@SteveH posted:Please forgive my unfamiliarity with the DCS system. John, between which devices is the DCS signal strength measured and then displayed on the remote?
The "signal strength" measurement is really a misnomer. What is actually being checked is sending packets to the locomotive from the TIU and then counting the returned responses. If you are reading 10's, that means all packets are being responded to and received by the TIU back from the locomotive. However, that doesn't actually measure the signal strength on the track, it is really just checking if there's enough signal for packets to go back and forth.
@rplst8 posted:
As I understand it, in the TMCC/Legacy world the track acts as an antenna. How much track do you have? If it was a length of 1000 feet (1/2 wavelength) or multiple thereof, the signal can reflect and "resonate". Based on your earlier post it sounds like it's doubtful you have that much track.That said, RF is a tricky business I wouldn't rule out a particular combination of length, materials, and shape to making a more effective antenna out of the track. However, characterizing that benefit/degradation would require someone with a lot of RF knowledge and likely some RF modeling tools.
Actually, the track is NOT an antenna in the world of TMCC. The "antenna" inside the TMCC locomotive is picking up the radiated signal from the earth ground (3rd prong of house wiring), the track side of the signal is connected through the wheels to the electronics directly. In this regard, the RF propagation model is kind of upside down, but the effect is still the same.
Dale Manquen wrote a significant piece on TMCC Signal Basics, and he clearly explained it much better than I will. Sadly, his website is no longer up, but I captured that topic here.
Dale's TMCC Signal Basics.pdf
Dale's description is spot on.
@rplst8 posted:
My guess is that the processor doing the signal extraction (Adrian mentioned it was some sort of convolution, which to me says it's a DSP of some sort) is not as powerful in the PS2 engines as in the PS3 engines - which makes sense. Typically in that world, if you increase the size of the Fourier transform used you can pull more signal out of the noise at the expense of integration time, i.e. the result might take longer to get. However if the DSP is faster, you might get it for free in PS3 chipsets.
I believe when Barry was around he stated that exact same thing. I know both the Rev. L and PS/3 chipsets got a much more powerful DSP signal processor for better performance.
