dumb question time

[radiogrrl]

okay, I'm brand new here and I know VERY little about radio comms as you will no doubt see by my next question! (thats why I've joined the forum - expect lots of not-too-bright questions in the next few weeks!)

How do you try to describe a trunking radio network in terms of its capacity ???

Can you define the size of a network by the number of users, the way the channels or talk groups are set up or by the bandwidth available ?

Sorry if this question sounds really vague, but I've been asked to try to determine how much a particular network may be being utilised (ie underutilised) and I have to ask the relevant people questions about capacity but I'm at a loss as to where/how to even start!

- any hints/tips?

Its a motorola smartnet network btw - including voice, data and paging sub networks.

 

[N_Jay]

okay, I'm brand new here and I know VERY little about radio comms as you will no doubt see by my next question! (thats why I've joined the forum - expect lots of not-too-bright questions in the next few weeks!)

How do you try to describe a trunking radio network in terms of its capacity ???

Can you define the size of a network by the number of users, the way the channels or talk groups are set up or by the bandwidth available ?

Sorry if this question sounds really vague, but I've been asked to try to determine how much a particular network may be being utilised (ie underutilised) and I have to ask the relevant people questions about capacity but I'm at a loss as to where/how to even start!

- any hints/tips?

Its a motorola smartnet network btw - including voice, data and paging sub networks.

In general it is described by the number of chanels and the number of sites and the number of units it is supporting.

 

[fmon]

- any hints/tips?

Its a Motorola smartnet network btw - including voice, data and paging sub networks.

If you click on Home above then select Trunking Information, you will find Motorola Trunking Systems in the several types available. Smartnet has a section.

 

[loumaag]

BTW, welcome to the site!

 

[radiogrrl]

thanks!

Thanks for the responses and the welcome! :wink:

I'd looked in the motorola section previously but still just wanted some confirmation that it wasn't any more complicated than listing channels, users and sites.

- So these types of systems really wouldn't ever be overloaded, would they? I mean it seems that you have almost unlimited access for users - is this true?

 

[N_Jay]

Re: thanks!

Thanks for the responses and the welcome! :wink:

I'd looked in the motorola section previously but still just wanted some confirmation that it wasn't any more complicated than listing channels, users and sites.

- So these types of systems really wouldn't ever be overloaded, would they? I mean it seems that you have almost unlimited access for users - is this true?

Nope, poor planning can easily overload a system!

System management is a sugnificant issue.

 

[scanfan03]

Re: thanks!

Thanks for the responses and the welcome! :wink:

I'd looked in the motorola section previously but still just wanted some confirmation that it wasn't any more complicated than listing channels, users and sites.

- So these types of systems really wouldn't ever be overloaded, would they? I mean it seems that you have almost unlimited access for users - is this true?

Per site you can only have 4 control channels, with one always buzzing, and I think 27 other Voice frequencies (Is this right, is it 28 channels including the CC?). How many sites do you have, each site can become its own trunking system easily doubling the amount of TGs you can put on it.

 

[radiogrrl]

how many sites?

About 30 sites.

Why only four control channels?

:?:

 

[N_Jay]

Re: how many sites?

About 30 sites.

Why only four control channels?

:?:

Alternate control channels are needed only if a control channel fails.

The limitation is 4 PER SITE.

The total channel limitation per site is usually driven by the ability of the controil channel to send out all the outbound assignment messages and keep access time acceptable.

The number of sites is driven by coverage requirments, and can go quite high.

 

[boy_ryan22]

Heres an even dumber question... what would happen if you put a group of trunking frequencies in to a regular scanner? What would i hear? if i scaned them would i pick up anything?

Thanks for all your help.

 

[W4KRR]

Heres an even dumber question... what would happen if you put a group of trunking frequencies in to a regular scanner? What would i hear? if i scaned them would i pick up anything?

You would hear bits and pieces of unrelated conversations. You might hear a police dispatcher dispatching a robbery call, then suddenly hear a street crew talking about a pothole on the same frequency. You wouldn't be able to track one complete conversation.

 

[fmon]

Heres an even dumber question... what would happen if you put a group of trunking frequencies in to a regular scanner? What would i hear? if i scaned them would i pick up anything?

Thanks for all your help.

Reasonable question, and welcome. The Control Channel assigns the next available freq and the ID for the communications, thus lock it out and scan the rest. Don't forget to unlock a previous CC each time it changes. You won't be Trunk tracking, but you will be able to randomly scan the system. If the system is digital, it would be useless to try to listen.

 

[boy_ryan22]

Thanks i tried it last night on vancouver fire freqs and got a bit of dispatching and a bit of other stuff.. works better than i thought...

Now for the system frequencies it says Red* are Primary Control Channels, Blue* are alternate control channels.

Whats the difference beteween them?

 

[INDY72]

PRIMARY CC's are the main ones used as CC's,.. and the others are used as alternates in the rotation scheme. All Motorola 800 TRS systems are designed to have 4 CC's... with two usually as the main ones, and two as alternates .... In the beginning of trunking, every M system rotated the CC's on a daily basis for better usage of the system. Now only a few still rotate that often, and some do not ever rotate unless there is trouble on the system. I have only noticed CC rotation on EDACS on rare occaisions......