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  • Topic: Wireless DCC

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    • August 30, 2018 5:20 PM EDT
      • Pittsburgh, Pennsylvania
         
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      Red said:
      ................. its a minefield of poorly explained info out there.

      Yes, and that is shame. How is someone new to this technology supposed to get started, without wasting good money?

      It would be great if there was a uniform standard as in the smaller scales.

      Yes. yes it would be.......

       

      ____________________________________

      Shannon car Shops
      Home of the infamous leg lamp

      I.A.R.R.R. Member #12

      and King Butt Modeler

    • August 31, 2018 2:35 PM EDT
      • Be Nice or STFU
         
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      Red said:

      I've had feedback from NCE and CVP. Both advise of compatibility issues between the NCE GWire cab and CVP receivers. So I'm now in the market to sell one never used throttle and 6 QSI Gwire receivers! 

      I'm finding it difficult to select a new system, its a minefield of poorly explained info out there. It would be great if there was a uniform standard as in the smaller scales.

      Well, you are looking at something that is relatively new, trying to move DCC, which is defined as a system with certain components, a certain architecture, and track power; to wireless, and eliminating certain important architectural details.

       

      This is no different what the scale, there IS no standard.

       

      DCC as defined by the NMRA is more than just the protocol, but certain functions, where a central command station is the only unit transmitting commands. This has been bypassed in most implementations. This creates unique problems that different people solve in different manners.

       

      Since there is very little battery power used in all the DCC systems that exist, it would seem that this is the reason no one has determined a standard. Only in the last few years have people tried to "inter operate" between hardware from different manufactures in WIRELESS DCC implementations.

       

      The fact that Airwire has violated the most fundamental issue, the actual timing of the protocol, shows that these manufacturers are really not interested in a universal standard.

       

      So you are really seeing this in it's infancy, in ALL scales.

       

      Greg

      This post was edited by Greg Elmassian at August 31, 2018 2:37 PM EDT
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    • August 31, 2018 6:06 PM EDT
      • Kittery, ME
         
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      The Airwire T5000 throttle is in spec.  Here is a plot of an RF capture (top) and frequency threshold plot (bottom), showing the symbols.  The overlay in white averages the symbol rate, and you can see that the 1s are very consistent, and the timing of each half of the symbol is 55.75 µs.  The command station spec is 55 to 61 µs, and decoders must accept 52 to 64 µs.

       

       

      Perhaps Stan measured older equipment, but the current transmitter is dead on.  Any DCC decoder should easily understand what the T5000 is sending.

    • September 1, 2018 7:29 AM EDT
      • Chelmsford, MA
         
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      Eric Reuter said:

      The Airwire T5000 throttle is in spec.  Here is a plot of an RF capture (top) and frequency threshold plot (bottom), showing the symbols.  The overlay in white averages the symbol rate, and you can see that the 1s are very consistent, and the timing of each half of the symbol is 55.75 µs.  The command station spec is 55 to 61 µs, and decoders must accept 52 to 64 µs.

       

       

      Perhaps Stan measured older equipment, but the current transmitter is dead on.  Any DCC decoder should easily understand what the T5000 is sending.

      Eric

       

      Great news!  I stand corrected.

       

      Indeed I did the test many years ago when we were working on a standard for DCC direct.  At that time they were transmitting the  1 bits at 9600 which resulted in one pits slightly under the standard.  I had not realized that they redid the bit transmission in later versions. (you can actually transmit DCC using standard ACSII using a serial port at 9600 but that is another topic)

       

      We came close to completing the standard for DCC direct but alas the DCC working group ran into other problems about that time and lost the wide manufacturer participation.

       

      Stan

    • September 3, 2018 6:49 AM EDT

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      Hi Eric, by being within spec I assume you mean within spec to send signals to their receivers which work with any decoder made in line with NMRA DCC protocol?

       

      So now I need to find out about 900Mhz versus 2.6Ghz - (range, interference with other electronics, , interference by other electronics), which frequency equipment is approved for use where I live, which systems have built in sound and which do not etc. Hardest of all, finding out which systems will be around for a long while - I have already burnt my fingers with QSI before getting even one loco to run.

       

      It seems that the locomotives are the cheap part, the control, sound and battery systems are the expensive part! Right now I run a loco with a $4 LED light driver with forward only; the motor makes a ringing sound like a DC loco on a DCC system set to the short loco ID reserved for non DCC - at least it goes!

    • September 3, 2018 7:15 AM EDT
      • Kittery, ME
         
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      Hi Red - Yes, that's what I mean.  CVP makes their own decoders (G3, Drop-In, etc.) that combine a radio receiver and DCC decoder on one board.  They also makes a product called Convrtr that is just the receiver portion, and generates a DCC output that you can then hook to any standard DCC decoder.  The DCC signal originates at the throttle, so it's important that the throttle generate an NMRA-compliant DCC bitstream.  The current throttle that they sell is compliant, but Stan found that the ones they made several years ago were slightly out of spec.

       

      As far as the two frequency ranges go, lower frequencies are generally able to propagate more easily through and around things, so 900 MHz is theoretically better that 2.4 GHz in this regard.  In reality, though, the difference is probably negligible compared to other factors like transmitter power, antenna gain, etc.  

       

      I chose Airwire because I like to hack and build my own devices.  As it uses DCC, this is much easier than trying to reverse-engineer a proprietary protocol.  Another benefit of DCC is that you can piggyback receivers to add function outputs.  One of the serious shortfalls of the new RailPro system is that it only has 6 outputs.  Once you hookup front and rear headlights, classification lights, and number boards, you're done.  No cab light, servo couplers, ditch lights, mars light, etc.  If you're ok with that limitation, it's probably the most user-friendly interface.  I have never used Revolution, so I can't comment on that system.

       

    • September 3, 2018 7:34 AM EDT

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      Thanks Eric. Your comments are most helpful! I'm compiling a spreadsheet of the different systems to make sense of them all, at the end of the day everything is a compromise of one sort or another.

    • September 3, 2018 10:05 AM EDT
      • Penacook, New Hampshire
         
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      Hi Guys, this is the first version of the RailPro module with 6 wired lighting outputs and 8 more software outputs for sounds or lights. I remember when the AirWire G2 was released it had 6 outputs.  Tim Ring has stated he will be adding more outputs in the next version.  

      Ring Engineering has been around for 14 years and started in the HO market. If we continued to support his G scale module we can ask for more options in future releases. He provided a download for the Phoenix and Lionel/MTH remote coupler and o different ditch lites flashing sequences. 

       

      Don

    • September 3, 2018 10:09 AM EDT
      • Peoria, NW of Phoenix, Arizona
         
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      Eric , I keep reading about a short range and losing  control of a locomotive with Airwire, do you have any problems with that?

      ____________________________________

       

      Butt Modeler #2

       

       

    • September 3, 2018 10:59 AM EDT
      • Kittery, ME
         
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      No, I haven’t really had any issues. You have to set the transmitter power higher if you’re going to be far from the engine. I do wish that the T5000 throttle had a proper antenna instead of the PCB antenna on the modem. 

       

      Another consideration is that it’s an ISM band and is crowded in some areas. You may have to find channels that don’t suffer from interference from other devices. 

      This post was edited by Eric Reuter at September 3, 2018 11:05 AM EDT
    • September 3, 2018 11:17 AM EDT
      • Gig Harbor, WA
         
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      Red,

      All this tech talk is very interesting and I have great respect for the knowledge that some folks have on this forum.  But, in my opinion there is nothing like some hands on with the different systems.  If you can find a way to visit some layouts and run some trains it might go a long way in helping you decide.  I don't know where you are located but you certainly would be welcomed for a visit.  I have been using Airwire starting with their very first product releases many years ago, some of those first decoders are still operating.  I now have over thirty locos with Airwire and Phoenix sound.   I don't think there is a "best" system, just what is best for you and the way you want to operate.

      ____________________________________

      Paul Burch

      Sierra Cascade & Pacific RR

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