Signal noise problems with WTIU and TIU with WIU

Do you know what the DCS signal integrity is when the problems occur; X/10?

Have you considered trying a power conditioner dedicated to your layout?

The reason I ask is the DCS signal is susceptible to line noise from the power source.  If there's a lot of noise on the 120V side, that passes through the train transformer and TIU/WTIU and gets superimposed on the DCS signal.  That can confuse the trains trying to decode the DCS signal.  Case in point, there have been recent discussions here on the forum about how the WTIU seems to have problems when powered by transformers with less than a pure sine wave output.

A suitable Line Power Conditioned filters out the noise and passes a much cleaner 60Hz 120V sine wave onto whatever's plugged into it's output.  In this case your layout.

I would normally never say this: what about DC power?

If you are running largely off grid, and you have a large MTH collection, and DCS, then those are DC compatible- one of the new selling points of the WTIU.

Caution- you then need to ensure you never put something Lionel or Lionel related (example K-line or something like an ATLAS with TMCC) because those electronics may be AC only and damaged by DC.

Again, normally, I don't recommend DC for O gauge because so much equipment is AC only- everything from sound cars, operating cars, a whole swath of TMCC era equipment that needs the zero crossing of AC waveform in order for the TRIAC outputs to turn off.

@Walter Bell posted:

Hi everyone,

The problem does not occur when I set up the TIU without the WIU, using the MTH remote.

---

Also, for the WTIU- we have a solution that works for this with the DCS remote. Simple adapter anyone can build. https://ogrforum.com/topic/rtc...en-a-remote-and-wtiu

Thanks all for the suggestions. I will look into the power conditioner.

But does ayone have a guess as to why the problem does not exist on the TIU running without the WIU using the MTH remote? It seems like on the surface that the electronics talking to the engines would be the same whether the "back end" function of connecting with the remote function was to the MTH remote or to a smart phone over the wifi connection?

@Walter Bell posted:

Thanks all for the suggestions. I will look into the power conditioner.

But does ayone have a guess as to why the problem does not exist on the TIU running without the WIU using the MTH remote? It seems like on the surface that the electronics talking to the engines would be the same whether the "back end" function of connecting with the remote function was to the MTH remote or to a smart phone over the wifi connection?

That pesky problem of the app sitting on top of a 3rd party OS- hoping it's data packets go out the WIFI interface, not the cell data interface, hope they arrive at the WIU, hope it translates it to serial communications to the TIU- hope the TIU sends it to the engine, hope the engine responds in time, hope that response gets back to the TIU, hope the TIU sends the response out to the WIU, Hope the WIU sends it out back over the WIFI- hope it actually gets to your 3rd party device, hope the networking layer gets it to the app- all before it times out.

What could ever possibly go wrong........................

EDIT- the think the amazement is misplaced. You get angry because it doesn't work sometimes, you should be thrilled it ever does it right even once.

You haven't mentioned the signal the engines are getting when the issue occurs.  Are they all 10s?

I"ll check on the signal levels when I am back up at my layout location. It's 35 miles away up in the mountains where I used to live. In looking into signal conditioners, I believe I did try that a few years back at the same time I tried the isolation transformer.

The DC power approach is interesting, All my engines are MTH of PS2.0 (5V) or later. So they can all run with DC track power as well as DC input power to the TIU? I assume that is what you get to the track if you put DC into the TIU.

Thanks everyone for the suggestions!

@Walter Bell posted:

I"ll check on the signal levels when I am back up at my layout location. It's 35 miles away up in the mountains where I used to live. In looking into signal conditioners, I believe I did try that a few years back at the same time I tried the isolation transformer.

The DC power approach is interesting, All my engines are MTH of PS2.0 (5V) or later. So they can all run with DC track power as well as DC input power to the TIU? YES- that's why I said it was an option.

I assume that is what you get to the track if you put DC into the TIU. YES, DC in = DC out- it's not an inverter capable of making AC from DC.

Thanks everyone for the suggestions!

From the DCS manual (From the TIU) much applies to the WTIU https://ogrforum.com/fileSendA...%205th%20Edition.pdf

And there lies at least one issue- the new abbreviated WTIU start guide is not a complete manual. Users need to go back and at least be familiar with the older DCS/TIU manual and a lot of people haven't read it.

Yery true!

@SteveH posted:

Have you considered trying a power conditioner dedicated to your layout?

That's exactly what I use with my layout.

Well thanks to everyone's suggestions, I had a major breakthrough yesterday using the Track Signal feature (thanks Steve for that suggestion) to locate a fault in the wiring of my main loop. Despite over 15 years of running MTH trains, I was unaware of this feature until Steve asked about my signal levels. By measuring Track Signal around my main loop, it became quickly clear that in wiring my removalable duck under bridge, I had failed to connect both sides of the bridge, creating a section of track with severe reflection noise from the break in the loop. Fixed that and the signal levels went from unmeasurable up to 6 in that spot to 10s. So it was this dufus wiring mistake rather than any power problems, as the layout now performs well with generator or inverter power.

As a further improvement, after reading the DCS manual again (thanks Vernon for the prompt), I realized I was exceeding the suggested five powered locos max per loop with my engine storage yard area. Will be putting some power switches on that yard to cut down the powered locos in the yard.

Thanks again to everyone's help!

@Walter Bell posted:

Well thanks to everyone's suggestions, I had a major breakthrough yesterday using the Track Signal feature (thanks Steve for that suggestion) to locate a fault in the wiring of my main loop. Despite over 15 years of running MTH trains, I was unaware of this feature until Steve asked about my signal levels. By measuring Track Signal around my main loop, it became quickly clear that in wiring my removalable duck under bridge, I had failed to connect both sides of the bridge, creating a section of track with severe reflection noise from the break in the loop. Fixed that and the signal levels went from unmeasurable up to 6 in that spot to 10s. So it was this dufus wiring mistake rather than any power problems, as the layout now performs well with generator or inverter power.

As a further improvement, after reading the DCS manual again (thanks Vernon for the prompt), I realized I was exceeding the suggested five powered locos max per loop with my engine storage yard area. Will be putting some power switches on that yard to cut down the powered locos in the yard.

Thanks again to everyone's help!

Please explain what you mean by "failing to connect both sides of the bridge" and "refection noise". Failing to connect both sides outside rails? I would assume if you have track blocks, failing to connect center rails is not an issue as long as both blocks are powered with similar wire lengths.

Mike

Hi Mike,

The main loop is one block that is powered by one channel of the TIU. The error in wiring is that there was no connection of any of the three rails on one end of the bridge to the rest of the loop. This error broke the loop into two long stubs. Track signal values were fine everywhere except on the section of track on one side of the bridge. My belief is that the reflection from the two stubs was much worse on the end portion of one of the stubs because of the length of that stub. Note that the feed from the TUI was not exactly in the middle of the broken loop. Since I didn't need this loop to broken into two stubs, the simple solution was to connect the break in the loop connecting both ends of the bridge to the loop thus eliminating the stubs all together. I do have some shorter subs off the main look in a yard area, but these do not seem to be causing enough reflections to create poor track signal levels.

Comments/corrections are welcome

Walter

@Walter Bell posted:

Hi Mike,

The main loop is one block that is powered by one channel of the TIU. The error in wiring is that there was no connection of any of the three rails on one end of the bridge to the rest of the loop. This error broke the loop into two long stubs. Track signal values were fine everywhere except on the section of track on one side of the bridge. My belief is that the reflection from the two stubs was much worse on the end portion of one of the stubs because of the length of that stub. Note that the feed from the TUI was not exactly in the middle of the broken loop. Since I didn't need this loop to broken into two stubs, the simple solution was to connect the break in the loop connecting both ends of the bridge to the loop thus eliminating the stubs all together. I do have some shorter subs off the main look in a yard area, but these do not seem to be causing enough reflections to create poor track signal levels.

Comments/corrections are welcome

Walter

It makes sense. Thank you for taking the time to explain.

Mike