Observing the travel of light
The falling edge of a single bit on a couple of cm long 115200 kbps UART connection between a 4D Systems OLED and a bluetooth module.
two more cables in between → longer signal propagation time: 3×108 ms-1 (4.2×10−9 s − 1×10−9 s) ~ 1 m
Resistive Z0 probe @ 100× built from old 10Base2 T adaptor, terminator, 3 m RG-58 cable and 4.7 KΩ metal film resistor
@ 50×, 1.5 m RG-58 cable and 1 KΩ carbon composition resistor
Bit-banging at maximum speed with a FT245R
Chromoflex 3 LED controller
Zooming and averaging reveal the 433 MHz ISM carrier