This a low cost portable 1.6 GHz counter using a PIC counter based on IK3OIL design. For 2*16 LCD you can use these files for HEX code. I use a MB506 prescaler to have 2.4 GHz capability (I see that on the PDF it says that it can measure up to 1.5 GHz - I measure that it goes up to 1.677.7 GHz -this it must be because it use 3 byte for frequency). Software permits to use any prescaler with 10,128,64,32 division. With MB506 you can safe use 64 division as it can measure 37.5 MHz. Do not forget a 2.2K  from MB506 output to GND. For the low input I use the circuit from 1982 ARRL handbook found on 16-14 page with the MPF102 & 2N3563 (I use equivalent ones). You can of course use any similar circuit. I use power from 230V or external 12-13-8V source. For the prescaler and the low input circuit I use the ugly method (without PCB).  To adjust the frequency I use a 5-30 pF variable capacitor on the back side of the PCB instead of one of the XTAL.