Legacy and DCS WAR

Sounds like weak DCS signal from the TIU. Have you performed a signal check using your various MTH engines (obviously with Legacy disabled since you are getting interference). Also, what revision of TIU hardware do you have (label on bottom)?

For the most part, the 2 should coexist fine, and the 2 noted exceptions are when using say a TMCC booster to crank up the TMCC radio signal can interfere with DCS track signal, or the other way, an already weak DCS signal so weak that even the non boosted output of a TMCC base can interfere.

Have you already installed 22uH chokes on all of the non-DCS locomotives and all powered rolling stock such as passenger cars to prevent them from attenuating the DCS signal? 

@Porschev posted:

Have you already installed 22uH chokes on all of the non-DCS locomotives and all powered rolling stock such as passenger cars to prevent them from attenuating the DCS signal?

With only two locomotives on the track, one Legacy and one DCS since this is a simple test, and no passenger cars, the 22uH chokes should not be necessary -- yet.

They might indeed be needed, as a final fix, however.

Mike

First thing to check, is this an issue if just the Legacy command base is connected and operating, or only if there is a Legacy locomotive on the tracks?

As others have stated, you might have a DCS signal strength issue.  Sadly, the simple method of using a DCS engine to measure track signal is far from a definitive DCS signal test, you really need to measure the output of the TIU via a more direct means to see if the signal is degraded.

FWIW I, and a host of others here, run DCS and Legacy/TMCC together seamlessly, so this is not a problem that is universal.  I have run DCS and Legacy locomotives on the same tracks at the same time with no signal issues, at least none that affect operation.

Didn't @Engineer-Joe have similar problem with the legacy system reducing the DCS signal?  I think he made a video on it.

@H1000 posted:

Didn't @Engineer-Joe have similar problem with the legacy system reducing the DCS signal?  I think he made a video on it.

I forgot about that.

it became an issue because of wiring changes. I had TMCC connected to one handle of a Z4000. Somehow that messed up the mains on a different loop. I forget exactly but had something to do with the common return wiring inside the tiu?

I blamed it on my 2 rail use.

There is an issue that can come up with DCS and TMCC/Legacy, but usually unless you have an unusual wiring scheme, they work out.

I recall Adrian giving a demonstration of how a TMCC/Legacy signal could disrupt the DCS signal from time to time. I don't recall if he worked on a detector that would temporarily shunt the TMCC signal when a DCS command was sent. It was an interesting analysis that's beyond my RF expertise.

Are you already using all of the TIU ouputs? If not, maybe try another channel(?).

@AGHRMatt posted:

I recall Adrian giving a demonstration of how a TMCC/Legacy signal could disrupt the DCS signal from time to time. I don't recall if he worked on a detector that would temporarily shunt the TMCC signal when a DCS command was sent. It was an interesting analysis that's beyond my RF expertise.

We had a lot of discussion on this, but I don't believe that Adrian came up with a working prototype yet.  I believe usually the interference between Legacy and DCS is more of a problem on large or poorly wired installations.

First step would be to check the signal strength of the DCS signal.  Many of us use this TIU Output Signal Tester for a quick snapshot of the DCS output.

Where might I  acquire a TIU Output Signal Tester like the one you show?Thanks

I believe that Tom @rtr12 still has some parts for kits to make these.   Check with him and see.

Yes, I do still have some TIU Port Tester kits.  To anyone that's interested, please email me at the email address in my profile.