QUESTION FOR DALE M.

I am not dale Jim and your theory seems correct but dirty wheels and rolling might be somewhat like a bad connection.  chief

For Jim and any others that still believe the engine picks up a signal radiated from the outside rails. At our club we use Gargraves track. One outside rail is insulated for signal purposes. Piror to the installation of Legacy we had occasional problems with TMCC reception that I believe was caused by the receivers in the engines. However, we had members that insisted that the problem was that insulated outside rail. They tried everything, capacitors, resisters, and even shorting the two outside rails together. Nothing worked! Now think, if the signal was radiated from the outside rail than wouldn't the best reception be obtained by simply connecting the antenna to the outside rail? If you do that you will kill any TMCC reception you have.

I do know and have heard of people seeming to get better operation when both outside rails are shorted together but I suspect this results from a better ground connection to the frame of the engine rather than better reception of the signal. One might obtain the same result by cleaning the track and the engine wheels.

Al

I was away for a couple of days.  Jim, adding a capacitor across the outer rails would probably be a good idea.  Part of the TMCC signal is conducted through the wheels to the frame and ground of the locomotive, and the capacitor would help with the reliability of that signal regarding dirty wheels and traction tires. 

The RMT BEEP is a good example - only 4 wheels, and one of those has a traction tire.  If the other wheel on the side with the traction tire is dirty, you don't have much to conduct the signal.  If you run the BEEP without any cars, you may be in trouble.

There is also the possibility that your signal sensor circuit may already provide a path between the two rails at high frequencies, but that would depend upon your specific circuits.

The wheel sets of the cars will also help, but I have had some really dirty wheels that I wouldn't count on their conductivity.

Thank You Guys for the response. Our layout is running a little better these days. We had a member run an engine on one of the lines on the layout the other night. The engine kept stopping at a couple of locations. He added some cars behind the engine and the problem went away.

         We got the layout to run better TMCC wise by adding another earth ground wire.

We had a #12 wire running under the layout acting as an earth ground buss, the wire went to the fire sprinkler pipe. It got to a piont that when we attached another earth ground wire to the #12 wire to fix one spot a problem would come up in another location. I divided the layout in half and ran a #10 from under the layout the the fire sprinkler pipe. The other half of the earth ground wires go to the # 10 wire. This helped. It seemed the # 12 wire was over loaded. I know there is no current or voltage going through the wire but that seemed to be the case. Thanks again. This is how we keep learning how to solve the TMCC problems.

Jim D.

Pin 5 on the 9-pin connector is the best point to pick up the 'earth ground' side of the signal.   That is where the true 'ground' in the Command Base is connected.   In comparison, the sprinkler pipe is quite a ways away (electrically) from this source of the 'ground' signal component.

I would be really curious to know what would happen if you disconnected the #10 wire to the sprinkler pipe and instead tied your grid directly to Pin 5.  (Any COM wires used for accessory or power control devices are also ground signal radiators connected to Pin 5!)

Your problem with the engine mentioned stopping may have nothing to do with the TMCC signal on one or both outer rails, but rather with the power flow through too few good wheel connections.

The Legacy base and command base are plugged into a Hospital outlet. It has an isolated ground. It is grounded to the #12 wire that goes to the sprinkler pipe. The electrical pannel the the layout runs off of is also grounded to the same pipe.

Jim D.

Pin 5 is a much more direct route to inject the signal into the auxiliary ground signal grid.  It is comparable to walking to the end of your driveway vs. driving around the block to get there.

I'll be in York this week, but I will give it a try next week. Thanks.

Jim D.