sound you ask for the bell it will send the signal to the sound on the chip which in turn sends the signal to the speakers on board. Same with lights.
Yes you will need to convert your engines with a DCC chip. Some systems will allow a standard DC engine to run on the DCC system. It works but there is power on the rails all the time and DCC is just a couple volts higher than DC. So if you do do this it is really only a test run and you DO NOT Leave your engine stopped on the track as with power on and the engine stopped the motor can burn up. I have tested my Thomas engine that in DC it only runs fast. There is no slow to it. But under DCC I can run it slow and I can actually see the eyes move from side to side. This is a good way to see if you really want to spend the money to covert the engine to DCC.
Track switch controls are available called stationary decoders. and these do not have motor functions in them. You can switch track switches, make things work on cars such as the flanges on a snow plow, gates open to company switch tracks etc. They work a little different as they will not be on a code like your engines but on another button usually on your throttle. I have not installed any of these yet but they are planned it to install later.
When converting to DCC get it out of your head that you will be adjusting a throttle just as you did to control the speed on old DC IN DC if the throttle is zero you can short the rails and you will not get a short. But in DCC even with your engine is stopped at zero you will short if you jump the rails. So if someone dops a tool across the track it will pop the breaker till the short is removed. The system test is to drop a quarter across the rails and it should short pop the breaker and remove power to the system. If it doesn’t and I have seen this on someone elses layout it can burn something up The system is not good if the breaker does not pop.
There is some out now that the engine runs on battery and radio. I have seen a demonstration of that. Battery limitations is a problem to run very long. If doing this on a powered rail and there is a short in the system it will stop all rail powered engines and will not affect the battery powered engine. There is advantages to both but I would still go with the DCC system. Durty tracks will affect the DCC engines where battery engines will keep going. The more engines on the DCC systems the more you will need to add a booster to the layout for more power. Longer distance from the main power will also need a booster. But without a booster I have had 12 engines running at the same time. I have consisted 3 engines together as a team on 3 trains at the same time. If your layout is small you will most likely never need a booster. It is nice though that if you have a switch yard, and you use a breaker panel something like your house breaker box, if the yard is on one breaker and the main lines on another and there is a short with someone running in the yard it will not affect your trains running on the main lines and vise- versa.
Hope this helps from Newman