RivCo Fire Question

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cvrules90
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Joined: Tue Feb 22, 2011 8:08 am

RivCo Fire Question

Post by cvrules90 »

Is it possible to receive the west end of the county from the east (e.g. desert area) and vice versa? I once got 151.385 very stratchy and staticy from Palm Desert.
zz0468
Posts: 236
Joined: Wed Jun 18, 2008 8:35 pm

Re: RivCo Fire Question

Post by zz0468 »

Not very good, as you have already noticed. There are a number of transmitter sites used, all with their specific coverage areas. There really aren't any sites in use that would cover decently in both the desert, and the west county. Mt. David in Beaumont might be heard in some parts of the desert, and Whitewater might be heard in a few places out west, and occasional propagation enhancements might cause something to be heard where it's not normally. Otherwise, those 11,000 foot mountains on each side of the pass are a pretty effective shield.
cvrules90
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Joined: Tue Feb 22, 2011 8:08 am

Re: RivCo Fire Question

Post by cvrules90 »

So that's probably why the online feed only broadcasts the west county. I believe it's quite the same for the RSO EDACS system in that you can only hear the site(s) you are most close to. In the desert, you only really get the desert stations and maybe another station if you happen to get lucky (I"ve been known to hear Cabazon cars in the desert on the Desert System).
zz0468
Posts: 236
Joined: Wed Jun 18, 2008 8:35 pm

Re: RivCo Fire Question

Post by zz0468 »

You should probably find some sort of on-line tutorial on how radio systems work. There seems to be some elementary things you don't quite understand.

Starting with some absolute basics, Riverside County (Fire, RSO, etc.) has a large number of transmitter sites. All you'll be able to hear is the transmitter sites that can get usable signals to wherever your receiver is. If a transmitter at "Site A" just doesn't get any signal to your receiver at "Site B", you won't hear anything. It's blocked by mountains and hills, mostly. Add to that the need for them to divide traffic load into regions so dispatchers are only working calls in a specific area. The end result for you is, if a dispatcher is working, say, the Lake Elsinore area, those calls will go through transmitter sites that serve the Lake Elsinore area. You won't hear much in the desert for those calls.

There are some county wide talk groups on the 800 system, and on the fire VHF systems they can multi or simul-select transmitters and make it county wide, but that's an operational task that I don't necessarily have details on. Also, the EDACS system can send a call to a different cell if a mobile unit needs it to, which is why sometimes desert traffic is heard on the Central system, and vise versa.

If the on-line feeds are only providing west county traffic, that's likely because the receivers generating those feeds are not in a location to receive signals from transmitters located in the desert. You'd have to have receivers physically located in the desert areas in order to hear those transmitters.

And as a further note, in some cases, specific transmitters are tailored to provide coverage to a specific area, and not much further. This can be especially true for simulcast systems. Another note, on the EDACS system, with one exception, there are no transmitter sites located at actual sheriff stations. It's all up on mountain tops, so proximity to an RSO station will do you little good.
cvrules90
Posts: 1393
Joined: Tue Feb 22, 2011 8:08 am

Re: RivCo Fire Question

Post by cvrules90 »

zz0468 wrote:You should probably find some sort of on-line tutorial on how radio systems work. There seems to be some elementary things you don't quite understand.

Starting with some absolute basics, Riverside County (Fire, RSO, etc.) has a large number of transmitter sites. All you'll be able to hear is the transmitter sites that can get usable signals to wherever your receiver is. If a transmitter at "Site A" just doesn't get any signal to your receiver at "Site B", you won't hear anything. It's blocked by mountains and hills, mostly. Add to that the need for them to divide traffic load into regions so dispatchers are only working calls in a specific area. The end result for you is, if a dispatcher is working, say, the Lake Elsinore area, those calls will go through transmitter sites that serve the Lake Elsinore area. You won't hear much in the desert for those calls.

There are some county wide talk groups on the 800 system, and on the fire VHF systems they can multi or simul-select transmitters and make it county wide, but that's an operational task that I don't necessarily have details on. Also, the EDACS system can send a call to a different cell if a mobile unit needs it to, which is why sometimes desert traffic is heard on the Central system, and vise versa.

If the on-line feeds are only providing west county traffic, that's likely because the receivers generating those feeds are not in a location to receive signals from transmitters located in the desert. You'd have to have receivers physically located in the desert areas in order to hear those transmitters.

And as a further note, in some cases, specific transmitters are tailored to provide coverage to a specific area, and not much further. This can be especially true for simulcast systems. Another note, on the EDACS system, with one exception, there are no transmitter sites located at actual sheriff stations. It's all up on mountain tops, so proximity to an RSO station will do you little good.
I actually knew a lot of this. Maybe that's why RSO has 3 dispatch centers.
zz0468
Posts: 236
Joined: Wed Jun 18, 2008 8:35 pm

Re: RivCo Fire Question

Post by zz0468 »

cvrules90 wrote:I actually knew a lot of this.
Then I have to wonder what it is you're really asking.
cvrules90 wrote:Maybe that's why RSO has 3 dispatch centers.
Logistics. They did it all with one, and then two, dispatch centers for a lot of years. Separating the geographical areas for calls doesn't require separate dispatch centers.
cvrules90
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Joined: Tue Feb 22, 2011 8:08 am

Re: RivCo Fire Question

Post by cvrules90 »

Well if Fire and EMS is limited to sections of the county, how can a crews in a truck talk to Perris from Palm Desert?
Last edited by cvrules90 on Sun Apr 21, 2013 4:17 pm, edited 1 time in total.
zz0468
Posts: 236
Joined: Wed Jun 18, 2008 8:35 pm

Re: RivCo Fire Question

Post by zz0468 »

They're not limited. You, as a scanner listener, are limited.

The radio system is at multiple sites intended to serve specific areas. Between the bunch of them, pretty much the whole county is covered. Those radios at all those sites are brought back to Perris on microwave links, etc. So, Perris can listen to a base station in Palm Desert (or Blythe), and talk to that truck out there. You, as a scanner listener, listening to a feed with a receiver located in Riverside won't hear that conversation, even though Perris and the truck in Palm Desert communicate with each other just fine. You could be sitting parked across the street from the Perris command center, and you still won't hear that conversation with that Palm Desert truck because the transmitter Perris is talking to the truck over isn't located there. Their radios are all controlled remotely.

Make sense yet?
cvrules90
Posts: 1393
Joined: Tue Feb 22, 2011 8:08 am

Re: RivCo Fire Question

Post by cvrules90 »

Actually, it looks a lot like what Washington State Police has here.

They've got an interconnected VHF radio system which reuses the same frequencies in the state. On the dispatch channel, you can hear dispatch clearly, but the troopers usually can barely (if at all) be heard. You also are only restricted to the specific part of the state. I live in Seattle where state patrol dispatch on 155.58 which is also the frequency for Spokane dispatch. I can't hear anything in Spokane from here even tough it's the same frequency.

The sites (I'm not too sure about this) are placed just on the grassway off the freeways where the troopers drive. Therefore, I believe they are remotely controlled so I get the communications officer loud and clear, but am lucky if I ever get to hear a trooper talk.

And they've added P-25 recently like LAPD does.

So, if I now understand, Riverside County Fire radio sites are remote-controlled and the same frequencies are used in the entire county, but becuase the sites are remote-controlled, and the dispatcher, I would think, selects the site from the computer that's closest to the piece of apparatus they wanna talk, I wouldn't be able to hear the Palm Desert truck from Perris and vice-versa.
zz0468
Posts: 236
Joined: Wed Jun 18, 2008 8:35 pm

Re: RivCo Fire Question

Post by zz0468 »

cvrules90 wrote:The sites (I'm not too sure about this) are placed just on the grassway off the freeways where the troopers drive.
I would doubt that's the location of most of their transmitters. They probably need communications off the freeways as well, so the base stations are probably located on mountain top sites. Maybe a few near freeways for fill. That's between God, the accountants, and the radio engineers.
cvrules90 wrote:Therefore, I believe they are remotely controlled so I get the communications officer loud and clear, but am lucky if I ever get to hear a trooper talk.
They are most certainly remotely controlled. That's how it's done on large systems.

If you don't hear mobile traffic, then they must be relying on simplex. Nothing wrong with that if it works for them.
cvrules90 wrote:So, if I now understand, Riverside County Fire radio sites are remote-controlled and the same frequencies are used in the entire county...
Not necessarily the same frequency. There are good reasons to use the same frequency at multiple sites, but that adds a level of complication. A look at an accurate frequency list, and careful listening, can reveal a lot about how a system is constructed.
cvrules90 wrote:but becuase the sites are remote-controlled, and the dispatcher, I would think, selects the site from the computer that's closest to the piece of apparatus they wanna talk, I wouldn't be able to hear the Palm Desert truck from Perris and vice-versa.
Um... the "computer" is probably in wetware (the dispatcher's brain), and they know what radio to use to talk to what area. They may not know what mountain top "Support Net 3" is on, fior example, but they know that's the one to use to work with a certain set of stations. That information *could* be stored in CAD, and pop up when they tone out a station, I don't know for sure. But the actual selection is manual at the radio console. They also have the ability to select multiple sites and transmit and hear over several of them with one button push.
Last edited by zz0468 on Mon Apr 01, 2013 10:20 pm, edited 2 times in total.
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