Is it necessary to wire RX4's to the Digitrax BDL168? Some Digitrax Decoders and some other 3rd party decoders have transponding in them.
Only if you want transponding. The BDL168 does detection all by itself. Also, i don;t think any third party decoders actually have trnasponding, they are just 'transponding compatible' meaning they won't eat up the signal and you can install one of the Digitrax TL decoders alongside them to get Transponding.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
What is the difference? Is the transponding diffrent from the locomotives with transponding equipped Digitrax decoders.
Transponding decoders report which loco it is, to a BDL168 with RX4's. The BDL168 by itself can detect something in the block, but not specific loco, just that something is there.
Transponding it pretty touchy, in that it has to be wired exactly as described, including the spacing of the RX4 from the BDL168 and so forth.
How can the wiring distance be limited. Thanks allot for your help.
See the instructions for the BDL168 and RX4, also there is a Transponding App Note on the Digitrax web site. The distances mentioned are the spacing of the RX4 from the BDL168, and how the wires get run to the blocks. The Transponding signal is very weak relative to the DCC track signal, and can easily be swamped, so there are very specific wiring diagrams that need to be followed.
Block occupancy and transponding are two different things.
Block Occupancy: By detecting a change in current, the BDL detects that "something" is occupying a particular block of track. But that "something" is dumb. It doesn't speak up to identify itself. In fact, it might not even be a train at all.
Transponding: The Digitrax decoder transmits "I am here" signals. Depending on how you wire your BDL and RXs, "here" might be somewhere within a zone of blocks, or within a specific block, or on several blocks. For example, you might want to know "what" is occupying each of your sidings in a yard. If you are using Digitrax decoders then they can transmit the necessary signals back to the RX. Transponding technology is available for licensing. Digitrax has developed decoders for Kato with the technology.
The "opposition" product is RailCom and RailCom Plus, both developed by Lenz. These products are equally as good but not compatible with Transponding.
Wiring is something you shouldn't be skimping on. There are plenty of threads on appropriate wiring thickness and I recommend you stick with the Digitrax standard as a minimum.
If you're asking about placement of BDLs to minimise wiring then the answer is simple: fix the BDL to the underside of the base board, close to the zones and blocks that you want it to cover. This is because there are fewer input wires than output wires, so if you're going to have a long run anywhere, you want it on the input side of things.
Mounting the BDLs under the base board means you need to plan ahead with your wiring and programming. I use the Accu-lites breakout boards for easy wiring. I keep one beside my programming track so that I can program the BDL on the work bench before installing it.
If you are using the RR&Co computer program for your system control, you don't need transponding. The program can keep track of your locomotives. You will have to study the instructions to figure it out. I don't have the program myself, I just know that it says that it will do it.
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.
Thanks for all of your help and input