I have some info on ham radio on the PCT, including repeaters, at www.qsl.net/aa6j/pct . At the bottom click on California and scroll about half way down for the Whitney area.
Ham radio is another tool in the backpack. There's at least one ranger in Seki that carries one. Repeaters work great from passes, and do work at a few other places as well. I was surprised to learn there was a spot at Rae Lakes I could reach a repeater near Independence.
AsABat aka AA6J
(I don't get on this list.)
