Understanding Capacity Plus trunking

[natedawg1604]

Hi,

If you haven't heard any voice call on that frequency, I am pretty sure it's because you are monitoring to the data revert channel of the system. Only data calls can pass on that kind of channel, but it will show what's going on on the voice system, probably to allow the radio which is sending the data to move to the voice channel on a call...


So, you still need to find 2 frequencies to have your system complete

Tikev

Actually I'm starting to suspect the data calls could possibly be mirroring the beginning of voice calls on another seemingly unrelated (i.e. non-linked) Cap+ system, I suppose I should post raw audio files from both systems for others to review. As mentioned above, these 2 systems are NOT linked Cap+ so I'm not sure how they could be connected, if at all.

Regardless if I am missing two frequencies as you suggested, should they be broadcasting on OTA channels 5/6 and 7/8, or could they be sharing OTA channel pairs 1/2 & 3/4? I've logged the system numerous times and thus far I've only seen OTA channels 1-4...

 

[mtindor]

So, I have a question about a somewhat odd Cap+ system. Basically I'm monitoring a single UHF frequency, which registers as Cap+ in DSD+. Notably, I've not found any other frequencies associated with this system. The odd thing is, it appears the system is utilizing 4 system channels on 1 RF frequency. Now, the channel activity screen displays 4 channels active at various times. Unlike other Cap+ systems, when I monitor the one frequency in DSD+ manually, when the rest channel moves between 1/2 and 3/4 in the channel activity window, I continue to see LRRP & ARS messages in the event log, regardless of which channel is active.

As you can see below, this system generates a lot of LRRP & ARS messages. Although it also generates occasional voice headers, I've never heard any audio from the TG's, nor has DSD+ ever generated a per-call audio file from the TG's. (Incidentally, I think this system might be somehow tied-in to another Cap+ system used for voice calls, not really sure though). So, has anyone heard of a Cap+ system using 4 virtual/system channels on a single RF frequency? Here's an except of the event log:



And here's a few excerpts of the terminal log (note the LRRP & ARS messages appear when the Rest Ch. =1, AND 3):



..... [Rest Channel =1]

In DSDPlus Ch=# is a logical channel. Ch 1 and Ch 2 are the timeslots on the frequency you are listening to and Ch 3 and Ch 4 are timeslots on one other frequency. Im pretty sure that's now it is.

I know, you say you haven't foudn any other Cap+ freqs for that Cap+ site, but that doesn't mean there isn't one to be found.

If you Sat on that frequency long enough, DSDPlus (at least latest Fl version) should tell you the LCN of that frequency.

Mike

 

[Jay911]

Hey folks, quick question. Can talkgroups in a Cap+ system be assigned to a specific LCN/LSN like is done in LTR (with "home channels")? I've had a DSD+ instance parked on a particular frequency in a three-frequency Cap+ system during a relatively quiet time of day, when only one agency might be using the system. I see the rest channel intermittently coming to this frequency, but voice calls seem to be steadfastly sticking to a specific other frequency in the system. I have for sure received voice calls on this freq before, so I know it's not a data channel. I'm wondering if the agency that is/was active at that time of day is programmed to only use that one frequency/slot pair.

 

[EricCottrell]

Actually I'm starting to suspect the data calls could possibly be mirroring the beginning of voice calls on another seemingly unrelated (i.e. non-linked) Cap+ system, I suppose I should post raw audio files from both systems for others to review. As mentioned above, these 2 systems are NOT linked Cap+ so I'm not sure how they could be connected, if at all.

Regardless if I am missing two frequencies as you suggested, should they be broadcasting on OTA channels 5/6 and 7/8, or could they be sharing OTA channel pairs 1/2 & 3/4? I've logged the system numerous times and thus far I've only seen OTA channels 1-4...

Hello,

If the status on the data channel reflects the status on the voice channels, then both are part of the same site and you have found the voice channels. The voice channels will be channel pairs 1/2 and 3/4.

Linked Cap+ links sites together, not data channels and voice channels.

73 Eric

 

[natedawg1604]

Hello,

If the status on the data channel reflects the status on the voice channels, then both are part of the same site and you have found the voice channels. The voice channels will be channel pairs 1/2 and 3/4.

Linked Cap+ links sites together, not data channels and voice channels.

73 Eric

Okay, so here is a link to 3 raw audio files of the two systems I referenced above:

https://www.dropbox.com/s/79t05ygwgc1k92u/CC-DSDPlus-Raw-Input_2016-06-27@151433.wav?dl=0

https://www.dropbox.com/s/6kjv0fynyclm6db/VC-DSDPlus-Raw-Input_2016-06-27@151436.wav?dl=0

https://www.dropbox.com/s/ewiy4a59wqlxxwn/DSDPlus#1-Raw-Input_2016-06-27@151432.wav?dl=0

It certainly appears these are two separate but related systems; as you will see one system (file starting with "DSDPlus#1") is a single-frequency Cap+ system with 4 OTA channels, and the other system is a two-freq Cap+ which ALSO uses OTA channels 1/2 and 3/4. The single-frequency system definitely seems to "mirror" the two-frequency system at the start of voice grants, but hopefully the experts here can review the raw files and provide more insight on what's going on.

 

[slicerwizard]

as you will see one system (file starting with "DSDPlus#1") is a single-frequency Cap+ system with 4 OTA channels

It can't be. The channel you were monitoring was announcing a call (TG 1 on ch 3) on slot 2, while slot 1 was broadcasting an LRRP message. The voice call had to be on a second RF channel.


+DMR slot2 BS DATA DCC=1 CSBK Cap+ RestCh=4 ActiveCh:TG=3:1
+DMR slot1 BS DATA DCC=1 Data Header DPF=[2:UcData] Tgt=65535 Src=100 Conf=0 SAP=[4:IP Data] Blocks=6 Pad=10 Last=0 Seq=0
+DMR slot2 BS DATA DCC=1 CSBK Cap+ RestCh=4 ActiveCh:TG=3:1
Cap+ RestCh=4
+DMR slot1 BS DATA DCC=1 Rate 1/2 Data
+DMR slot2 BS DATA DCC=1 CSBK Cap+ RestCh=4 ActiveCh:TG=3:1
+DMR slot1 BS DATA DCC=1 Rate 1/2 Data
+DMR slot2 BS DATA DCC=1 CSBK Cap+ RestCh=4 ActiveCh:TG=3:1
Cap+ RestCh=4
+DMR slot1 BS DATA DCC=1 Rate 1/2 Data
+DMR slot2 BS DATA DCC=1 CSBK Cap+ RestCh=4 ActiveCh:TG=3:1
+DMR slot1 BS DATA DCC=1 Rate 1/2 Data
+DMR slot2 BS DATA DCC=1 CSBK Cap+ RestCh=4 ActiveCh:TG=3:1
Cap+ RestCh=4
+DMR slot1 BS DATA DCC=1 Rate 1/2 Data
+DMR slot2 BS DATA DCC=1 CSBK Cap+ RestCh=4 ActiveCh:TG=3:1
+DMR slot1 BS DATA DCC=1 Rate 1/2 Data LRRP; Tgt=65535 Src=100 39.92757 -105.45501 9mph 212deg


Why are you so adamant that it "is a single-frequency Cap+ system with 4 OTA channels"? Why can't it have two RF channels?


Notably, I've not found any other frequencies associated with this system.

Look harder. Visit the site and find the 3/4 carrier when 1/2 says it's carrying voice traffic.

 

[Voyager]

It's easy to find a rest channel when it's on CH 3 or 4 - just listen to the other licensed frequencies for the burst which happens every couple seconds.

 

[natedawg1604]

It can't be. The channel you were monitoring was announcing a call (TG 1 on ch 3) on slot 2, while slot 1 was broadcasting an LRRP message. The voice call had to be on a second RF channel.


+DMR slot2 BS DATA DCC=1 CSBK Cap+ RestCh=4 ActiveCh:TG=3:1
+DMR slot1 BS DATA DCC=1 Data Header DPF=[2:UcData] Tgt=65535 Src=100 Conf=0 SAP=[4:IP Data] Blocks=6 Pad=10 Last=0 Seq=0
+DMR slot2 BS DATA DCC=1 CSBK Cap+ RestCh=4 ActiveCh:TG=3:1
Cap+ RestCh=4
+DMR slot1 BS DATA DCC=1 Rate 1/2 Data
+DMR slot2 BS DATA DCC=1 CSBK Cap+ RestCh=4 ActiveCh:TG=3:1
+DMR slot1 BS DATA DCC=1 Rate 1/2 Data
+DMR slot2 BS DATA DCC=1 CSBK Cap+ RestCh=4 ActiveCh:TG=3:1
Cap+ RestCh=4
+DMR slot1 BS DATA DCC=1 Rate 1/2 Data
+DMR slot2 BS DATA DCC=1 CSBK Cap+ RestCh=4 ActiveCh:TG=3:1
+DMR slot1 BS DATA DCC=1 Rate 1/2 Data
+DMR slot2 BS DATA DCC=1 CSBK Cap+ RestCh=4 ActiveCh:TG=3:1
Cap+ RestCh=4
+DMR slot1 BS DATA DCC=1 Rate 1/2 Data
+DMR slot2 BS DATA DCC=1 CSBK Cap+ RestCh=4 ActiveCh:TG=3:1
+DMR slot1 BS DATA DCC=1 Rate 1/2 Data LRRP; Tgt=65535 Src=100 39.92757 -105.45501 9mph 212deg


Why are you so adamant that it "is a single-frequency Cap+ system with 4 OTA channels"? Why can't it have two RF channels?


Notably, I've not found any other frequencies associated with this system.

Look harder. Visit the site and find the 3/4 carrier when 1/2 says it's carrying voice traffic.

Did you run the 3 files in 3 instances of DSD+ at the same time (they were recorded simultaneously)? It sure looks like these 2 systems are somehow related, the LRRP announcements have many of the same Radio ID's, and the rest channels seem to rotate at the same time. Regardless I will keep looking for another frequency.

The single frequency I found has not yet broadcast an actual voice grant, that is why I thought it might be a single-frequency system only for data, and it's somehow referencing voice grants on this other system. I suppose the one freq I found could be dedicated solely to data messages and the other missing frequency handles voice grants or something.

 

[CanesFan95]

Here in Tampa, we have a 1-frequency Cap+ system on 462.300 that is the 1/2 channel. But I always get S1 and S2 showing up, even though the rest channel never bumps to anything other than 1/2.

 

[adcockfred]

I am having just about the same problem here in Houston, but with con+ 435 I have a half channel on site 1 and channel 5. And channel 9 and 10 finally came in but jumps to site 2 then back to 1. Have partial audio, Can't get any channel assignments on site 2 on any of the 27 controls frequencies. Also hearing people I know are on 119 and 330

 

[slicerwizard]

Did you run the 3 files in 3 instances of DSD+ at the same time (they were recorded simultaneously)? It sure looks like these 2 systems are somehow related, the LRRP announcements have many of the same Radio ID's, and the rest channels seem to rotate at the same time. Regardless I will keep looking for another frequency.

Since some of the calls in the "CC" and "VC" files are identical (same users saying the same things), they're obviously related.

The single frequency I found has not yet broadcast an actual voice grant, that is why I thought it might be a single-frequency system only for data, and it's somehow referencing voice grants on this other system. I suppose the one freq I found could be dedicated solely to data messages and the other missing frequency handles voice grants or something.

Yes, it's clearly a data channel.

Here in Tampa, we have a 1-frequency Cap+ system on 462.300 that is the 1/2 channel. But I always get S1 and S2 showing up, even though the rest channel never bumps to anything other than 1/2.

The S1/S2 display has been covered in other threads.

 

[natedawg1604]

Since some of the calls in the "CC" and "VC" files are identical (same users saying the same things), they're obviously related....

Just to clarify, the CC and VC files are from a known/confirmed/verified two-frequency Cap+ system. However, it looks like third file from the other system which broadcasts data messages, is somehow related to the two-freq Cap+ system, I was hoping you could run all 3 files simultaneously in 3 instances of DSD+ to look at this...

 

[slicerwizard]

I did (anyone can) and yes, the data channel appears to be related - same two talkgroups in use and same or similar radio IDs.

 

[natedawg1604]

I did (anyone can) and yes, the data channel appears to be related - same two talkgroups in use and same or similar radio IDs.

Thanks, I just wanted someone else to confirm what I though I was seeing. Is it possible the data frequency is somehow symbolically referencing voice calls on this other system, such that there is no second voice frequency?

I'm guessing if there is another frequency, it must be simulcasting the same voice calls broadcast on the other two-freq Cap+ system. In my area there are several Conventional DMR sites linked together simulcasting the same talkgroup, maybe this is a similar type of thing. In any event, usually I'm able to find DMR/Idas/Nexedge freqs pretty easily by running random band-searches on a scanner and/or staring at spectrum for a while in SDR#, so I'm a bit mystified by this.

Perhaps the "missing" freq is broadcasting a weaker signal than the data frequency I found (I kinda doubt it), and/or is masked by a separate & more powerful DMR system on the same freq. situated closer to my monitoring location.

 

[adcockfred]

Something mystifying is going on. The question is how to cyfer it. There seems to be clusters of 4 on the spectrum. I have even tried monitoring the offset. One little trick I have learned. If I populate a good Vc freq in an off site and it comes in on the off site, in Vc window will alternate telling me the good site and the site I am on. Now sometimes I even get voice on the wrong site.

 

[DaveNF2G]

Are there specific instructions for tracking Capacity Plus systems using the latest DSD+ Fast Lane release somewhere in this thread? If so, can somebody tell me which of the now 155 previous messages contains them?

If not, can those directions be found somewhere specific? I'm sure I've seen some, but they are not in the documentation files with DSDPlus and their website contains no usage instructions whatsoever.

 

[slicerwizard]

Are there specific instructions for tracking Capacity Plus systems using the latest DSD+ Fast Lane release somewhere in this thread?

I wouldn't think so, since this isn't a DSD+ thread.

can those directions be found somewhere specific?

Have you tried the instructions that accompany each update?

DSD+ v2.10

Cap+ monitoring
---------------

Follow these steps to monitor / follow the rest channel and voice calls on a Cap+ system

a) select a network ID

Cap+ systems do not broadcast a network ID

If the system has been added to the RadioReference database, use its page number

Otherwise, assign the system a unique NID (9999, for example)

b) create an entry in the DSDPlus.networks file

Example:

Cap+, 9999, "Mayberry PD"

c) if the network has multiple sites, create entries in the DSDPlus.sites file

Example:

Cap+, 9999, 1, "North"
Cap+, 9999, 2, "South"
Cap+, 9999, 3, "East"
Cap+, 9999, 4, "West"

d) for each known system frequency, create a channel record in the DSDPlus.frequencies file

Initially, use invalid channel numbers

Example:

; Mayberry PD North

Cap+, 9999, 1, 99, 450.5000, 0.0, 0
Cap+, 9999, 1, 99, 451.2625, 0.0, 0
Cap+, 9999, 1, 99, 454.9125, 0.0, 0
Cap+, 9999, 1, 99, 455.5000, 0.0, 0

e) tune CC FMPA/FMP24 to an active system channel (note: TCP link required)

CC DSD+ will scan the DSDPlus.frequencies file for a Cap+ record with the same frequency;
The first matching record will be used

CC DSD+ will use the frequency record to establish the system's network ID

CC DSD+ will use the NID to display the network and current site names

f) at some point, DSD+ should determine the channel's ordering
and display it in the event log window

Example:

"450.500000 is first Cap+ repeater (Ch1 and Ch2)"

Use the information to edit the channel's record in the DSDPlus.frequencies file

Note: continue to use invalid channel numbers

Example:

Cap+, 9999, 1, 101, 450.5000, 0.0, 0

g) repeat e) and f) for each active system channel

Example:

"451.262500 is third Cap+ repeater (Ch5 and Ch6)"
"454.912500 is fourth Cap+ repeater (Ch7 and Ch8)"
"455.500000 is second Cap+ repeater (Ch3 and Ch4)"

Cap+, 9999, 1, 101, 450.5000, 0.0, 0
Cap+, 9999, 1, 105, 451.2625, 0.0, 0
Cap+, 9999, 1, 107, 454.9125, 0.0, 0
Cap+, 9999, 1, 103, 455.5000, 0.0, 0

h) when the ordering of all of a site's active channels has been determined,
edit the channel records so they have the correct channel numbers

Example:

Cap+, 9999, 1, 1, 450.5000, 0.0, 0
Cap+, 9999, 1, 3, 455.5000, 0.0, 0
Cap+, 9999, 1, 5, 451.2625, 0.0, 0
Cap+, 9999, 1, 7, 454.9125, 0.0, 0

CC DSD+ will now automatically direct CC FMPA/FMP24 to follow the rest channel
and direct VC FMPA/FMP24 to follow voice calls

i) in the future, to monitor this site, tune CC FMPA/FMP24 to the current rest channel


BTW, I simplify that procedure by just running CC FMPx in normal/manual mode until I've identified all of the channels and their LCNs, and then I flip it to CC/rest following mode. That way, I can skip the "continue to use invalid channel numbers" requirement.

 

[DaveNF2G]

Thanks. I don't know why I couldn't find it. TMI, I guess.

There does need to be a simplified version for those who have already determined the LCN ordering for a system.

 

[DSDPlus]

There does need to be a simplified version for those who have already determined the LCN ordering for a system.

Pick a NID. Add entries to .Networks, .Sites and .Frequencies files. Very similar to Con+ systems. Then tune CC FMPx to current rest channel. CC FMPx must be running in CC/Rest following mode.

 

[CanesFan95]

It's funny how this thread is titled "Understanding Capacity Plus Trunking" and yet I can't understand hardly a word people are saying. The very first post is:

"Hello
In answer to indigo88's post the bit 2 in the CSBKO=62 PDUs refers to the channel in use. So the CSBKO=62 may be being sent on channel 1 but bit 2 tell the radios which channel the voice or data activity is taking place in channel 2. I'm finding the channel number from the CACH.

In addition I can add that bit 7 is only set then nothing is happening."

And then later on, it's:

"Well clearly the "Unknown Full Link Control LC: FLCO=4 + FID=16" messages contain both the Group ID and..."

I'm sorry, I thought this was UNDERSTANDING Capacity Plus? LOL. Meanwhile, I'm sitting here behind the keyboard, like WHAAAATT???