Addintional
I forgot to mention that the channel plan in the official directory of 2014 was the first time I saw the 3 frequency backcountry net. Many National Parks have installed systems where every repeater has a different output frequency and a common input. This allows everyone, park wide, to hear all the traffic on the net. Obviously, a voter is employed and the operation is seamless for the operator of the mobiles and handhelds. We are likely to see more of this.
Sequoia-Kings Canyon's frontcountry net is set up this way. There are 6 repeaters with 3 frequency pairs. Repeaters sharing a pair are located with both distance and topography separating them. Each repeater is then accessed by a CTCSS tone. The Kings Canyon backcountry repeaters are accessed by Tone 6, 156.7. The Sequoia backcountry repeaters are accessed by Tone 7, 167.9.
If these repeaters are linked UHF frequencies would have to be used as microwave could not be used due to the remoteness and topography of the repeater sites. The system would have to be linked with UHF frequencies that would all tie back to the hub of the Sequoia Kings Canyon radio system at Parkridge. We know that Parkridge is capable of hearing each repeater in order to allow dispatch at Ash Mountain to work each repeater. There wouldn't be a voter as each repeater pair has a different input frequency.
More than one repeater can be heard from many of the highest locations in the park. In the 70's repeaters were accessed and interference reduced by having two different input frequencies. The new tones reflect these two different input frequencies of the past. I don't recall when this two input frequency system was replaced, but it hasn't been that long, perhaps in the 90's or early 2000's. One of my subordinates on a National Forest north of Sequoia-Kings had been a backcountry ranger at that park in the 70's. He told me that in some areas keying up one of the channels, each with separate repeater input frequencies transmitting, would bring up more than one repeater. The possibility of doing so has been reduced by increasing the number of frequency pairs to 3 and then further splitting those into two different repeater access tones.
Having a linked system on the backcountry net, just like the frontcountry net, is very important. Hearing the traffic of a ranger in the Evolution Valley is essential for a ranger at the Rock Creek ranger station as an alert to contact a party might pertinent to the south end rangers on the Pacific Crest Trail. There also might be traffic called in by the ranger in Evolution Valley in relation to a group of belligerent, non cooperative and non compliant group and should they stay on the Pacific Crest Trail it is important for the ranger working from the Rock Creek ranger station to hear the other rangers conversation. The alternative is to have the dispatcher repeat the traffic on all the other repeaters, something that takes a lot of time and is summary of what one ranger has said. Quite often hearing the inflection in a ranger's voice speaks volumes.