This is my frequency counter. I have put it into case of my broken Zetagi amplifier ( it's not all bad as it seems, HI).

PCB is 58mmx50mm, but it can be smaller.

Frequency meter measures up to 50MHz and if you add a prescaler, it measures up to 1.3GHz.

front*	PCB in amplifier
PCB in amplifier	back - HF/UHF measurement connectors

* still not finished - there's missing button for HF/UHF measurement and to put LED display into the box