My DCC layout is 24' by approx 8' at its widest. Large Oval with a large portion that has two tracks and a long 4 track yard. I'm using 12 guage stranded wire. Is it necessary to twist the wire? Just wondering if I didn't (alot easier) would I notice any significant voltage drops that would affect locomotive performance or decoders? Thanks in advance.
The two rails your electrical system feeds are only separated by a fraction of an inch, but that configuration doesn't seem to encourage interference of the DCC signal. My feeling is that the bus should be helical when its length exceeds about 25 feet. Is yours going in one direction only, or is it T'd and issues bidirectionally? If it splits in a T and goes less than 20 feet in either direction, which I think is how most of us do it, you needn't worry about winding the two wires around each other.
-Crandell
selector The two rails your electrical systems feeds are only separated by a fraction of an inch, but that configuration doesn't seem to encourage interference of the DCC signal. My feeling is that the bus should be helical when its length exceeds about 25 feet. Is yours going in one direction only, or is it T'd and issues bidirectionally? If it splits in a T and goes less than 20 feet in either direction, which I think is how most of us do it, you needn't worry about winding the two wires around each other. -Crandell
The two rails your electrical systems feeds are only separated by a fraction of an inch, but that configuration doesn't seem to encourage interference of the DCC signal. My feeling is that the bus should be helical when its length exceeds about 25 feet. Is yours going in one direction only, or is it T'd and issues bidirectionally? If it splits in a T and goes less than 20 feet in either direction, which I think is how most of us do it, you needn't worry about winding the two wires around each other.
LION knows all about twisted pears...
In data transmission the twisted pair is necessary to reduce crosstalk between the wires.
Cat-5e cables are twisted more tightly than Cat-5 cables and as such can carry more throughput on the same wire.
Cat-6 cables are even more tightly twisted (turns per inch) and can carry data in the Gigabyte range.
Network wire is rated to carry this data over a 300' run. You do not *have* 300 feet, nor are you transmitting gigabytes of data. The slowest data transmission is more than fast enough for your application.
The physical separation of the two bus wires also reduces crosstalk, so unless the mfgr of your equimpent specs othewise, do not sweat it.
LIONS run trains on PURE REGULATED DC.
ROAR
The Route of the Broadway Lion The Largest Subway Layout in North Dakota.
Here there be cats. LIONS with CAMERAS
Concur with LION's post. I would be more concerned about induced noise from any nearby (< 12") 110v wiring. As a general rule, I would suggest that DCC wiring cross any 60Hz wiring at a 90 degree angle and as far apart as practical.
No, you don't need to twist it, but it won't hurt anything if you do.
A quick way to twist two wires is to use an electric drill. Twisting it will seriously shorten it.
Dave
Lackawanna Route of the Phoebe Snow
The bus wires on our large (20 x 40 foot) HO scale club layout are stranded 16 gauge speaker wire that is not twisted, and we have never had a problem with the NCE PowerPro system that we are using. The longest bus run from any single booster is probably in the range of 20 feet.
I have over 160 feet of bus wire and it is not twisted. The experts on the Wiring for DCC forum sometimes encourage twisting the bus wires but even they concede that it is not absolutely necessary.
My bus wire is 14 gauge solid copper. Untwisted and I have never experienced a performance problem.
Rich
Alton Junction
I don't twist my bus wires, either. I have them separated by about 2 inches. This arrangement makes it much easier to connect feeders.
It takes an iron man to play with a toy iron horse.
the track is part of the bus. It's not twisted
greg - Philadelphia & Reading / Reading
gregc the track is part of the bus. It's not twisted
I alluded to that contradiction myself in my first sentence above. Two rails, sometimes running unbroken for many yards, only roughly 7/8" apart, and they never, ever, wrap around each other. Not intentionally, leastaways.
While this Urban MRR Myth continues and will probably will forever there are reasons to twist the BUS wires!
While we state the track is running parallel rails -
This WILL induce Induction into the system if they are very long (this where the problem lies - how long is long)!
With twisting the BUS wires this WILL cause a capacitive action (again in LONG wires)
Both of the above problems INDUCTION & Capacitence CAN cause problems in Model Railroads BUS lines.
With having BOTH the Paralled Wire (RAILS) and the BUS under the layout TWISTED - Tends to Cancel the problems caused by having 2 sets of parallel wires! Some EEs will argue this!
99% of the Layout owners will never run into this problem!
BUT - there is 1% that will !
I am one of those!
My layout LOCONET went down last week during an OPs Session and even plugging into the Layout had ZERO effect in controlling the engines!
The problem was NOISE building up on the BUS lines and finally overroad the DCC signal and the Decoders could not decypher the signal from the noise on the BUS wires!
SO no engines would respond!
I did a Cold Reboot to the system and the layout came back up and the Session continued without incident!
WHY did the Loconet go down?
Well it wasn't actually the Loconet but noise building up on the BUS lines!
I had this problem back in 2004 when we would run 12 hour OPs Sessions ans would find after about 8 hours the Operators experienced random loss of control with their engines.
Everyone was using Radios and I suggested they plug into the layout to get through this problem spot!
BUT when they did they still had NO CONTROL of the engines!
I had the BUS lines all twisted from the start and figured I had stopped the problem from ever becomming a problem!
BUT - this was not the case!
I placed a number of Snubbers on the ends of my longest BUS runs and this took care of the problem
But over the years I have been adding more track and longer and longer BUS runs.
The problem came back with a vengence this time!
I have added 6 more Snubbers to the layout to help get rid of the high frequency noise on the BUS lines and will be testing the layout in the coming months!
As I stated 99% will never have a problems but when you have 23 Operators running on the layout - it is a sure fire way to find a problem!
So until you all get up that type of Operations - it is doubtful you will ever experience the problems of noise ont eh BUS lines!
BOB H - Clarion, PA
cmrproducts I have added 6 more Snubbers to the layout to help get rid of the high frequency noise on the BUS lines and will be testing the layout in the coming months!
Bob, where along the layout did you place those snubbers and how did you decide on the location of each snubber?
I just placed them at the ends of my long BUS runs!
The Layout is multi-level and have numerious Blocks
Each Block at the far end - I placed a 2 position termianl strip as a way of making sure that the #!2 Bus wire would never be able to short the ends and screwed the termianl strip to the layout woorwork.
It was easy to put the Snubbers on the end of the BUS run at the terminal strip.
I built the Snubber on a piece of perf board and used scrap pieces of #14 solid wire bent into the holes in the board to hold the wires and then just crimped the Spade Termianls to the #14 wire and also soldered the ends.
I then soldered the .01 Cap and 100 ohm 1w resistor in series with the ends!
I can easily add or remove the Snubber if I choose to and move it etc.
EisenMy DCC layout is 24' by approx 8' at its widest. Large Oval with a large portion that has two tracks and a long 4 track yard. I'm using 12 guage stranded wire. Is it necessary to twist the wire? Just wondering if I didn't (alot easier) would I notice any significant voltage drops that would affect locomotive performance or decoders?
.
cmrproducts Rich I just placed them at the ends of my long BUS runs! The Layout is multi-level and have numerious Blocks Each Block at the far end - I placed a 2 position termianl strip as a way of making sure that the #!2 Bus wire would never be able to short the ends and screwed the termianl strip to the layout woorwork. It was easy to put the Snubbers on the end of the BUS run at the terminal strip. I built the Snubber on a piece of perf board and used scrap pieces of #14 solid wire bent into the holes in the board to hold the wires and then just crimped the Spade Termianls to the #14 wire and also soldered the ends. I then soldered the .01 Cap and 100 ohm 1w resistor in series with the ends! I can easily add or remove the Snubber if I choose to and move it etc. BOB H - Clarion, PA
Thank, Bob.
One more question , if I may.
Do your bus wires radiate out from the command station?
I have 1 - 8 amp Command Station and 4 - 8amp Boosters
All of the Power goes through the PM42 Power managers that Digitrax has.
2 Boosters are located on one side of the basement half way down the long wall
and the Command Station and the 2 other Boosters are on the opposite wall.
I have each level separated into 4 blocks and the BUS wires radiate out from those 2 major locations.
Back in 2004 I was still able to run the whole layout with just the 8 amp command station and we would have 30 Operators running.
When someone derailed the whole layout would shut down and the poor guy that ran the switch has harrassed for doing so!
So my Operators were getting better at NOT running the switches!
But once I began putting the Sound engines on the layout I had to keep adding more and more power!
At this time it is OK but I still run into situations where too many Sound engines are all sitting in the same area and the layout will not come up due to the inrush current!
SO I keep dividing down the blocks so this is not a problem!
I almost have it now figured out!
The wierd thing is this creeping in over time. Unless people are movign wires around, or at the start of the session everyone's train is all at one end of the layotu and later on they are all at the opposite end, the electrical characteristics shouldn;t change that much over an oeprating session. The only other thing would be heat buildup int he boosters changing the operating characteristics of the output transistors. Digitrax has always been the one that doesn't seem to need snubbers most of the time - in part I think this is due to the design of their booster output drive - yes, 'ringing' ona long bus can be controlled somewhat fromt he source end, not just with snubbing circuitry on the far end. So I'm going to guess that as teh transistors heat up, they shift just enough that ringing becomes an issue, and the extra snubbers all is good again. Also explains why anyone not runnign anywhere near the capacity of their system has no problems without the snubbers. ANd maybe why problems crept in as more of the layotu was completed and open to operations.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
(deleted - posted to wrong thread in error)