San Benito County/Hollister Police Switching to Digital

[UnHumanReactions]

According to this new article, https://bit.ly/2CYTeF8 , Hollister Police is going to be switching their radios to a new digital system since their current and outdated system is very unreliable with the terrain of San Benito County. They are contracted with a local radio shop in Hollister, called EVS or Emergency Vehicle Specialists. They specialize in Kenwood radios only, and I'm assuming are going to be utilizing the Kenwood digital spec of NEXEDGE or NXDN. The news article doesn't specify on whether encryption will be used or not, but it did say that they will be installing 6 new digital repeaters around the city of Hollister. With this, I can assume it will be a trunking system, however, while searching through the database, I found a license of WQYM909, which has 6 locations of FB2 which is a repeater and the emission 4K00F1W which is NXDN 6.25 kHz digital voice and data (IDAS, NEXEDGE) in the wiki, which seems to match up up with their new system, but it is conventional, not trunking. What do you guys think? Is this their new system already in the DB?

 

[mmckenna]

I'd be surprised if they go trunking. SBSO is a pretty small/low budget department. Usually the station class (FB2, etc.) would be different if they were going with trunking.
Also, VHF pairs are in short supply in this area. Adding additional VHF pairs would be a challenge. Unless they took their other existing VHF pairs and rolled them into a trunking system, but I doubt that would gain them much.

Radio coverage has always been an issue down there. Low Band probably would have been a good choice for that area.

Hollister PD has also been purchasing Kenwood NXDN radios for a few years now.

 

[UnHumanReactions]

I'd be surprised if they go trunking. SBSO is a pretty small/low budget department. Usually the station class (FB2, etc.) would be different if they were going with trunking.
Also, VHF pairs are in short supply in this area. Adding additional VHF pairs would be a challenge. Unless they took their other existing VHF pairs and rolled them into a trunking system, but I doubt that would gain them much.

Radio coverage has always been an issue down there. Low Band probably would have been a good choice for that area.

Hollister PD has also been purchasing Kenwood NXDN radios for a few years now.

So do you think WQYM909 is their new system? Also, how would they link all 6 repeaters? I wonder if it would be like a voting system, whichever repeater gets the strongest signal transmits?

 

[mmckenna]

I don't know, last time I talked with the Kenwood rep about it was in 2017.

Natively they do IP linking, but could be doing simple two/four wire link to a voter.

They are dispatched by Santa Cruz County Netcom, so the interface to the system will need to be something that can be hauled over from Santa Cruz pretty easily.

 

[mmckenna]

I was swapping e-mails with the local Kenwood rep just now on a different subject. I asked him if he's heard anything about this system. I'll let you know what I hear.

 

[Giddyuptd]

If it's Kenwood they'll probably go nx5200 series. Regardless if they go nxdn those can have p25, dmr added if needed so interior won't be issue with others using p25 or dmr in their area

 

[Giddyuptd]

So do you think WQYM909 is their new system? Also, how would they link all 6 repeaters? I wonder if it would be like a voting system, whichever repeater gets the strongest signal transmits?

Probably a voting system, but most go for the microwaved sites and let the system controllers on conventional do the work over the radio being the one to switch or have users switch to a specific site. Same frequency or can be different depending on what voting system you go for. Many just go with the same freq and let the microwave and controllers do the work. User stays on same channel.

 

[UnHumanReactions]

If it's Kenwood they'll probably go nx5200 series. Regardless if they go nxdn those can have p25, dmr added if needed so interior won't be issue with others using p25 or dmr in their area

They already have NX-200's and NX-700's from a previous grant they got from Department of Homeland Security a while ago.

 

[UnHumanReactions]

I don't know, last time I talked with the Kenwood rep about it was in 2017.

Natively they do IP linking, but could be doing simple two/four wire link to a voter.

They are dispatched by Santa Cruz County Netcom, so the interface to the system will need to be something that can be hauled over from Santa Cruz pretty easily.

I believe the current system with Santa Cruz Netcom is done over the internet. There's no direct line from Santa Cruz to Hollister repeater. A computer get's Netcom audio and then goes to a mobile radio, probably NX-700, to the repeater. The downside to this is dispatch can't hear anything while they are transmitting, and units in the field can cover dispatch by accident by creating a heterodyne when multiple units transmit.

 

[ScannerDude244]

So they are leaving out fire and SO?

 

[UnHumanReactions]

So they are leaving out fire and SO?

Yes, I believe Fire and Sheriff's Office will remain on analog until they can get more digital repeaters to cover the rest of the county,

 

[KK6ZTE]

Well good luck with that new system. Interesting choice of vendor...

 

[flux4201]

I believe the current system with Santa Cruz Netcom is done over the internet. There's no direct line from Santa Cruz to Hollister repeater. A computer get's Netcom audio and then goes to a mobile radio, probably NX-700, to the repeater. The downside to this is dispatch can't hear anything while they are transmitting, and units in the field can cover dispatch by accident by creating a heterodyne when multiple units transmit.

Netcom uses a T1 that is muxed out to 4 wire DS0's which control a base station that talks to the various existing repeaters.

 

[UnHumanReactions]

Netcom uses a T1 that is muxed out to 4 wire DS0's which control a base station that talks to the various existing repeaters.

Sorry, can you explain it a little more? I don’t know what T1 and DS0 means.

 

[mmckenna]

Sorry, can you explain it a little more? I don’t know what T1 and DS0 means.

A T-1 is a type of telecom circuit. Often from the local exchange carrier. It's a digital service, often with a transmit pair of wires and a receive pair of wires (there are ways to multiplex that onto one pair, but that's off topic…).
The T-1 runs a 1.544MB/s
You can put 24 voice circuits on a T-1.

Often what they do is get a point to point T-1 circuit from AT&T. They install a piece of equipment on each end that breaks the T-1 out into those 24 channels. Each one of those channels is referred to as a DS0.

Each DS0 can carry a channel of radio traffic.

So, a T-1 circuit between NetCom and Hollister. At the NetCom end, they have a box that allows them to connect several (up to 24) voice grade DS0's. The NetCom radio console (I believe they are still running Zetron) would connect the Hollister PD channel to one of the DS0's.

The other end of the T-1 circuit would be in Hollister. There they would have a similar box that splits the T-1 circuit out to the 24 DS0's. One of those DS0's would feed the Hollister PD radio system.

Just a phone company way of cramming a bunch of services on to the minimum amount of cable.

In reality, the two pairs for the T-1 connect back to the local Central Offices (Santa Cruz 01 at 709 Center Street and Hollister 11 at 540 Sally Street)
Between the two Central Offices (CO's), the signals are multiplexed onto fiber optic cable with thousands of other services.

T-1 circuits from the phone company are kind of expensive, but they work well. They are often cheaper than setting up a point to point microwave link (Santa Cruz to Hollister would require a mid point microwave repeater). Most radio guys are often more familiar and comfortable with T-1 circuits.
Problem is, AT&T wants out of the T-1 business. Eventually these sorts of radio circuits will get moved over to IP connections.

 

[flux4201]

So do you think WQYM909 is their new system? Also, how would they link all 6 repeaters? I wonder if it would be like a voting system, whichever repeater gets the strongest signal transmits?

If it was voting all sites would have the same MO (mobile input) frequency, since they have multiple site locations in the license and multiple FB2's (fixed base repeater transmit frequencies) with each their own MO frequency its probably not a system with voting receivers.. If it was voting there would likely only be one MO frequency on the license as their coverage area is well within the standard licensed 40km radius. If they had a coverage area greater then 40km you would see the same MO frequency licensed around another FB2 location to give them whatever extended coverage they needed.

Most likely HPD will be going nexedge conventional digital, where all sites will be conventional digital repeaters IP linked and beacon every so often so radios can roam about the system autonomously.

 

[UnHumanReactions]

A T-1 is a type of telecom circuit. Often from the local exchange carrier. It's a digital service, often with a transmit pair of wires and a receive pair of wires (there are ways to multiplex that onto one pair, but that's off topic…).
The T-1 runs a 1.544MB/s
You can put 24 voice circuits on a T-1.

Often what they do is get a point to point T-1 circuit from AT&T. They install a piece of equipment on each end that breaks the T-1 out into those 24 channels. Each one of those channels is referred to as a DS0.

Each DS0 can carry a channel of radio traffic.

So, a T-1 circuit between NetCom and Hollister. At the NetCom end, they have a box that allows them to connect several (up to 24) voice grade DS0's. The NetCom radio console (I believe they are still running Zetron) would connect the Hollister PD channel to one of the DS0's.

The other end of the T-1 circuit would be in Hollister. There they would have a similar box that splits the T-1 circuit out to the 24 DS0's. One of those DS0's would feed the Hollister PD radio system.

Just a phone company way of cramming a bunch of services on to the minimum amount of cable.

In reality, the two pairs for the T-1 connect back to the local Central Offices (Santa Cruz 01 at 709 Center Street and Hollister 11 at 540 Sally Street)
Between the two Central Offices (CO's), the signals are multiplexed onto fiber optic cable with thousands of other services.

T-1 circuits from the phone company are kind of expensive, but they work well. They are often cheaper than setting up a point to point microwave link (Santa Cruz to Hollister would require a mid point microwave repeater). Most radio guys are often more familiar and comfortable with T-1 circuits.
Problem is, AT&T wants out of the T-1 business. Eventually these sorts of radio circuits will get moved over to IP connections.

Ah, gotcha. I do remember reading about the merger with Hollister and Netcom back in 2012 and them mentioning AT&T a lot in the plan the wrote up on how do it. It used to be available on Google in a PDF but I can't find it anymore. Really interesting stuff. Thanks for the explanation.

 

[UnHumanReactions]

If it was voting all sites would have the same MO (mobile input) frequency, since they have multiple site locations in the license and multiple FB2's (fixed base repeater transmit frequencies) with each their own MO frequency its probably not a system with voting receivers.. If it was voting there would likely only be one MO frequency on the license as their coverage area is well within the standard licensed 40km radius. If they had a coverage area greater then 40km you would see the same MO frequency licensed around another FB2 location to give them whatever extended coverage they needed.

Most likely HPD will be going nexedge conventional digital, where all sites will be conventional digital repeaters IP linked and beacon every so often so radios can roam about the system autonomously.

So all of the repeaters will be transmitting the same audio? And if that's the case, I would only to need to monitor 1 repeater to get all of the radio traffic?

 

[flux4201]

So all of the repeaters will be transmitting the same audio? And if that's the case, I would only to need to monitor 1 repeater to get all of the radio traffic?

Correct, should they build out the new system like i stated, all sites would transmit the same audio and you would only need to monitor 1 site/frequency.

 

[UnHumanReactions]

Correct, should they build out the new system like i stated, all sites would transmit the same audio and you would only need to monitor 1 site/frequency.

Ok, cool. Thanks for the info!