There have been other threads discussing the unit Id system at Yosemite. It is time for an update.
Mather I believe there are three ranger districts and the backcounty unit at this park. They would be Wawona, Valley, and
Mather. The backcountry unit may have been raised to a full on ranger district. The Mather District is apparently divided
into two subdistricts Tuolumne and Mather. I've only heard a limited number if employees using the Id "Mather," including
the District Ranger. Back in the 80's Mather had two subdistricts, Tuolumne and Big Oak Flat.
Tango Tuolumne Subdistrict
Mike Mather Subdistrict
Whiskey Wawona District
Victor Valley District
Traffic Traffic management and accident investigation. Not sure if every traffic employee is a commissioned LEO.
Hotel Valley horse patrol.
Bravo Backcountry law enforcement
Wilderness I believe these are unarmed backcountry management personnel
LYV Valley District personnel stationed in the Little Yosemite Valley. This is generally the first nights stop for people hiking the John Muir
trail from its start in the valley. A big wilderness management challenge. I heard "LYV 1" and "LYV 2", etc. while listening to the
Valley Net (166.300)
Sierra I thought this was Search and Rescue as Yosemite is one of the only National Parks that has a full time SAR organization.
I heard some Sierra units calling in service stating they would be on patrol. This may be Sierra units that take on patrol
tasks when not busy with SAR duties. "Sierra One" was heard when three simultaneous SAR incidents in the valley were being
worked. There is also a possibility that Sierra may refer to "Safety Management" also.
Rescue On the traffic accident incident I related above a licensed clinical nurse was heard using this Id on scene. I'm not sure
if she was a NPS employee or the employee of whoever runs the medical clinic in the valley.
Resource Almost all large units of the NPS are organized into four branches: Visitor and Resource Protection, Resource Management,
Interpretive Services, and Maintenance. I'm not sure if fire management is in Protection or Resource Management, but my bet would
be the latter. I heard several resource units go into service at all times of the day and they were likely to be bear management
people.
Ambulance Obvious. Ambulances appear to be numbered in accordance with the ranger district number series used by non-law enforcement
personnel. Mather = 2, Valley = 3, Wawona = 4, and park headquarters employees = 1.
Fire Management All use 500 series numbers.
Backcountry Unit or District Use a 600 number series.
Trail Crews Use the 620 series
There are no 700 units as those were reserved for fixed stations but now those stations use geographical Id's such a "Tioga Pass" and "South Entrance."
Research Scientists and Techs use the 800 number series.
In the numbered series 50's refers to buildings/grounds maintenance or campground maintenance. 60's refer to roads maintenance and 70's to water and sewer maintenance or electrical maintenance. Plumbers use the 80's number series. Example "381" is a Valley District plumber, "262" works Mather District roads, and 672 maintains backcountry buildings such as ranger stations.
Now that leaves some other protection Id's. I heard "Delta" units going in service between 0600 and 0900. I suspect these would be Valley Ranger District day shift LEO's. I listened carefully for "Echo" units, which I would guess to be evening shift protection rangers. I've heard this call sign on previous trips. I haven't heard the graveyard or night shift units, which I would guess to be either "Golf" or "November" Id's. In the 80's the Valley Ranger District had an El Portal subdistrict and Echo could reflect this, but several years ago I picked up a rumor that the number of subdistricts was being reduced with El Portal being on the top of the list. The Valley Ranger District is one of the only non-urban National Parks where there is a regularly scheduled graveyard shift. Others are probably Grand Canyon, Yellowstone, and Great Smokey Mountains due to high visitation. There may be more.
I need to spend some time in Yosemite Valley in order to confirm these Id's as applying to Valley Ranger District shifts. I need to be in range of the Turtleback repeater on both the Valley Net and Law Enforcement Net. As a private citizen I've only stayed two nights in the Valley in my life and both were at Camp Curry. The social scene for my wife and I with some friends prevented much listening. As a federal employee I've spent 15-20 days in the valley, but there was even less time to monitor as I was in meetings and "networking" in the evenings. These trips were all during the week in the fall or winter, when the radio traffic in the park is pretty low. The radio system has gone through extensive changes since then anyway. A good spot for hearing most of the park's repeaters is at Olmsted Point, with the best being on Sentinel Dome, where the park's remote base stations are likely located.
As for the frequency of the Law Enforcement net, I'm sorry but I can't share that.
The alphanumeric system of Id's for protection rangers (mostly) is being used in other parks as well. Grand Canyon comes to mind. Death Valley is still using three numbered series such as 100, 200, etc.
I welcome hearing from anyone who has observations of the above.
