Are All Frequencies Supposed To Be Used Equally On A Motorola Capacity Plus System?

[JASII]

Right now, I am scanning conventionally the four frequencies of a for profit Motorola Capacity Plus system near me. When I check the History Log, only three of the four frequencies show any activity after hours of listening. Now I know the fourth frequency has been active in the past because I have logged the TGIDs and UIDs that were on the other frequencies on the fourth frequency. Is it possibly that just one repeater is having issues right now or can Capacity Plus systems programmed to use certain frequencies first and save others in reserve? From what I have read in the past, the frequencies are rotated equally, but it sounds to me that perhaps not all systems actually work that way.

I did read through some older posts here and it seems as if others noticed that same behavior on their Capacity Plus systems, too. Does that mean that the Rest Channel moves to the first available frequency rather than rotating equally between all frequencies in a system?

 

[nd5y]

Some types of trunked systems can have certain overflow voice channels that are only used when all other channels are busy. I don't know if Capacity Plus is that way.

 

[n9mxq]

The Cap+ system at the local auto plant is the same way.. As ND5Y said, unless everything is busy with traffic, they're not used.

 

[R8000]

There's a setting in CAP+ to rotate the rest channel. This will allow all more even useage of the repeaters. It's not recommended to leave this feature off as if there's a receiver failure of the rest channel, the system is dead in the water. Rotating them allows some traffic to still flow until service can be performed. It's also important to know that CAP+ only rolls traffic off the rest channel is both timeslots are being used. When the second conversation starts, the rest channel is then rolled to the next repeater.

DMR rest channels and P25 control channels are similar, but still have many differences. Don't expect a DMR rest channel to act the same as a P25 control channel.

So to answer your question...it depends on how the system is configured and if there's data only channels involved.

 

[KK6ZTE]

The rest channel should always rotate in Capacity Plus system. New calls start on the existing rest channel, and when a new call starts, a new rest channel is picked and radios not party to that call move to the new channel.

In a Capacity Plus configuration, all the “idle” radios (i.e. radios neither receiving nor transmitting) are on an idle channel called the Rest Channel. Therefore, a new call always starts on the Rest Channel. At the start of a call, the Rest Channel repeater selects one of the idle channels as the new Rest Channel, informs the radios on the current Rest Channel about the new Rest Channel, converts the current Rest Channel to a traffic channel, and starts repeating the bursts sent by the radio. The radios that are not participating in the call (i.e. destination of the call is not of their interest) move to the new Rest Channel.

You can also set a Preference Level to individual repeaters, allowing them to rotate in and out more frequently.

The Capacity Plus system is designed to operate efficiently in a shared channel environment. The term “shared channel environment” is typically used when more than one system uses the same frequency for communication within the same coverage area. For system owners having licenses for shared use of frequencies, it is recommended to set a preference level for the use of a frequency. A repeater whose frequencies have lower interference from other system(s) should be given higher preference level over the repeater whose frequencies have higher interference. Repeaters with the same amount of interference should have the same preference level. For trunking operation, a Capacity Plus system always prefers to use a repeater of a higher preference level over a repeater of lower preference level. For system owners having a mix of shared frequency channel licenses and exclusive frequency licenses, the repeaters with exclusive frequency licenses should have a higher preference level than the repeaters with shared frequency licenses.

I have a frequency at one site very prone to intermod that there's not much we can do about, so it's set to lowest priority (aka the only free channel).

 

[JASII]

Thank you for the reply.

I also was told recently that there can be up to 12 repeaters per site. Does that match what you know, too?

 

[KK6ZTE]

That depends.

For Multi-Site:

Capacity Plus Multi Site supports up to 15 sites with a maximum of 140 peers across all sites
and up to 12 Repeaters (24 logical channels) per site. At any given site, there can be up to eight
Trunking Repeaters (16 logical channels) and up to 11 Data Revert Repeaters (22 logical channels),
however the total number of Trunked Repeaters plus Data Revert Repeaters must not exceed 12. For
example, if there are eight Trunked Repeaters at a site, then up to four Data Revert Repeaters can be
supported at that site.
However, the number of Trunked Repeaters plus the number of Data Revert Repeaters must not
exceed a total of 12. For example, if there are eight Trunked Repeaters at a site, only up to four Data
Revert Repeaters can be supported at that site.

For single site:

From software version R02.30.00 onwards, up to eight Trunked Repeaters (16 logical channels) and twelve Data Revert Repeaters (24 logical channels) are allowed.

Translation: 8 voice repeaters (16 slots/"channels") maximum

 

[JASII]

That depends.

For Multi-Site:

For single site:


Translation: 8 voice repeaters (16 slots/"channels") maximum

This is the system I am interested in. It looks to me like it is a single-site system.

What exactly is a Data Revert Repeater?

ULS License - Industrial/Business Pool, Trunked License - WQLH433 - Communications Management Group, LLC

 

[KK6ZTE]

It's a repeater dedicated to data transmissions (text messaging, GPS, etc) and doesn't carry voice traffic.

 

[JASII]

It's a repeater dedicated to data transmissions (text messaging, GPS, etc) and doesn't carry voice traffic.

That is what I assumed, but you know what happens when you assume!

So, I gather that some repeaters carry data only, then? But others are voice and data, too?

Do end users have just one mobile device for BOTH functions, then?

(Sorry, if this sounds ignorant, but I have a public safety background and our statewide trunked system was voice only. Squads had laptop computers, BUT they used a wireless air card from a cellular for those sorts of things.)

 

[KK6ZTE]

Yes, it's just data for the radios--texting and job ticketing, over the air programming. No MDT-level data (too little bandwidth to be usable). It's just to be able to support large deployments with hundreds of users using all the data applications in the radio.

 

[wtp]

on my county's old analog trunk system i noticed the same thing.
one frequency was not being used.
then one morning there was an accident that tied up a highway so the system lit up.
the only users of that one frequency were the sheriff and EMS/FD.
and even that was sparatic.
with school busses, utilities, animal control, hospitals, and others on and using the system i am sure some got a 'busy' signal.
so it might be a very rare thing, but i am sure it can happen.
we now are on 700 and i hope some of the bugs are out.
PD/FD keying a mic should take priority over some guy gettin his water turned off or a loose dog.

 

[JASII]

Yes, it's just data for the radios--texting and job ticketing, over the air programming. No MDT-level data (too little bandwidth to be usable). It's just to be able to support large deployments with hundreds of users using all the data applications in the radio.

So, will that show up as its own talk group when scanning with a Uniden scanner or will it be ignored, since it is not voice traffic?

 

[KK6ZTE]

So, will that show up as its own talk group when scanning with a Uniden scanner or will it be ignored, since it is not voice traffic?

It shows up as Private Data Calls in my TRBOmonitor application (connected to repeater backend), so I'm sure it would show the same in a scanner (or not at all).