Confused about LASD radio systems

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drsn0w

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Hello RadioReference!
I'm using an RTL dongle to listen to LASD frequencies in my area, and I'm confused about a few things.

1. I understand the busy tone, but why is it sometimes a steady pulse of beeps and other times it sounds like morse code?
2. With SDR# I get a waterfall view of about 2MHz of spectrum, and I often see the same audio being transmitted on 2 or 3 different frequencies, or I'll hear dispatch audio for areas nowhere near me on my dispatch channel (aka. hearing audio for Venice on Temple dispatch).
3. I keep hearing "415 family on _____". What does that mean?
4. Lastly, how come I'm picking up some LASD audio on frequencies not listed on RadioReference?

Thank you!
drsn0w
 

Ghstwolf62

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To answer a couple of questions for you.

The set up in dispatch from what I understand is that traffic is routed to any open dispatcher to handle and because of that dispatchers can end up with multiple areas on their console at the same time. They usually drop all other areas if 10-33 traffic comes up.

That is why you'll hear different areas being dispatched over your "Local" channel. They will therefore be simulcasting on multiple freqs when they do that.

"415" is a "Disturbance" and "Family" is the type so 415 Family is a domestic dispute otherwise known as a family disturbance. Listen for 242 which is battery to accompany it or 273.5 I think it is which is spousal abuse or something like that. Can't quite remember after all this time. Might be more than one 273 designation. Lots of times I heard 415F, 242 now @ etc.

They will have morse code on their freqs as required by FCC so you might actually being hearing it being broadcast.
 

cmdrwill

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The LASD uses a busy 'beep' when a car is talking to dispatch so other units will know the radio channel is busy. They also transmit the call sign each half hour in Morse Code with that same beep tone.

And at different times several radio channels are patched together, as Ghstwolf62 mentioned.

And the RTO, 'dispatcher' ,can put the unit radio traffic on the dispatch channel so other units can hear.
 

inigo88

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4. Lastly, how come I'm picking up some LASD audio on frequencies not listed on RadioReference?
Which frequencies are you referring to and what sort of traffic are you hearing? The RR database is based on user submitted data, so sometimes conversations like this in the forums lead to discovering new channels.
 

PaulNDaOC

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C-Code was not brought over to the 480 system when it went live back in the 80's. Other agencies all have the 480 radios in their dispatch centers, so that wasn't the reason.

I was at SCC for 14 years and never heard one word about it, let alone a reason.

Too bad too because it was from at least from an LASD view an easy effective way to quickly furnish outside agencies with important info.

Also, the tones sounded beyond cool on the old 39 mhz system, even better than the old county fire tone-outs IMHO.

Thanks for a great reminder of the good ole days. When police radio was fun.
 

drsn0w

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Which frequencies are you referring to and what sort of traffic are you hearing? The RR database is based on user submitted data, so sometimes conversations like this in the forums lead to discovering new channels.
It's hard to say exactly, I'm using my RTLSDR, and haven't put any significant amount of effort into calibrating it to be accurate lol, so I'm not sure exactly what freqs. Usually I just listen to a channel long enough to hear some identifying speech and then I'll look in the RR wiki to see if there's a frequency in the vicinity and hope it matches up.

Just got a new RTLSDR today, I'm shielding it right now and I'm going to painstakingly calibrate it, so lets see where this leads
 

Ghstwolf62

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C-Code was not brought over to the 480 system when it went live back in the 80's. Other agencies all have the 480 radios in their dispatch centers, so that wasn't the reason.

I was at SCC for 14 years and never heard one word about it, let alone a reason.

Too bad too because it was from at least from an LASD view an easy effective way to quickly furnish outside agencies with important info.

Also, the tones sounded beyond cool on the old 39 mhz system, even better than the old county fire tone-outs IMHO.

Thanks for a great reminder of the good ole days. When police radio was fun.
Your welcome. I'm from back in those days and was out of the area come 92. Still remember some of those 39mhz channels all these years later along with Charlie, Edward, Henry and David channels. 39.88 was Norwalk and when I first got into scanners I had to get the crystal for it.

I can remember when they had the 470 radios for detectives and then units started using them for HTs back then. Lots of unhappy deps when they switched over to the 480 channels although I suppose it improved in time. They thought the 39mhz was much better.

I didn't know they stopped using them though for their crime broadcasts. You're right it was a really good system and definitely got your attention.

I can remember when they called it SRC too though that seems to have changed as well.

Definitely the good ole days. :)
 

PaulNDaOC

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+The facility was renamed in 91 as the time the MDT and CAD system were completed.

Believe it or not that same CAD is still in use 25 plus yrs later.(Intro was introduced one station at a time, with Avalon being the last). It's been peaked and tweeked on a regular basis to add or modify functions,, but essentially functions and resembles the way it looked in 91.

The department's first CAD went online when SRC opened in 73.

Before that it was pencil, paper, and lots of time on the phone with patrol stations.

The 480 system is even older than the CAD, close to 30 yrs. The 470 frequencies were then used as MDT data channels.
 
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cmdrwill

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MDT and CAD in the cars are on some separate band, 800 or up, hard to tell by the curley antennas.. The old 470 MDT freqs are now voice channels.

We still call the "hill" SRC.
 

KMA367

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Your welcome. I'm from back in those days and was out of the area come 92. Still remember some of those 39mhz channels all these years later along with Charlie, Edward, Henry and David channels. 39.88 was Norwalk and when I first got into scanners I had to get the crystal for it.

I can remember when they had the 470 radios for detectives and then units started using them for HTs back then. Lots of unhappy deps when they switched over to the 480 channels although I suppose it improved in time. They thought the 39mhz was much better.
Good stuff, thanks! Those good ol' days made for interesting listening, but of course we had no idea then what was to come in the future. My earliest exposure was to LAPD in the very early 1960s on just about any AM radio at 1730 mc, and then I got some tunable thing for LA City Fire and LASD, but with their being on VHF low, antennas were always a problem.

Here's what LASD had listed in 1964 - yeek! - and then in 1980 as they were just starting that move up to UHF.
.

.
[size=-2]Images are from the annual Police Call Southern California Detail Edition, the "bible" for us monitor / scanner listeners for 40 years. Before his death in 2008, Gene Hughes was kind enough to give me permission to reproduce data from those years online as I saw fit.[/size]
 
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KMA367

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Great info sheet KMA367,

Does anyone know why SRC simulcasted only Lakewood in UHF?
My guess would be that since they were looking at moving from VHF-low up to UHF, it may have been a test area, to see how it worked compared to the low band system, and maybe work out any kinks. LAPD did that before moving everyone from VHF-Hi to UHF, putting Central and Newton Divisions on UHF for a couple years.

In the early 80s though, there weren't enough 470-band (TV Ch 14) frequencies available to meet LASD's needs. It wasn't until TV Ch 16 became available for public safety radio use in L.A. County in the later 1980s that they were able to move to the 482-484 frequencies.
 

PaulNDaOC

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I remember when SRC was referred to as, Station B.
The last RTO from Station 'B' retired about two years ago. She passed on a lot of the legacy to me when I was a trainee.

Anybody interested in LASD legacy would be nicely rewarded by making a trip to the museum in Whittier.
 

PaulNDaOC

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Great info sheet KMA367,

Does anyone know why SRC simulcasted only Lakewood in UHF?
Lakewood was pretty "response time" sensitive then, as compared to most. Each dispatch included the RTO giving out a 'TR' (time received). Some of the stations issued extenders to deps in that thought, but they were lousy, and I'm going to guess the simulcast was possibly so deps could hear their calls when they were Code 6. Just my guess. Starman918 may have some insight to offer about this.

Lakewood back then always did things just a little different and was nicknamed the "Federation" for that reason.
 

xilix

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39.48 still being used

LASO's Frequency Charlie is still in use - It's what LA County uses to transmit Emergency Alert System messages to the various news media outlets.

You will hear very little traffic on it. There is a weekly test and a monthly test.
 
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Starman918

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We had extenders, but they were not issued to everyone, as all of the cars were not equipped with the extender radio transmitter. We had a Lakewood radio car and it had some sort of "docking station type radio" for the handheld. I do remember the time received being put out with the call.

I remember when we were told to go Code 7 and assigned a tag (call) number.

As for the 470 radios, they were used by the station detectives. You could check them out if you were working a special detail. I don't recall SRC broadcasting on these radios, at least not on our channel. The desk had a base station radio so you could communication with them. When calling the desk you would use your unit number followed by, "on the 470." This was because of the multiple frequencies being monitored by the desk.

Aww the memories......
 
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