In the February, 1994 edition of QST magazine, William Alsup, N6XMW from Oakland, CA, wrote an article proposing a Wilderness Protocol "for effective simplex use of handheld VHF and FM transceivers in the backcountry." In the August, 1995 QST, William reported enthusiastic support of the proposal and reminded us to spread the use of the protocol.
OST Features editor Brian Battles, WS1O, added a note, "Remember, though, this protocol won't work if it's only used by hams who need to call for help - someone else has to be listening." William's original proposal was only for 2-meter use, but Brian's note urged us to, "Check the national calling frequencies on all bands for which you're equipped, and give your call sign once or twice so that others will know you're there."
"The Wilderness protocol (see page 101, August 1995 QST) calls for hams in the wilderness to announce their presence on, and to monitor, the national calling frequencies for five minutes beginning at the top of the hour, every three hours from 7 AM to 7 PM while in the back country. A ham in a remote location may be able to relay emergency information through another wilderness ham who has better access to a repeater. National calling frequencies: 52.525, 146.52, 223.50, 446.00, 1294.50 MHz."