LA County Sheriff

[wYtEbOyFoLyPh]

I see that LA County Sheriff has CSQ... how do they do that? I thought you had to have a PL or DPL to access a repeater... thanks for the help.

 

[FPO703]

They use Digital modulation. Meaning, you don't need a PL or DPL, But, a NAC (Network Access Code) which is almost the same thing as PL/DPL.

 

[Mick]

The output of LASD's repeaters is carrier squelch, but the input tone to access most of them is 186.2 Hz. Since they are the sole users of their frequencies they don't really need pl protection.
The other replier mentioned digital, LASD does not have a digital system, he may have been confused with LAPD who does use a P25 digital system.

I see that LA County Sheriff has CSQ... how do they do that? I thought you had to have a PL or DPL to access a repeater... thanks for the help.

 

[mdulrich]

I thought you had to have a PL or DPL to access a repeater... thanks for the help.

You don't HAVE to use PL or DPL to access a repeater if the system is set up that way. There will probably be problems with the system repeating distant traffic. There are repeaters in the ham bands that don't use PL.

Mike

 

[Station51]

LASO-Related info

If you are listening to an SO station, you'll hear "Beep Beep Beep" while the unit is transmitting, but if you are local to what you are monitoring you can put the input freq in a different channel or another radio and monitor the unit as well.
Also the "L Tac" for that area is a simplex freq, so the closer they are to you the stronger the signal.
At times the units will talk to each other on the output (Dispatch) channel on simplex also. Only units close by hear them and it doesn't interfere with the dispatch channel.
The Sheriff's pass off stations to one another so you may be listening to West Hollywood and Malibu, and in the blink of an eye you may be listening to West Hollywood and Lynwood.
Their repeaters are pretty strong. I frequently listen to Lakewood (One of the strongest) while mobile in Riverside County, in fact today I was in Redlands (SBDO County) and listening to an assistance call in Norwalk.

 

[SCPD]

It has been awhile since I tried it, but the last time I monitored the mobile frequency for the dispatch channels, they were using voice inversion scrambling. Is this still true?

 

[2wayfreq]

I havent heard of any speech inversion. I believe the few INV channels are in DES encryption mode but its only a handfull. They are getting rid of thier M-RK portables (470-500 MHz) and are aquiring XTS-3000s (450-520 MHz) for greater city fire/ PD interoperabilty. Its likely that they will get rid or the GE Mastr repeaters and get Quantars. Many deputies still like the half-duplex system as it is and "fear change". If they do go for it, it will take a lot of time and money.

 

[Starman918]

From a previous post: Also the "L Tac" for that area is a simplex freq, so the closer they are to you the stronger the signal.

L Tac frequencies are repeater frequencies. Sometimes Deputies will go to simplex or direct as they call it, when communicating short distances. They will oftentimes do that with details such as parades, or other community events. This limits interference with communications between the station desk and field units. Also, when field units are talking to the air units, the air unit will sometimes go to simplex or direct to cut down on intereference with other repeaters countywide.

Field units use the simplex side of Dispatch, but I believe it is against Departmental policy.

To my knowledge, LASD has never used voice inversion scrambling.

Tom

 

[Thunderbolt]

To my knowledge, LASD has never used voice inversion scrambling.

Tom

As I understand it, from listening to LASD, back when they were on 39 MHz. One of their specialized units did use voice inversion scrambling, but that was all I ever heard here in Michigan, when skip was rolling in. None of the dispatch or regular car-to-car channels ever used scrambling. However, it's possible they could have used it on other bands.

73's

Ron

 

[Starman918]

Someone mentioned digital earlier. I believe all of the links to the repeaters were converted to digital not to long ago.
Tom

 

[SCPD]

Sometimes Deputies will go to simplex or direct

We called using the repeater output frequency "Channel 1" in my earliest years with the U.S. Forest Service. The repeater was always on Channel 2 in USFS radiios, no matter where you went in the agency. Other agencies called it "car to car". In the 80's as we began to get programmable radios with other agency's frequencies in them, we began to talk on lots of different systems on a frequent basis. It was decided in interagency meetings that everyone had the simplex frequency of their repeaters ouput in a different order, so the USFS method of saying "Channel 1" was not common. The CHP was used to saying "the S channel" or "the C channel" so that really got confusing when they would use the additional channels in their extenders to speak on VHF systems. In addition going simplex on another agency's system meant going to whatever channel it was programmed into your radio and certainly not channel 1. It was decided that saying "car to car" was too lengthy. Many radios were coming out with a switch that said "Direct/Repeater" at that time also. So the word "direct" was chosen and accepted for interoperability purposes.

We got so accustomed with the term we began to stop using the old "Channel 1" label even when talking to each other on our own system. On fires all over the country I heard people from many other areas and agencies start to use "direct" also. In the radio industry the term "simplex" is easily understood, but for the vast majority of users it sounds a bit foreign. Direct and repeater fit logically together and asking the users to say "simplex and duplex" is not realistic. Heck, I'm confused when radio people say duplex as full duplex is transmitting and receiving simultaneously. When using a repeater it is actually "semi-duplex".

If LASO deputies use the term "direct", they are not the only ones!

To my knowledge, LASD has never used voice inversion scrambling

I definitely heard speech inversion being used sometime during the period 1987 to 1992. It was only used on the mobile side and not by the dispatcher. 1987 was about the time the LASO phased out lowband and I don't remember if speech inversion was used on the mobile side of their dispatch channels. I remember programming the BC-760's in my cars and my BC-200 handheld with the mobile frequency of the dispatch channels I was going to listen to when visiting my sister in Acton for family events. I remember slaving over the scanners, programming them before each trip, usually late at night before leaving the next day. I remember my disappointment when all the moibile frequencies sounded like a duck. My carefully thought out programs and painful programming efforts resulted in unusable space being taken up where I had needs for other frequencies. I remember it so well because I was so disappointed my great programs had to be changed and in those days if you inserted a frequency in a bank, you had to reprogram all the other channels in that bank in order to make the change.

I never tried listening to the mobile frequency much at all as I lived anywhere from 350 to 1500 miles from L.A. County during their use of lowband. I heard some great skip from 1979 to 1987 and could always tell when I was receiving them. The dispatchers had the fastest tongues in the west except for Chick Hern's and their words were always followed by the famous beep, beep, beep . . . . . I was visiting LA in the seventies when I came out of a theater someone had driven me to and wondered what jurisdiction we were in (it was a real checkerboard area) when I heard the beeps without seeing the officer. Questioned asked and answered!

 

[Starman918]

I can tell you that the Station that I work at has never used voice inversion encryption in their mobile units. That goes for the low-VHF and their current UHF system. I know they have encrypted radios for their special units.
I know that LASD experienced tremendous skip problems when the low-VHF system was in use. Several times we would hear units asking for help, only to find that it was actually a unit in another state asking for assistance. I believe that they finally added a private line tone to cut down on the skip.
Tom

 

[SCPD]

The mobile frequency I heard the speech inversion on was being used for the Antelope Valley.

 

[blake23]

So do I understand this correctly, that to monitor LASD dispatch and units, you need both the base and mobile frequencies entered into the scanner, as if you were to monitor the CHP.

 

[Mick]

In order to hear the entire conversation you would need to tune in the dispatch channel and the mobile channel, 3 MHz higher. Using two scanners may be easier too.

So do I understand this correctly, that to monitor LASD dispatch and units, you need both the base and mobile frequencies entered into the scanner, as if you were to monitor the CHP.

 

[iepoker]

From my location, 1500' above Chino Hills/Pomona, I can hear many of the San Dimas units on the input channel with no scrambling or speech inversion.

Thanks for the tip, all this time I have let those annoying beeps keep me away from LASO

 

[SCPD]

From my location, 1500' above Chino Hills/Pomona, I can hear many of the San Dimas units on the input channel with no scrambling or speech inversion.

This is good information. When I write my file for southern California I'm going to program in the mobile for each dispatch channel I include. Having two scanners is a great idea as the scanner won't move on to the mobile frequency as is stays on the dispatch frequency because of the tranmission of the beeps.

 

[Starman918]

That is a good idea to program in the mobile frequency first. Something to keep in mind though is that when there is routine traffic, you will hear the "busy tone" on the dispatch channel. Emergency traffic will most often be "patched" so you can hear mobile transmissions.
Tom

 

[zackhenderson]

Sorry to bring up an old post, but I was wondering why LASO even has the beeps when a field unit is talking...seems like it would be a real annoyance!

Happy holidays everyone!

 

[SCPD]

Since the mobile traffic is not repeated for other mobiles to hear, they transmit the beep to indicate the mobile frequency is being used, greatly reducing mobile units doubling with each other.