The prescaler described here connects to the front end of a 100-MHz frequency counter to extend ... (1.57-mm) double copper-sided printed-circuit board (PCB) that’s 7 by 2 in.

He’d like to have the 100 MHz version but the $400 difference in price puts it out of his reach. After some extensive poking around on the PCB and pouring over datasheets, he managed to reverse ...