Los Angeles County

[rananthony04]

[QUOTE="Radio_lady" The "beep" tone is used, as has been noted previously, by the dispatcher to indicate that A: there is a unit transmitting on one of the input channels the dispatcher has up on the console ( often up to 3 or more different station districts at the same time) and therefore ALL other units must not transmit unless it's emergent....). B: The dispatcher is busy with something (running a plate, telephone to a station desk, etc) and is not listening critically at that moment. C: the "busy" tone can be activated to come on automatically whenever there is a unit transmitting on an input channel."[/i]

ESPECIALLY since they don't run repeaters normally, the dispatcher is the only person on earth at the other end of a deputy's radio, should he/she need help right now. If the dispatcher isn't "listening critically," the deputy's one and only chance to call for help could be missed while the dispatcher's on the phone and letting the "busy" beep tell them that "now's not the time to bother me." I really have to hope he didn't mean that the way it looks.[/color][/QUOTE]

The beep tone is only accurate in choice "A" and "C" as stated above. No other reason causes the busy tone other than a deputy talking to dispatch. We scanner enthusiast's only hear the dispatcher.(not even other deputy's can hear each other) When a deputy requests the patch, dispatch lifts the busy tone to allow the deputy to relay info, or coordinate something. Once done, the patch is released and responding deputy's switch over to a tac channel.

 

[scankid2591]

Are there any other agencies in L.A. County that use (somewhat) the same kind of system (analog but "busy tone" when trying to listen to mobiles)?

 

[Radio_Lady]

Are there any other agencies in L.A. County that use (somewhat) the same kind of system (analog but "busy tone" when trying to listen to mobiles)?

I've never heard of any other agencies ANYWHERE that do it. I've heard of some that would turn off the repeat function on occasion when asked to do so for security or privacy reasons, but that's almost never.

Before going to UHF, LAPD was on semi-duplex with no repeaters, but we had to be... each talk-out freq was shared by from three to six dispatchers, and it would have meant from three to six mobile freqs on the uplink simultaneously.

Oh, I didn't really understand what you meant by "an undecoded transmission from a P25 radio sounds like that "busy" or "beep" tone that LASD uses..." LAPD's undecoded P25 sounds like static/hash when it's being transmitted. It has squeaks and squeals, but I've never thought it sounds like LASD's busy-beep.

 

[scankid2591]

Oh, I didn't really understand what you meant by "an undecoded transmission from a P25 radio sounds like that "busy" or "beep" tone that LASD uses..." LAPD's undecoded P25 sounds like static/hash when it's being transmitted. It has squeaks and squeals, but I've never thought it sounds like LASD's busy-beep.

I thought it kinda sounded like it the last time I was down in Los Angeles.

I had a load of fun scanning even though I barely got Ventura County (to SLO County) programmed in at the last minute.

I remember hearing a fire dispatch somewhere in the 800 or 900 MHz range when I was down there. I heard the tone, the dispatcher, then the units. Then it just when to some kind of sound like I turned down the squelch to 0. Maybe I didn't have my squelch up very high.

 

[Radio_Lady]

I remember hearing a fire dispatch somewhere in the 800 or 900 MHz range when I was down there. I heard the tone, the dispatcher, then the units. Then it just when to some kind of sound like I turned down the squelch to 0. Maybe I didn't have my squelch up very high.

L.A. City Fire is on 800 MHz, but strictly analog and conventional, no digital or trunking. Somewhat like LAPD, many of their dispatches are "silent," sent only by wireline and data feed. Only when some of the assigned units are out of quarters will the "dispatch" itself go over voice radio, otherwise only a brief narrative will usually be voiced after the dispatched units are on their way. Many of the follow-up messages, size-ups, etc will of course be voiced.

 

[scankid2591]

Hey... alright. That's all the frequencies for the entire city of L.A.'s Fire Dept.? Wow... that's pretty small.

 

[rananthony04]

Hey, LA City Fire gets the job done! Also, don't forget about LA County fire as well, they are also conventional and use the 470 part of the frequency spectrum. Alot of tacs used by LA County Fire utilize the 150 - 159 part of the freq spectrum.

 

[rpoole23]

Being new to the west coast, and new to working for a Califonrnia agency, that LASD radio system sounds a little to "unsafe" to me. Do they have laptops or MDC's or any other in car computers to communicate with anyone? Still seems strange to me to not be able to hear what my fellow officer is saying. I have a lot of respect for dispatchers but every now and then you run into one that is just "not very good" and it becomes necessary to hear what the other officers are saying out on the street...

 

[hotdjdave]

Are there any other agencies in L.A. County that use (somewhat) the same kind of system (analog but "busy tone" when trying to listen to mobiles)?

CHP uses a mobile/base pair frequency configuration. To hear the CHP Traffic Officer, you must tune into the mobile freq and be within range.

 

[KMA367]

CHP uses a mobile/base pair frequency configuration. To hear the CHP Traffic Officer, you must tune into the base freq and be within range.

In many parts of the state outside of the L.A. area, CHP has gone to repeaters, or more correctly "mobile relays" so you can often hear the cars on the base freq. I believe most of the Inland & Border division patrol areas use them, as do Chico and Humboldt. I don't know about the Sacto & San Joaquin Valleys. Depending on the geography of some of their huge patrol areas, it's not always best for them to have the repeat function enabled.

But otherwise, as you suggest, it can be really tough to pick up CHP mobiles on a scanner if you're not in the right spot with the right antenna and a sensitive enough scanner.

 

[scankid2591]

CHP uses a mobile/base pair frequency configuration. To hear the CHP Traffic Officer, you must tune into the base freq and be within range.

You mean to hear the CHP Traffic Officer, tune to the Mobile freq, right?

It's not even worth tuning into the mobile channel in Monterey County. I can't hear a danged thing, but on the mobile repeaters however, I can hear full mobile radio traffic. Sometimes they'll use the Mobile Extenders frequency but that's usually pretty scratchy.

 

[hotdjdave]

You mean to hear the CHP Traffic Officer, tune to the Mobile freq, right?

You're right, my mistake...I meant mobile. Correction made. Thank you.

 

[rananthony04]

Dave is correct in regards to having to tune to the CHP mobile freq to hear the CHP officer. I know that my Baldwin Park office does not allow listeners to hear both on one channel, I have to manually tune to mobile if I want to hear the officer talk, and I would have to be in a good area or be super close to have a clear signal. Altadena for instance allows listeners to hear both dispatch and mobile on one channel, same with all of Orange Co.
-Robert

 

[code6]

CHP simalcast

I have heard southern division CHP offices being simalcast, usualy Altadena and
Baldwin Park and sometimes East LA and Santa Fe Springs. With the use of
2 scanners being programmed with the base frequecies one is able to hear
both sides of the transmissions being simalcast.

 

[scankid2591]

Funny...

Today I heard a Mobile on the Base freq...

 

[hotdjdave]

In a large metropolitan area like Los Angeles, there is usually a CHP unit within a few miles of you wherever you are in LA (especially if you are on a freeway or live near one - I live about 2 miles from the 101, about 3 miles from the 405, and about 8 miles from the 118 - most people in LA live within a few miles of at least one or two freeways). This makes it easier to pick up the Mobile transmissions.

 

[scankid2591]

Hmm... You have it easy.

Yep, I live near highways (300 yards from Hwy. 68, 3 miles from 101)...

BUT the only problem is, 101 runs thru the northernmost tip of Monterey County thru the southernmost tip. That's about 80 miles.

 

[rananthony04]

I live about 1 mile from the Baldwin Park office and I still cannot hear mobile units on base freq or even the mobile freq. I literally have to be in view of the unit to successfully and clearly hear the mobiles.

Robert
Baldwin Park

 

[scankid2591]

Hmm... I wonder if they have Mobile Repeaters in SoCal.

 

[Radio_Lady]

CHP mobile relays in SoCal

Hmm... I wonder if they have Mobile Repeaters in SoCal.

They do. in some areas on some frequencies.

Tracy's website is a very good frequency resources for Southern California especially, and you can see the CHP info at http://freqofnature.com/index.php?m=California&p=Cal Highway Patrol

At the bottom of the page is a chart of the frequencies/offices, and there's an antenna icon at the far right of the rows for those that have repeater capability. Keep in mind, though, that the repeat function is not always enabled, and not every mobile transmission is repeated from every transmit site. That would cause havoc (and officer safety issues) over the huge areas that many of CHP's dispatch centers cover.

It's not totally up-to-date, but it's close. I believe the Orange County Comm Center's frequencies have repeat capability.

Someone mentioned earlier that "Altadena for instance allows listeners to hear both dispatch and mobile on one channel". I'm sure everyone on here understands that the mobile relay function isn't there for general "listeners," but rather for the dispatchers and officers. We just get the benefit