DCS Signal Strength?

Bob,

Too many engines means too much of a power demand. This can cause problems with signal strength.

I have each engine on a power-switched siding and only power on those than I'm actually using in an operating session.

Barry, even if the engines haven't gone thru the start up procedure?

One other thing I've noticed, with all these engines on the layout I sometimes get one that starts up on its own.  I can usually press shut-down for that engine and it'll stop, but sometimes I have to turn off the power and remove the engine.

I knew I needed to add toggle switches anyway, so maybe that'll fix it, thanks!

The only reason I was keeping so many engines on the layout was that I don't have enough shelf space to store them.  Maybe I'll cut it down to 3 and see if that fixes things.

Bob,

 

even if the engines haven't gone thru the start up procedure?

Yes.

One other thing I've noticed, with all these engines on the layout I sometimes get one that starts up on its own.  I can usually press shut-down for that engine and it'll stop, but sometimes I have to turn off the power and remove the engine.

Same issue.

I just tried adding engines back onto the layout, one at a time.  I now have 3 on the layout and no issues with track signal strength, all 10 and no unwanted start ups.  I may add one more, but 4 will be my limit until I can install some toggle switches.  I still may run some wires over to the east side of the layout (let me see if I can add the photo now):

Thanks again Barry

nope

something's up with my browser this morning and I can't see any pictures or attachments, so I don't see the diagrams posted.

 When I added my engine yard, I got the same results at first. I added another TIU channel and just used a jumper on the input side because I didn't have another power brick. I connected this new channel to the yard tracks.

 The signal went right back to tens everywhere. My mainline is so large, that adding the yard tracks full of engines, stole the signal strength. Once another channel was added on the same brick, all was well. I have since changed to a version L TIU and removed the bulbs to the yards.

 When I get more than twelve ten or so engines in the engine yard terminal, I still get some missed watchdog startups and lower signal problems. I added switches to kill some yard tracks to solve. Adding more channels would have helped.

Bob, for your diagnosis, place a loco, stopped but powered up, in an area where the signal issue seems to be greatest.  Turn off, with the toggles, all sidings.  Set the engine to give signal strength.  Turn the toggles on, one at a time, and see what happens to the signal strength.  If turning on a toggle causes signal strength to drop, place a bulb across the end of that siding. 

This is what I did when I built/expanded the layout to add an area with many sidings and had signal problems; cured all signal problems.

Note I did not say to put the loco on the suspect siding.  I have found that turning on power to some sidings, even with nothing on them, can pull down signal strength elsewhere.

Another possibility is that if any of these locos are not DCS, they may have constant voltage boards which kill DCS signal.  Some cars also have these boards for lighting.

I strongly recommend against tackling rewiring, unless you layout uses #18 gauge wire or smaller.  My layout was built long before DCS, using 14-gauge feeds and common buss ground.  Tweaking as described above solved all signal problems.

What part of VA are you in?

RJR,

Haven't installed toggles yet, but will and will try what you suggest.

All of the engines on the layout are PS2, no lighted cars currently on either.

It didn't occur until I added the TT and changed the trackage around it, before it was about the same amount of trackage and close to the original locations.

I can see the layout plan now so maybe they fixed whatever was going on this morning.

I'm fairly sure that your problem is what I encountered when I expanded and added sidings.  It's weird, some sidings had major effect and needed a bulb, while an adjoiinng siding would have no effect when turned on.

By any chance, are using Rev L TIU?

Rev L is the one I have.

I knew I should have bought some toggle switches at the local NMRA train show last month

Buying standard electric components is like buying something at a marine supply house; price is multiplied.  Try online at Mouser.

For our yard on our modular display layout, I installed a 13A RF choke in series with the common switched power for each track.  I have a rotary switch to select the track that will connect to a TIU channel to provide DCS capability to that yard track.  The TIU is run in passive mode for the yard so there is no input side power to the channels.

To energize a track, we set the rotary switch to the track and turn on the power to that track.  Works great, we get the DCS watchdog and power to the track.  The choke prevents interference between TIU channels.

That may be why I didn't buy any!

John, is the TIU you're using only tied to the yard or is it used elsewhere on the layout?  In other words, could 1 channel of the TIU be used in passive mode and the other(s) used normally?

This is off topic (I can do that on my own thread right?) I tried my 2 Variable channels again in Fixed mode and neither worked (the engine starts automatically after a couple of seconds with sound and lights) but I can't change speed (it just sits there) and no other pushes of any buttons make a change.  I'll get hold of George later to see if he'll take a look.

What part of VA are you in?

Portsmouth, across from Norfolk.

Yep, no problem using a channel in passive mode and others powered.  I settled on switching the TIU just to the individual tracks so that I could be sure of a good DCS signal to add engines in the yard before we drive them out onto the mainlines.  Since the channel gets powered as the track is powered, I get the watchdog signal for the track when power comes on.

Just a possibility: Did you set the DCS Channels To All On for this? With the Variable Channels, the DCS signal may be turned off.

Russell, if the variable channels are turned up full, they output the same waveform as when they're in fixed mode.  However, if they're not at 100% voltage, you would indeed get a more "chopped" waveform.

Russell,

I followed Barry's instructions (down near the bottom) from this topic:

https://ogrforum.ogaugerr.com/topic/power-to-tiu-1

I've had this problem for at least a year, thought I'd try again for "S's & G's".  They work fine in conventional (if I recall correctly, I no longer have any conventional engines), just not in command.

 On both my older tiu and the new L that replaced it, I followed Barry's instructions and turned the variable channel to fixed. I jumpered the inputs from fixed one or fixed two to the variable 1 or 2 (set fixed) and it worked.

 I just would guess that something's being overlooked. Unless somehow the generators for both variables got cooked? I would bet something got messed up with the remote changes to the tiu, somehow??