Experiment with grounds

There is probably enough coupling from third (ground) wire to the hot or com wire for it to work.

Do you have ABSOLUTELY NOTHING connected to the 9-pin serial port on the Base?  An wire attached to that point can act as an effective radiator.

Kerrigan posted:

Just for giggles we took an old extension cord, one without the green ground prong, and hooked it up to the TMCC wall wart.  TMCC worked fine all over the layout.  Then we reversed the cord, so the current is now the common, and the common the hot side .. and TMCC still worked great all over the layout.

Looks like the "grounding prong" in the wall wart is non-functional outside providing a grounding path should the wall wart short out internally.  Only two wires going from it to the TMCC brick ... no "ground" provided.  Just the "+" and "-" legs I guess.

Then we ran a DCS locomotive on the same track as a TMCC locomotive, using the DCS handheld for the DCS engine and the Big Red Wheel for the TMCC engine.  No conflicts; they both ran fine with each other ...

Nice to not have problems ... for a while at least!  lol!

Currently debating putting the ground plane wire under ALL the upper level tracks, or just where they cross over another track ... but it will all have to be connected anyway so why not just wire the entire upper tracks?

You and Phil need to get JOBs!  Too much free time on your hands  G

Dale Manquen posted:

Do you have ABSOLUTELY NOTHING connected to the 9-pin serial port on the Base?  An wire attached to that point can act as an effective radiator.

Nothing.  No wire.  Seems to work fine without a "ground" ... maybe even work it the middle of an open field (no  house wiring) with a long non-grounded extension cord ...

GGG posted:

Kerrigan posted:

Just for giggles we took an old extension cord, one without the green ground prong, and hooked it up to the TMCC wall wart.  TMCC worked fine all over the layout.  Then we reversed the cord, so the current is now the common, and the common the hot side .. and TMCC still worked great all over the layout.

Looks like the "grounding prong" in the wall wart is non-functional outside providing a grounding path should the wall wart short out internally.  Only two wires going from it to the TMCC brick ... no "ground" provided.  Just the "+" and "-" legs I guess.

Then we ran a DCS locomotive on the same track as a TMCC locomotive, using the DCS handheld for the DCS engine and the Big Red Wheel for the TMCC engine.  No conflicts; they both ran fine with each other ...

Nice to not have problems ... for a while at least!  lol!

Currently debating putting the ground plane wire under ALL the upper level tracks, or just where they cross over another track ... but it will all have to be connected anyway so why not just wire the entire upper tracks?

You and Phil need to get JOBs!  Too much free time on your hands  G

Phil's an Engineer ... thus all the in-depth "research!"

Kerrigan posted:

Dale Manquen posted:

Do you have ABSOLUTELY NOTHING connected to the 9-pin serial port on the Base?  An wire attached to that point can act as an effective radiator.

Nothing.  No wire.  Seems to work fine without a "ground" ... maybe even work it the middle of an open field (no  house wiring) with a long non-grounded extension cord ...

Actually, I think what Dale is saying is that there is a wire...just not obvious, even if it's just a few inches long in the device and what couples to other wires. If it works and it's ok to run the trains reliably, then good.

No, I am asking if there is nothing plugged into the Base 9-pin serial port.  Things like ZStuff Data Wire Drivers and cables to TPCs or other serial devices all contain a ground wire that can radiate.  Even the Legacy Y Cable has ground wires in both branches.

Yes, the wallwart cable is a radiator.  I also tried to measure the leakage impedance through the wallwart, but my vector impedance meter didn't give a reliable reading.  That would provide some coupling to the house wiring.

Dale Manquen posted:

No, I am asking if there is nothing plugged into the Base 9-pin serial port.  Things like ZStuff Data Wire Drivers and cables to TPCs or other serial devices all contain a ground wire that can radiate.  Even the Legacy Y Cable has ground wires in both branches.

You mean the cable connected to the #1 TIU and the TMCC box?

PLCProf posted:

Well, heck, the command base cord to the wall wart has the pin 5 connection (or equivalent) in it, no? Isn't that the path to the house ground?

From the wallwart to the TMCC box there is a two-wire connection, one + and the other -, as it's DC current, correct? 

Actually it's 8 VAC, but it's also the ground wire antenna side of the signal thru it's outside sleeve connected to the ground pin on the wall wart plug.

cjack posted:

Actually it's 8 VAC, but it's also the ground wire antenna side of the signal thru it's outside sleeve connected to the ground pin on the wall wart plug.

The sleeve on mine apparently is plastic with just two wires.  Didn't know it was AC .. so the current really just sits on one place oscillating back and forth, correct? DC is a directional current flow ... ?   I was also thinking of connecting a ground plane to just the grounding prong on a plug and then sticking in the floor socket.   Believe that is connected to the house ground from which I gather the excess signal will be sucked to the house ground.  Right?

Ok...sleeve refers to the outside cylinder of the plug that goes into the base. As for the physical descriptions of current flow, they're mostly for understanding the effect of what's happening. No. The ground wire is not as you suggest, but is in fact an antenna from which the engine antenna receives it's signal. The word "ground" is unfortunate since the ground wire is only being useful as an antenna wire. Ground "plane" is also not meaningful in this system.

Careful sticking anything into an AC socket. I know you only intend to make a connection to the ground pin and thus the house ground wire, but stay aware of the voltage potentials just a fraction of an inch away.

You have already proven that the signal is radiated from any wire it can find that is connected inductively or otherwise to the transmitter inside the base. That's all there is to it.

Light travels 2498266 meters in 1/120th of a second, so the electromagnetic waves have left the building.  They can be slowed down, depending on the conductor, but they'll be moving along at around half the speed of light most anytime.  Electron flow in a conductor is much slower, for 60hz power, the electrons never move more than a fraction of an inch in the conductor.

As Chuck says, this is all esoteric stuff that really doesn't help one deal with the everyday problems with TMCC and signal propagation.