This is amazing frequency counter project. It’s construction is very simple but has a great use. High frequencies are more important for radio amateur who are dealing with radio transmitters and receivers. This frequency counter have ability to subtract the incoming frequency by offset(10.7MHz or 455kHz), so Intermediate Frequency of oscillator could be seen.
As this frequency counter is built under PIC16F870, it can’t measure high frequencies directly especially with high accuracy. Frequency is captured via frequency divider LMX2322 which divides by 64. Frequency counter has optional RS232 output what enables to output frequency value to PC screen or other devices. You can download all project files necessary from original page including two firmware versions 999MHz with 1kHz step and 2.5GHz with 10kHz step.