I'm looking at the wiki and ANF site maps but can't figure out how many ANF service net sites there are. I had assumed they existed everywhere they had Forest and Admin net repeaters but that doesn't seem to be the case. TIA.
The Angeles, San Bernardino and Cleveland have shared a service net since the 1980's if I remember correctly from my time on some fires down there. Santiago Peak, on the northern ranger district of the Cleveland has been used by these three forests for quite some time. Region wide (USFS R5), concurrent with the frequency changes being made to bring radio systems in compliance with NTIA Redbook requirements, service net frequencies are not only being changed, but in some cases new repeaters are being installed. Some Forest net, admin net, National Flight Following and National Air Guard equipment is being replaced as well. The changes to the Angeles Service Net are scheduled for this "spring." Frequency changes for the admin net are also scheduled for this spring. I know it has already been summer in southern California, however I expect that in this case "spring" is April and May. Either that or it means "as soon as we can drive trucks with all our gear to the electronic sites we need to work on." The work could also be affected by equipment procurement/contractor schedules and any tweaking that has to be done in the shop prior to taking it to the site.
There is a plan of what sites will get new equipment and I expect that tones used for service net will match those already in use at the sites.
I don't have access to that plan, but maybe someone else here on Radio Reference does. In the meantime I would suggest monitoring the new ANF Service Net frequency of 171.5000 to listen to technician traffic. They tend to chat a lot while installing equipment and programming new frequencies at sites. When the regional frequency directory is published the tones for the new ANF Service Net will be included as I'm sure the plan is to have it working by the start of fire season or at least the part of it when large fires occur. The 2015 R5 frequency guide did not list service net repeaters for the Angeles, so we can't use it to determine where new service net repeaters may be installed or what their tones might be.
Technicians also test links, both UHF and microwave, during all of these changes so they might key up repeaters in other locations as well, using either the tone number or site name, e.g. "how does this sound on Lukens?" They might say "there is a little squeal on the Arcadia drop when I key up Tone 2" (Santiago). The radio conversations of techs during installation can be an opportunity to learn much of how a radio system works as they mention various links and their paths. The Angeles linking system is a bit complex as it uses one standalone microwave only remote control base, several microwave remote bases with an associated repeater, control repeaters and standalone repeaters. I have no idea how the old service net was linked.
I had thought that cell phones and satellite internet links would have replaced the service nets, This is not the case as it is obvious that new equipment, frequencies and sites are being added to it. Service net is primarily a Incident Command Post to local communications center link that handles logistical and resource ordering and status traffic. This type of traffic is best handled by phone and by computer using the "Resource Ordering and Status System" (ROSS) as then everyone is literally on the same page.
However, there are areas of National Forest land that have no cell coverage and likely never will. Satellite coverage is not a done deal at every location either. Large Type I and II incidents usually locate Incident Command Posts (ICP) at schools, regional parks and similar where phones and satellite have coverage. The greatest use of service net that I have observed has been on smaller, less complex Type III incidents that may set up an ICP at a fire station such as Rincon or in a campground. I've used it on Type IV incidents in some remote locations. Most of the use of service nets I observed was in the 1980's, prior to cell phone availability.
Service nets can also be used as an alternate command or field net during more routine incidents. On the Inyo there is a north forest net, a south forest net, a BLM net and service net. During major lightning busts the Mono Lake Ranger District might be put on the BLM net, the Mammoth RD will use north forest net, the White Mtn. RD remains on south forest net and the Mt. Whitney moves to service net.
Figuratively, you asked what time it is and I've explained how the watch is designed. The additional info might be useful to some people.