San Bernadino - why multiple systems?

The shootings this week and the focus the San Bernadino County's radio system has had as a result reminded me of something I always wondered when seeing that the county has ten separate trunk systems. That question is: Why??

I understand it's quite a large county by many standards, but there are plenty of comparably-sized places across the continent that have a single system covering the whole area.

When the systems were first being built out, was there a technological hurdle that required them to create ten separate systems with ten system cores and so on?

From the looks of the talkgroups listed in the database, it doesn't seem like there are more than 4095 talkgroups (the theoretical limit of one Mot type II system) and that would presumably mean less than 65535 radios as well.

Did OmniLink not exist when this (group of) system(s) was being designed? IIRC even 3.x OmniLink could have handled up to 96 individual tower sites across 3 system IDs.

Or is (was) it unrealistic to link tower sites, i.e. through mountainous terrain, inhospitable conditions, etc?

It just seems like ten individual Smartnet systems would cost a lot more than one Smartzone system.

Hopefully someone else can fill in the details (and correct any mistakes), but the easy answer is SmartZone didn't exist when San Bernardino County made the switch from VHF highband to 800 MHz in the mid to late 90s. These systems were state of the art when put into service and something like this had never been done before. I remember hearing about agencies coming from around the world to see how this system worked.

I worked for SBSO when the trunked system was implemented, and was 'boots on the ground' during the migration from VHF to 800. IIRC from my conversations with Dave Seidel, the SO's 800 system maestro, LBH is correct. SBCo's new radio system was the first of its kind in size and scope

This was a new concept for a system of this size (remember SBCo is the largest county in the lower 48). Part of it was also the County's Ops plan: On VHF, each outlying sheriff's station had its own dispatch. With the migration to 800, the SO consolidated into 3 centers, Valley, Desert, and Needles. There was serious discussion about consolidating all into one center either at Rialto (Valley Com shares a facility with Comm Center, the county fire dispatch) or a new center in the Victor Valley. For multiple reasons including politics this didn't happen. The original System breakdown followed geographic lines, and each Center handled systems related to its geo area. The original design only consisted of Systems 1-8 plus conventional repeaters in the remote nooks and crannies of the county the trunked system couldn't reach. System 1 used to only cover the Victor Valley, and System 2 was for Barstow; System 1 has been converted in the last few years sometime to a wide-area system and covers both. Systems 9-15 (or whatever they are up to now) are relatively new (in the full life cycle) to the system as add-on for SBPD and other agencies (System 10), and as overlays to the original systems.

Someone with more technical knowledge than i will have to explain why they did the overlay systems (e.g. System 14 overlays the geo footprint of System 4).

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Thanks both of you, that makes sense now.

That explains why they were able to keep keying up on top of each other all day too now. Wait scratch that - they're Analog. Doesn't the control channel prohibit two radios keying up at the same time?

It should have. When I was there, as long as you were on the trunked part of the system, transmit inhibit kept you from talking on an occupied talk group.

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Apparently tx inhibit is no longer enabled. It REALLY irritates me on the fireground when EVERYONE has a speaker mic and "almost" everyone doesn't know how to wear them so they don't get keyed. Sounds a lot like what we all heard on the SBPD 10-system on Wed.

The single-radio keyed mode is an option in SmartNet/SmartZone systems. While most systems of the era operate in the single-radio keyed mode, some like the San Diego City system (and, apparently SBDO) allow multiple users to key up.

AFAIK, it is not an option in P25 systems.

K6CDO said:

The single-radio keyed mode is an option in SmartNet/SmartZone systems. While most systems of the era operate in the single-radio keyed mode, some like the San Diego City system (and, apparently SBDO) allow multiple users to key up.

AFAIK, it is not an option in P25 systems.

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San Diego City system is the first thing that came to mind for me as well. It was funny coming from MERA with single-radio keyed mode and going down to San Diego and hearing:

"Wwwwwrrrrraaaaawwww"
"Multiple units, 811 John go ahead?"

The DTMF ET tone was pretty unique too. Sad that thing went away with the P25 core upgrade.

inigo88 said:

The DTMF ET tone was pretty unique too. Sad that thing went away with the P25 core upgrade.

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I've got a good recording of that DTMF ringer' tone. I'll post it up.

Here is a recording of the old SDPD emergency traffic tone
SDPD ET Tone

Here are other PD and fire tones you can listen
https://www.dropbox.com/sh/oirvos4hpwi6dlg/AAD88cd8UFDeY8IKnZi8nKFwa/audio/tones?dl=0

Awesome! Thanks for the link, Brandon.

I have that ringer as a zone tone on my APX:

https://youtu.be/8TebRx1DALc


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I realize that this is an older post but one answer seems to be missing. I don't recall the date that it switched maybe Don does. But FCC regulations require that new systems be built utilizing a cell phone type infrastructure as far as towers and range so as to allow frequency reuse. It is not uncommon to hear San Bernardino PD in Pursuit and then terminating because they know exactly where they're going to lose radio coverage. If 40-King is not over him already or CHP ready for the handoff they 10-22 the pursuit. This is just one example. When it comes to fire as they almost all switch to VHF fireground if the fire is substantial size and requires a second alarm or better where CALFIRE or Forest Service may come in. This applies to all cities adjoining and urban interface including Chino Hills or the Anaheim Hills where several years ago we had the Triangle Fire (Complex.)

Can you rephrase the question? Are you asking for a date?

Maybe somebody can confirm but I recall reading on forums here that freqs in the 860 range were to have a local footprint and those in the 850-859 could have a larger footprint and were best for regional simulcasting?