Does the power bus (track bus) have to be terminated in some way, or should the bus wires just come to an end? If I run my power bus with two parallel wires that follow the track plan, and the command station is attached at the center of the bus, am I OK?
SHould be fine, I never had to do anything, and our much larger club modular layotu never does anything either. Just attach the last feeder to the ends of the bus, or otherwise secure it to the benchwork in a way the ends can;t touch and short out the whole thing.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Thanks Randy. I wasn't sure and teh books I ahve read never mention it.
Some systems recommend termination on very long runs.
I only know this from reading older posts here.
The consensus seems to be that most of the time termination is unnecessary. (But it can't hurt, simple snubbing capacitor and resistor, I believe).
The mind is like a parachute. It works better when it's open. www.stremy.net
Next question: I have seen a set-up in DC using a diode to prevent a loco from going into a blind end on a staging track. The diode is placed between two side of a gap in the rail. The loco drives into the track, but cannot continue past the gap. However it can reverse and back out of the dead end track. How can this be accomplished in DCC?
How is this accomplished? Can you provide an example? (simple snubbing capacitor and resistor,)
RicZ Next question: I have seen a set-up in DC using a diode to prevent a loco from going into a blind end on a staging track. The diode is placed between two side of a gap in the rail. The loco drives into the track, but cannot continue past the gap. However it can reverse and back out of the dead end track. How can this be accomplished in DCC?
Can;t do that easily, DCC is an AC signal so a diode won't block it, nor can you block it one way but not another.
RicZ How is this accomplished? Can you provide an example? (simple snubbing capacitor and resistor,)
See Allan Gartner's Wiring for DCC web site. Unless you have long bus runs (50 feet+) it really isn;t going to be necessary. Only place I ever see people almost ALWAYS using it is with NCE - hmmm.
rrinker Only place I ever see people almost ALWAYS using it is with NCE - hmmm. --Randy
Only place I ever see people almost ALWAYS using it is with NCE - hmmm.
Well, we use NCE at our large HO scale club layout and I use NCE on my home HO layout, and we don't use anything at the ends of our bus runs.
I read the yahoo groups for most of the major systems, and it's always on the NCE one where they talk about adding snubbers. I don't think it's needed, there's enough leeway in the DCC standards that compliant devices should be able to handle a little noise on the line, and if it's THAT bad that your decoders are getting scrambled, I think there's another problem, not an unterminated bus.
Question #1:
I have a Digitrax Super Chief. My bus is about 60 feet long. It is not terminated and works perfectly.
Question #2:
In your blind staging, power that end piece through a momentary contact button. The track will be dead until you push the button. Simply push and hold the button while backing out.
Dave
Lackawanna Route of the Phoebe Snow
Phoebe Vet In your blind staging, power that end piece through a momentary contact button. The track will be dead until you push the button. Simply push and hold the button while backing out.
I use a toggle switch mounted inside a 1 inch PVC water pipe cap instead of a momentary push button. I also mount a green LED as a visual indicator that there is power to the track. Recessing toggle switches inside pipe caps keeps them from being accidentally bumped by visitors.
rrinker I read the yahoo groups for most of the major systems, and it's always on the NCE one where they talk about adding snubbers. I don't think it's needed, there's enough leeway in the DCC standards that compliant devices should be able to handle a little noise on the line, and if it's THAT bad that your decoders are getting scrambled, I think there's another problem, not an unterminated bus. --Randy
I don't follow the yahoo groups for ALL the mfr's, but I do follow the Digitrax and NCE groups and can vouch for what Randy has said.
It seems to come up on the NCE group every couple months or so, and usually starts off with someone saying they're having some issue they can't track down or correct.
But on the Digitrax group it comes up probably only three or four times a year, and as often as not it starts out with someone saying, "On the NCE group..."
Plus, when you consider that the NCE group has only just over half as many members as the Digitrax group, that makes the difference in the topic's frequency stand out even more.
Call me jaded, but I can't picture this discussion ending well.
Crandell