[Dr_C]

I guess I have the luxury of designing a brand new 36 car digital system in 2024 without any constraints from legacy commitments. This is a nice starting position :)

First, like many of the current digital slot car  solution providers I have started with the Nordic chipset which implies the Nordic ESB (enhanced shockburst) protocol. And nice it is too.

Nordic offer three data rates and, like many I would prima facia presume the highest data rate is best. But is that the case?

The data rates for Nordic devices are 250kbits/s, 1Mbits/s and 2Mbit/s. 

And it should be noted the 250kbit/s rate is currently being phased out.

In the early days, 250kbit/s was optical because it offered best signal-to-noise hence best range. However with time Nordic have improved the range performance of the 1Mbit/s option. This is now ideal, in my opinion, for current and upcoming digital slot car systems.

The 2Mbit/s option is attractive because it adds double the data rate but there is an important compatibility challenge in that consecutive frequency channels cannot be used due to the signal bandwidth speading across these adjacent channels. This means twice the bandwidth but half the number of available frequency  channels. So for system designers who wish to use adjacent channels this appears to represent zero sum gain.

In my system design I am using 1Mbps bandwidth so that all Nordic channels can be used separately and effectively, including for frequency hopping methods.

I believe this is in line with the prevailing wisdom across digital slot car system developers i.e. 1Mbit/s is optimal and 2Mbit/s is to be avoided.

Enough theory, next let’s see digital slot cars running at track level… i.e. theory into practice :)

c