Trunking System Question

[DonMoose 3]

Maybe someone can answer this, I'm still a tad confused on this whole Trunk'd System. What about it is so much better than the older VHF/UHF system? I know there's different channels for TX/RX, but is that really a big difference? Couldn't that be accomplished with different sets VHF/UHF frequencies?

Hope this isn't too off topic, if so my aplogies. All the other related topics where closed.

[jack10562 414]

We'll create a new thread for your question.

The thing with conventional UHF/VHF frequencies is once a carrier is opened, that channel becomes unavailable for anyone else to use, within range of the signal.

With a trunked radio system there can be as many as 28 frequencies, or channels, that the system talkgroups can utilize. A computer system allocates an available frequency for each and every transmission. You don't hear any other traffic other than what is in your talkgroup.

The Westchester System has 5 channels for the north zone and 6 for the southern zone, in addition to a control channel to operate each zone.

There are 54 emergency ops groups, as well as Hospital and Bee Line Bus Groups

Check out RadioReference.com, for a start

http://wiki.radioreference.com/index.php/Trunking

[TL2L31 8]

Jack, I am receiving the Bee Line system. I think that I have everything set up correctly. Should this be happening?

[jack10562 414]

It sounds as if you have ID SEARCH enabled on your scanner, where you will pick up ALL traffic on the trunked system, or they're enabled under ID Scan.

You will need to reset the scanner's trunked system parameters to ID Scan and program in all the talkgroup ID's you want, and either remove or lock out the bus talkgroup ID's, in order to not hear those.

[DonMoose 3]

We'll create a new thread for your question.

The thing with conventional UHF/VHF frequencies is once a carrier is opened, that channel becomes unavailable for anyone else to use, within range of the signal.

With a trunked radio system there can be as many as 28 frequencies, or channels, that the system talkgroups can utilize. A computer system allocates an available frequency for each and every transmission. You don't hear any other traffic other than what is in your talkgroup.

The Westchester System has 5 channels for the north zone and 6 for the southern zone, in addition to a control channel to operate each zone.

There are 54 emergency ops groups, as well as Hospital and Bee Line Bus Groups

Check out RadioReference.com, for a start

http://wiki.radioreference.com/index.php/Trunking

Thanks, I have a better understanding of how it works now. One thing I didn't see was any type of fail safe though. What happens if the computer that's running everything stops working? Does everything revert back to the VHF/UHF? Or is there anything that would keep it operational without the computer?

[jack10562 414]

Very simply, without the control computer to affiliate the talkgroups, the system can still operate, but not normally.

There are redundant site and zone controllers, however if a site controller or Zone controller or both were to fail, depending on how they're programmed, the radios in a talkgroup can still communicate amongst themselves, as long as they are on the same site (tower) (LAN vs WAN).

Here's much more:

http://www.freqofnature.com/SmartZone101.html

[SteveOFD 176]

I have a couple of questions regarding the Trunked System that I have heard this week.

Today I have heard Sleepy Hollow FD responding to calls using Fire 12 on the System with communications to 60 Control. Is this use permanent or is their VHF system down temporarily? And will they be using 60 Control for dispatch?

Second, Wednesday evening I heard Montrose FD tone out to all members that they would not be using the Trunked System and would revert back to 46.26MHz for all responses. Anyone have any info on why this change?

[Guest WRVFD9000]

I have a couple of questions regarding the Trunked System that I have heard this week.

Today I have heard Sleepy Hollow FD responding to calls using Fire 12 on the System with communications to 60 Control. Is this use permanent or is their VHF system down temporarily? And will they be using 60 Control for dispatch?

Second, Wednesday evening I heard Montrose FD tone out to all members that they would not be using the Trunked System and would revert back to 46.26MHz for all responses. Anyone have any info on why this change?

I am a little confused, I dont know a whole lot about this system. Are they using the 46.26 low band frequency for there primary dispatch and then just using the trunked for there on scene communications and fire ground communications.

[SteveOFD 176]

I am a little confused, I dont know a whole lot about this system. Are they using the 46.26 low band frequency for there primary dispatch and then just using the trunked for there on scene communications and fire ground communications.

The theory behind the Westchester County Fire/EMS Trunked System is that agencies (FD/EMS) will be dispatched on their existing paging system. Response and communications to 60 Control will be on the Trunked System. On scene communications will be on the eight UHF Fireground frequencies. This is how it was designed to work. No one is mandated to use this system or abandon their existing systems.

I posted the above questions to find out more about who is, and who isn't, using the new system.

[DaRock98 76]

I also have a question. How come I hear Irvington use the system to call in responding and what not but 60 never acknowledges them?

[SteveOFD 176]

I also have a question. How come I hear Irvington use the system to call in responding and what not but 60 never acknowledges them?

If you are hearing one half of the conversation you should hear the other half, they both work from the same towers. On a trunked system conversations do not go directly from radio to radio. The transmission goes from the transmitting radio to the nearest repeater tower then to the receiving radio.

So, if you are receiving one half of the transmission (from the tower), you should hear the other half (also from the tower).

[jack10562 414]

I also have a question. How come I hear Irvington use the system to call in responding and what not but 60 never acknowledges them?

Do you have a trunk tracking scanner, or have you just programmed in the trunked system frequencies into a regular scanner?

[DaRock98 76]

Do you have a trunk tracking scanner, or have you just programmed in the trunked system frequencies into a regular scanner?

I have a trunk tracking scanner and I hear everyone else fine(both sides of convo) it seems to me that 60 does not acknowledge just them.

[Remember585 815]

I have a trunk tracking scanner and I hear everyone else fine(both sides of convo) it seems to me that 60 does not acknowledge just them.

60 Control doesn't acknowledge Irvington FD because we aren't their dispatchers. BUT, if IFD is going to a call dispatched by us, then we acknowledge them.

It's no different in Irvington then when they used 46.26 to "communicate" and got no answer from their PD. Now it's just on Fire 14.

Most of the 14 Battalion is using the trunked system, whether it's for every run or whenever they need to communicate with others, including 60 Control.

Departments like Ardsley, Hastings, Tarrytown, Sleepy, Elmsford, Hartsdale, etc. are using the trunked system to talk to 60 Control because they have their own frequencies, but they aren't monitored by 60 Control nor in most cases, do their neighbors monitor them.

The trunked system is a great tool that we all can use, we just need to understand it more and get the hang of it.

[xchief2x 79]

Steve

Montrose switched to fire 10 on a trial basis, they switched back to 46.26 due to severla dead areas in their district. No radio system is 100%.

[SteveOFD 176]

Steve

Montrose switched to fire 10 on a trial basis, they switched back to 46.26 due to severla dead areas in their district. No radio system is 100%.

Thanks Chief