[pct-l] advice about my hike

[Travis Polon]

Good Afternoon everyone,
   I'm a first timer so go easy on me! Ill be hitting the trail April 30;
NOBO from Campo to Crater lake!  So far my only question is will a cell
phone(AT&T) with half mile maps be a sufficient replacement of  carrying a
GPS?  How is cell service on the trail? will service be frequent enough to
keep the family updated a couple times a week?  Any and all feed back is
greatly appreciated!