Put on a small extension and need to extend my track bus 4-5ft and was wondering if I could just use a suit case unit to extend it or a solder joint or another means is ok. Just going from a total track bus length of 15 ft to 19 or so ft with 14 gauge wire N gauge. Thanks much
If it were me (and I am serious), I would wrap the two ends generously and use a Marrett. If the joint will be out of the way and protected, why not just use what household electricians have done for donkeys' years?
KISS
Yep. Not a problem.
The only thing that you want to watch out for is that you don't make the DCC track bus an oval or circle that connects back on itself. That goes for the track too. If your mainline is an oval, there should be a double gap near the same place that the DCC buss ends, in both directions.
Elmer.
The above is my opinion, from an active and experienced Model Railroader in N scale and HO since 1961.
(Modeling Freelance, Eastern US, HO scale, in 1962, with NCE DCC for locomotive control and a stand alone LocoNet for block detection and signals.) http://waynes-trains.com/ at home, and N scale at the Club.
gandydancer19 If your mainline is an oval, there should be a double gap near the same place that the DCC buss ends, in both directions.
If your mainline is an oval, there should be a double gap near the same place that the DCC buss ends, in both directions.
I'm curious as to the reasoning of the above and was hoping you could explain why that's necessary.
I have an oval for my main and I did not do this as none of the books ever mentioned it. Everything seems to be working fine for me.
Again, just curious.
Thanks
opaque333 gandydancer19 If your mainline is an oval, there should be a double gap near the same place that the DCC buss ends, in both directions. I'm curious as to the reasoning of the above and was hoping you could explain why that's necessary. I have an oval for my main and I did not do this as none of the books ever mentioned it. Everything seems to be working fine for me. Again, just curious. Thanks
Old wive's tale.
As your own layout proves, there is absolutely no reason why you can't have your track bus in a loop.
The throttle/command bus is a different story. It should never be looped back to itself (which is probably where the track bus misinformation comes from...)
scott018wondering if I could just use a suit case unit to extend it or a solder joint or another means is ok.
The suitcase would be the last type I would choose. Use a wire nut, solder joint or a crimp type butt connector.
Jim
Somewhat related ... how do you terminate the end of the track bus if it isn't a loop. Are there any issues with it ending at a barrier strip?
kelleywpns Somewhat related ... how do you terminate the end of the track bus if it isn't a loop. Are there any issues with it ending at a barrier strip?
No, that would be fine.
Only the added expense, unless you happen to have an unused barrier strip handy. I only leave my bus ends held firmly by an electrical staple. I don't even cover the ends. It the ends are up against the nether surface of the layout's base, say a sheet of plywood, they only need to be kept from dangling and gouging the careless and unbending back.
Stevert opaque333 gandydancer19 If your mainline is an oval, there should be a double gap near the same place that the DCC buss ends, in both directions. I'm curious as to the reasoning of the above and was hoping you could explain why that's necessary. I have an oval for my main and I did not do this as none of the books ever mentioned it. Everything seems to be working fine for me. Again, just curious. Thanks Old wive's tale. As your own layout proves, there is absolutely no reason why you can't have your track bus in a loop.
Whether your track bus can have a loop, or an unterminated end depends on the length.
Roughly speaking (we're talking crayon on toilet paper, not 0.5mm 2H pencil on quad-rule!):
The standard allows for a ~3 microsecond transition time in the +/- 4V region around the zero crossing. This means that the track bus should not have any significant reflections that occur after ~1.5 microseconds. Assuming a propagation speed of 11 nanoseconds per foot in the wiring, that means you are limited to a bus length of 137 feet round trip (out and back), or 69 feet one way before you might need electrical termination (e.g. snubber) on the end. Also, If your bus length to the nearest part of the loop, plus the loop perimeter, is less than 137', you need not worry about whether it is connected in a loop electrically. If the loop is longer than that, then break it (and double gap the track) at a point roughly opposite the booster, and terminate (snub) both ends.
Andy
Looping a bus has never really been a problem. That's because by the time a looped bus is long enough to cause problems, it is also long enough that another booster district is needed. There must be a gap in the rails and the wires between booster districts.
Martin Myers
Stevert opaque333 gandydancer19 If your mainline is an oval, there should be a double gap near the same place that the DCC buss ends, in both directions. I'm curious as to the reasoning of the above and was hoping you could explain why that's necessary. I have an oval for my main and I did not do this as none of the books ever mentioned it. Everything seems to be working fine for me. Again, just curious. Thanks Old wive's tale. As your own layout proves, there is absolutely no reason why you can't have your track bus in a loop. The throttle/command bus is a different story. It should never be looped back to itself (which is probably where the track bus misinformation comes from...)
Brent
"All of the world's problems are the result of the difference between how we think and how the world works."
gandydancer19I suggest that you READ through your COMPLETE DCC MANUAL and follow it's instructions. My NCE manual says that the DCC bus and track should not form an electrically closed loop. Maybe your DCC system is different, but I know us NCE users never have any problems by not making the track loop closed electrically.
My previous layout was a donut. I DID cut the bus lines in the front (they connected to the DCC system at the back) because I was PLANNING to install circuit breakers to make multiple power districts - even had the bus lines (all 4 sets, it was a double track main) terminate in terminal strips with jumpers connecting them where the individual outputs fromt he breaker would connect eventually - but I did NOT cut gaps in the rails of the mains, just in the middle of the two corssovers that connected the mains, so I had two complete loops of track and absolutely zero operating issues.
What you do NOT want to do, and more of an issue of a waste of wire (and money) is to ADD an additinal bus run to complete a loop is say your layout is U shaped and linear - there is no need to run extra wire to connect the free ends of the bus back to each other. I can;t imagine anyone actually doing that, it's so non-intuitive to even think you might possibly have to do such a thing, Just leave the ends loose and secure them so they cannot short out on each other or something else.
Some systems recommend snubbers at the ends of long bus runs, other say they are unecessary. Out club modular setup is 130 feet long and 18 feet wide, and there is not a snummber in sight - and there are no control issues, runaways, or spontaneous decoder resets (other than when some joker isn't paying attention and calls up the same address of the loco you are running. Seems to happen mostly uth the utility throttles when someone uses one fo the club pool and when they are done doesn;t reset the selected address on it to al 0's (DC is disabled, so it won't run anything). That person comes back later and goes to run the same loco, but has grabbed a different throttle. Person B comes along and picks up the first throttle that Person A had used, and also fails to check the address selection, and plugs it in. oops.)
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
We should be very clear that you do not need to gap a layout to operate it in DCC. Not if it is only linear, and not if it is only a loop. Connecting any DCC system to any loop of track, no gaps, will not cause problems. Similarly, since such a loop would present no physical impediment to DCC operations electrically, the bus running under it could also be a loop. Simple logic. Just don't loop the two wires issuing from the controller base's output terminals to each other. Loop them back to their own output terminals where they originated. IOW, two loops, not one.
Crandell