CHP Statewide Frequencies Help???

[cj5]

Looking through the systemwide frequencies Department of the Highway Patrol (CHP) Scanner Frequencies and Radio Frequency Reference, I don't understand what the information in the parentheses means. For example, under Tactical it shows 45.0200 Base - TAC 1 (Los Angeles Area - 103.5 PL), and further down it has 39.9200 Base - TAC 4 (Border Area). I don't understand this information. It confuses me as to whether I should be putting this frequency into my scanner. Should I put in the 45.0200 frequency with the PL tone for my area's division, and RR is telling me that if I want Los Angeles area traffic use 103.5 for the PL tone? If so why note the Border Area specification? Border division usually utilizes the 162.2 PL tone, so why note this? I'm not criticizing, I'm just a bit confused, and would appreciate some clarification as to how this works. Any ideas?

 

[gmclam]

CHP CT values

Looking through the systemwide frequencies Department of the Highway Patrol (CHP) Scanner Frequencies and Radio Frequency Reference, I don't understand what the information in the parentheses means. For example, under Tactical it shows 45.0200 Base - TAC 1 (Los Angeles Area - 103.5 PL), and further down it has 39.9200 Base - TAC 4 (Border Area). I don't understand this information.

Let's start off by reading the header above that section. It states: 'Output PL tone varies by division. (Southern Divison may use 136.5 PL.) Mobile units can be found in simplex on the base frequency when transmitting in "Car-to-Car" mode.'

So, to me, that means for the Los Angeles division, the CT is 103.5 on 45.020 MHz. I would guess that 39.9200 MHz uses a CT of 136.5, but I'll agree it is UNCLEAR. The DB should clearly state the CT/DC value next to each frequency.

It confuses me as to whether I should be putting this frequency into my scanner. Should I put in the 45.0200 frequency with the PL tone for my area's division, and RR is telling me that if I want Los Angeles area traffic use 103.5 for the PL tone?

As you may or may not know, CT or PL values are optional and not required. All your scanner will need to pick up the signal is the frequency. Of course I recommend using CT values on low band signals because of the large amount of atmospheric noise in that band.

If so why note the Border Area specification? Border division usually utilizes the 162.2 PL tone, so why note this? I'm not criticizing, I'm just a bit confused, and would appreciate some clarification as to how this works. Any ideas?

I agree that this entry is confusing. Los Angeles, Southern, Border, San Diego; many people looking here might not understand what is a division and what is not.

I thought the area that included Los Angeles is the Southern Division, so why note 45.020 as Los Angeles. Are we saying that the CT is 136.5 in the Southern Division except when in Los Angeles itself?

And with 39.9200 being noted as Border area, what is the CT? Since nothing else is stated, one is led to believe it is 136.5, since the border is in the southern part of the state.

 

[cj5]

gmclam,

Thanks for the breakdown. The Los Angeles one in particular is fairly more clear than the Border one. SO, the Border one as well as the Golden Gate area one seem to tell me that it is only for those areas alone, and not used systemwide. That's where the confusion lies. Anyhow, I hope an admin will step in eventually and clear this up for us. Thanks, again.

 

[K6CDO]

The reason for limiting the Division tones was the older radio equipment. When the CHP was using MICORs in the 1970s and 1980s, the radios would support one or two CTCSS tones. When the CHP moved to GE RANGRS in the late 1980s, the limitation on CTCSS tones was lifted, but the number of tones in use was not expanded due to the expense of converting all of the mountain-top infrastructure and reprogramming the mobile radios (the original programmer was 'clunky' by todays' standards). In some cases, mixes occurred on some sites due to frequency combinations, and passed through the system due to the common CTCSS tone for the area.

With the total replacement of the infrastructure under the CHPERS project, the State is free to mix tones along with channels, by geographic area. So, we will no longer see the hard use of Division tones in the future.