best TMCC antenna configuration.

Use the handrails.

For a plastic shell, a long strip of adhesive backed copper works well.  And, as Marty says, if it has metal handrails, they're an obvious choice, the extend the length of the shell.  For a diecast shell, the handrails are the usual choice, but you may have to replace the stanchions with plastic ones, I've done that on a couple of steamers.

I realize the plastic doesn't block the RF, but the handrails are already there.

  Thanks for the advice!  I had already applied the copper strip in the roof.  Seems to be working very well.  If I encounter any problems, I will shift to handrails.  Should the handrails be connected at one end to form a single antenna twice the length of the body?  I'm pretty sure attaching together at bot ends would create a loop, cancelling the signal.  Is that true?

On Lionel units, each hand rail is electrically isolated from each other.  Then one end of each handrail is wire nutted to the antenna lead from the board.  So effectively you created a Y.  The only place they are electrically connected is at the wire nut.

That is the way they are for the engines I have.  I'm sure configurations vary based on the way the handrails have to be applied to mirror the prototype.

The ones I've opened are like Marty says, they have two wires individually from each handrail and they join at a common point.  The last one I worked on was a K-Line Mikado, and it joined to a single wire that then had the plug for the TMCC motherboard at the end.

There is no cancellation if you wire both ends, middle or anyplace else, or use a solid sheet such as foil tape or a slab of metal.  The antenna is tiny compared to the 2000' wavelength of the radio signal.

I think the basic guideline here is make the antenna as large as you can.

gunrunnerjohn,  Where do you get your plastic stanchions from? 

Thanks, Marty

I'll have to give that a try sometime, but I still had to replace the stanchions since the others were metal, not really good for isolating the antenna!

Hmm... Looks like some fairly corrosive stuff, you'd have to do some through cleaning!

Its less corrosive than acid flux. I just rinse it off with plain water and blow dry.

Pete

In this pic, you can see what I use when possible. It's the lamination from a CW 80 watt transformer mounted above the old Railsounds commander II. I don't know if its the best antenna, but it works for me.

Bill