CHP Porterville / Visalia

[officer_415]

There are two base frequencies listed in the DB for CHP Porterville/Visalia, does anyone know which one is correct? Looks like people first reported hearing 45.10 back in 2016, but I don't know if it replaced 42.44 or what. Pink 2 was originally slated to be 45.10 Rx / 42.62 Tx, 123.0 PL (but I know the frequency plans have changed a lot since they started rolling out the CHPERS updates over a decade ago).

 

[vagrant]

I just listened to both.
42.44 MHz = Dispatch and Vehicles
45.10 Mhz = Vehicles

I then watched them both simultaneously on the waterfall and confirmed the above. Dispatch does not come through on 45.10. Also, the signal level is the same for vehicles on 45.10, so I figure they are being repeated.

 

[officer_415]

Strange, I wonder what the purpose is. Are the mobiles still on 42.76 and/or did you see any other inputs?

 

[vagrant]

The mobiles might be on 42.76. I am not in that area, but my system is able to receive the stronger power signals on the frequencies I noted.

I see whatever the RR database has as far as input. Other dispatch frequencies in the valley have been accurate of late.

 

[officer_415]

Alright, interesting. Thanks!

 

[emt_531]

I just added 45.10 but I always listen to the other 2.

 

[es93546]

I just listened to both.
42.44 MHz = Dispatch and Vehicles
45.10 Mhz = Vehicles

I then watched them both simultaneously on the waterfall and confirmed the above. Dispatch does not come through on 45.10. Also, the signal level is the same for vehicles on 45.10, so I figure they are being repeated.

I don't know what you mean by "the waterfall."

Also, the CHP does not have repeaters, they feed the mobile frequency audio through to the base frequency audio. They do most of this in urban areas and the large rural areas don't have this feature. That is because units are more spread out both in distance and topography, with units being able to only hear one, maybe two, remote base stations at the same time. This mobile to base patch would not be heard by the majority of units so there is not an advantage, except for the units currently working that one site. In addition remote base station receivers use a voting system and a unit might be going between sites intermittently in the same transmission or a series of transmissions.

In addition, since vehicles use both the mobile and base frequencies (car and station in CHP lingo) with the mobile frequency transmitted to remote base stations and car to car communications being on the base frequency, you often can't hear the mobile frequency at all, as it can be buried in terrain while the remote base is on top of a peak transmitting at 4-5 times the power. In rural areas not using the mobile frequency to base frequency patch you only hear units transmitting on the base frequency if they are close or topography/distance allows.

Strange, I wonder what the purpose is. Are the mobiles still on 42.76 and/or did you see any other inputs?

Presumably, the 45.10 base should have a mobile of 42.620 as you mentioned. The database does not show a Pink 2 mobile for Porterville/Visalia. The only other Pink 2 in the RR database shows a different base frequency, this for West L.A. in the Southern Division. I could probably dig back in my written material and find the 45.100/42.620 pairing though. The pairing shown in the database, 42.440/42.760 should be current. Have you heard any mobiles on 42.760? I guess not as otherwise you would not have posed the question you have in your second post. Transmitting on both Pink and Pink 2 at the same time would seem to indicate that the area offices are in the midst of a transition. However, I haven't followed these area offices closely, so I don't know how long this transition has been the case. I wonder if in this transitional period they are using 42.76 as the mobile for both?

If no one else on RR knows the answers, my suggestion would be to drive to one of their remote base mountain top sites, then listen as mobiles transmit to dispatch and see if both the Pink and Pink 2 base frequencies have the same reply transmissions. It would require at least two scanners and decent antennas. It is surprising how well you can hear the mobiles from on of the CHP remote bases. I just saw your location is Marin County, so this suggestion might not be very easy.

 

[officer_415]

I don't know what you mean by "the waterfall."

I assume he means a waterfall display spectrum analyzer, which would allow him to see simultaneous transmissions on different frequencies.

Also, the CHP does not have repeaters, they feed the mobile frequency audio through to the base frequency audio. They do most of this in urban areas and the large rural areas don't have this feature. That is because units are more spread out both in distance and topography, with units being able to only hear one, maybe two, remote base stations at the same time. This mobile to base patch would not be heard by the majority of units so there is not an advantage, except for the units currently working that one site.

True, the CHP "auto repeat" function is not a true repeater, but it behaves like one as far as a scanner listener is concerned. Most, if not all of the Porterville and Visalia CHP areas are covered by the Blue Ridge transmitter, so the auto repeat function would be beneficial for the Pink.

I wonder if in this transitional period they are using 42.76 as the mobile for both?

45.10 was first reported in 2016, so I don't think it's still a transitional period. More like an upgrade that was started and never completed.

 

[PaulNDaOC]

True, the CHP "auto repeat" function is not a true repeater, but it behaves like one as far as a scanner listener is concerned. Most, if not all of the Porterville and Visalia CHP areas are covered by the Blue Ridge transmitter, so the auto repeat function would be beneficial for the Pink.

That's a good explanation for the typical listener rather than calling it a duplex patch or whatever referring to it as the repeater conveys what you mean.

On the Northern Coast, Humboldt dispatch covers that county as well as Trinity to the east and Del Norte to the north on one frequency covering more than 100 miles north to south.
They use a repeater which remains on the same transmit site until the dispatcher changes it manually to another. For voice transmissions the site used is either a default site, manually selected,, or voter selected if done within a certain period of time in response to a voted incoming radio signal.