Is the TMCC track signal bi-polar (like DCC)? Or is the common rail always negative?
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There is only one signal element on the track, the other part is over the air from the earth ground.
And just so I get it, is one rail constantly negative, while the other rail sends signals that oscillate between 0 and 18? Or are both rails oscillating between 0 and 18 (comparable to what happens in DCC)?
3RaylFan posted:And just so I get it, is one rail constantly negative, while the other rail sends signals that oscillate between 0 and 18? Or are both rails oscillating between 0 and 18 (comparable to what happens in DCC)?
Confused. Are you asking if TMCC and Legacy both use AC powered track?
They do, the tracks are not DC if that is your question.
The TMCC signal at 455 KHz is superimposed on the 60 Hz track power. One half of the signal is on the track and one half is in the house wiring, specifically the ground wire.
If you were to examine the TMCC signal on the common outer rail with an oscilloscope, would you see a flat signal? or an oscillating signal?
The 455 KHz carrier would be at a relatively constant level. The data encrypted on that carrier is probably FM, so you may or may not see slight frequency shifts.
I have no idea what you mean by "flat" or "oscillating" signals. Much of what you see will depend on the rep rate setting of the scope.
3RaylFan posted:Is the TMCC track signal bi-polar...
Yes, but a daily does of Lithium keeps the mood swings under control... 
gunrunnerjohn posted:There is only one signal element on the track, the other part is over the air from the earth ground.
This is saying a layout circle on a 4x8 sheet of plywood, in the middle of the woods, powered by a portable generator, will not function under TMCC. Forget about setting one up for an outdoor show ..... right? Anyone proven/dis-proven by actual trial?
Kerrigan, this is probably not true as you'd have the earth ground on the wire to the generator. It may be a weak signal, hard to say.
We often had trouble with the golden gate club layout when setting up in the Cow Palace, south of San Francisco. We figured that the ground wiring/connection in the hall was flaky.
