Batboard

We recently narrowbanded our VHF fire alerting system and purchased Minitor V alert receivers. In programming the new minitors, we noticed the squelch setting. When we set the squelch as 3 we noticed more noise etc when in the proximity of computers etc. At squelch level 5 much of that disappeared. My question is- does this squelch setting affect the alerting sensitivity? I recall in some radios we had and/or squech settings for PL and squelch. We would like to elinminate as much of the nuisance noise as possible without decreasing the alerting capability.