The steamer is the C-II Empire State Express Hudson, and the diesel is UP 3593, the 'Desert Storm' SD40-2, circa 2003. Both Lionel.
Each has the same behavior: Loss of TMCC signal at many places. [Both ran well in the past, and the layout is, and has been, ‘stable’.]
Each has been re-programmed; each has had a swapped radio board. No change.
My usual ‘fix’ , for MANY engines, is to add more antenna, which I did. In fact, after this failed, I even REPLACED the original antenna with 8 - 10” of new wire. [For the steamer, this removed the handrails as a possible culprit. For the diesel, it entailed removing the small, metal plated that was sitting atop the various PCB’s.] Each was connected to the original, short wire coming from the radio.
And now for the final results, and the NEW PUZZLE: Both run perfectly WITH THE SHELL OFF! They are ‘crappola’ with the shell on; just as bad as when the problems began…..….
To conclude, my last experiment DID achieve PERFECT TMCC for the diesel. This entailed running my new antenna wire up thru the cab, out the front window, and sticking ~ 2" vertically above the roof. Ugly, but effective.
I believe that these problems are unique....But if not, may some one out there can help me!
Something must be killing antenna signal when shells are on. So if base is perfect and track signal is great, has to be an engine issue. Antenna or R2/4LC. G