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Reply to "TMCC/Legacy Track Signal Booster (Dale's Legacy Continues)"

gunrunnerjohn posted:

One thing I might suggest it to "tone down" the buffer output somewhat, while still keeping a lot of the benefit of it being used.  Here's a simple way to "tune" the buffer output, see if this helps.  I'd start with my suggested values, this returns the amplitude of the TMCC signal to near default, but still allows you to have a lower impedance signal to help drive the TMCC problem areas.  You can then maybe change the resistors to 150 ohms each to give a small boost if the first one doesn't do enough for the TMCC.  The resistors should be 1/2 watt or larger.

TMCC Booster Voltage Divider

Adrian was talking about this, and I figured it would depend on exactly how the DCS was wired.  I suspect a perfectly optimum wiring of the DCS might not have the issue, but if you have any signal degradation of the DCS signal, it may be more adversely affected by the boosted TMCC signal.  Note that just because you got 10's for the signal test, that doesn't mean you have perfect DCS signal, it just means you have enough for solid communication with the locomotive.

Last time I was in civilization we had a good 10-12V DCS swing everywhere on the layout, but we were somewhere around 1/3 to 2/3 capacitive imbalance inner to outer rails meaning the 450KHz will show up across the DCS differential voltage at 1/3 of the amplitude it has to Earth ground.  I may try to hack the driver stage on your buffer to drop the voltage gain while maintaining the low output impedance.  

We had an accident on the launch line so we're being encouraged to scrub. I may be back working on this buffer sooner rather than later. 

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