Most radios are configured for tone squelch when mike is on hook and fixed squelch from control inside radio when mike is off hook.
To use external squelch see below.
Receiver 11.2 If low side injection . operating frequency minus 11.2 divided by 3 equals xtal frequency
52.525-11.2 / 3= 13.775
This is important you must state low side injection with 11.2 IF
52 MC. radio dose not normally have 11.2 IF
Transmitter operating frequency divided by 3
52.525 / 3 = 17.508333