This project seems to be at the point where I could tack on a Z8 and call it done. I may hook up the Z chip as proof-of-concept for the input section, but the goal is still the Turing machine decoder. All that is needed to build to this stage is a bunch of passives, a transistor, a quad op-amp, and a comparator.

Here is what is on the proto-board at the moment:

The circuit starts with a quick and dirty 2.5-ish volt tap that becomes the op-amp ground reference. Next up is a fairly basic transistor amplifier. Most any general purpose transistor will work for 60kHz WWVB signal. Now the hard part, two sections of the op-amp form a 60kHz filter with a lot of gain. I have to  thank Analog's Filter Wizard for taking care of the heavy lifting. The nice looking sinewave at the output of the filter is fed to a precision full-wave rectifier and output filter capacitor, like it is a DC power supply. That DC voltage causes the comparator to switch the LED on and off as the WWVB carrier changes.

Well, why not? I'm going to hunt down a dev-board...