DSDPlus Why isn't the control channel displayed?

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W4KRR

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Why is the current control channel not being displayed? This is a DMR Tier III system. The control channel is 453.5625. The program has been running, correctly, for several hours. The control channel is listed in the DSDPlus.frequencies file, with the correct OTA channel number. But it shows a "?" in place of the control channel.

1691012550929.png
 

mwjones

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It has been my experience that DSDPlus will show the CC with an unknown Channel ID because that Channel ID is not sent over the air. Once a transmission hits the other timeslot on the same frequency as the control channel, DSDPlus will figure it out and display correctly.

If the System is not using that second Timeslot until all the others are in use, it may take a while to get it to show correctly. If they are using round-robin (which my local Tier III system does) it can happen pretty quickly.
 

W4KRR

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I could be wrong, but I don't think the other time slot of the control channel is used for voice. In SDRTrunk, it shows both time slots as the control channel.
 

mwjones

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Here's a screen shot of my currently running DSDPlus instance:

Screenshot 2023-08-02 171506.png

464.0 has the Control Channel in Time Slot 1, and Time Slot 2 is used for voice (and I see that usage in the logs).

The problem is without knowing how the system administrator configured the system, we're just guessing here. Yes, there is the possibility that they have reserved that second time slot for data or LRRP data, but that wouldn't align with what I've seen on a number of systems.
 

W4KRR

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Here's a screen shot of my currently running DSDPlus instance:

View attachment 146312

464.0 has the Control Channel in Time Slot 1, and Time Slot 2 is used for voice (and I see that usage in the logs).

The problem is without knowing how the system administrator configured the system, we're just guessing here. Yes, there is the possibility that they have reserved that second time slot for data or LRRP data, but that wouldn't align with what I've seen on a number of systems.
Correct; I don't know how this system is configured. I'll have to do some more checking of the logs.
 

sonm10

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Does the site have neighbors? An adjacent neighboring site will show the correct channel ID on the neighbor/peer list.
 

mwjones

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Does the site have neighbors? An adjacent neighboring site will show the correct channel ID on the neighbor/peer list.
That is not always the case. The system I showed the screenshot of above is a Hytera system, and when the neighbor list shows, all 6 neighbors show with the same channel ID on each (and none are valid based on the bandplan). Even the system clock that it shows is off (it reports UTC, which is fine, but the hours and minutes are still way off). The only way I got the right channel ID for all frequencies was to run them through the DMR TIII LSN/LCN frequency calculator to reverse calculate the bandplan.
 

W4KRR

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Does the site have neighbors? An adjacent neighboring site will show the correct channel ID on the neighbor/peer list.
Yes, and all the neighbor sites show their correct site numbers, as well as the OTA channel numbers and frequencies. This is a Motorola Tier III system.
 

sonm10

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Yes, and all the neighbor sites show their correct site numbers, as well as the OTA channel numbers and frequencies. This is a Motorola Tier III system.
Correct, you will have to drive to an adjacent site and get it's neighbor list and the channel ID for the site you're interested in.

You have to reverse the process.
 

dave3825

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Why is the current control channel not being displayed? This is a DMR Tier III system.



DSDPlus notes.txt said :
For some NEXEDGE and Tier III control channels, DSD+ will automatically start trunk tracking.

For most NEXEDGE and Tier III systems and for all Capacity Plus and Connect Plus systems,
accurate channel data for the site being monitored has to be added to the DSDPlus.frequencies
file to enable trunk tracking.

Does that system fall under "Some NEXEDGE and Tier III" or "Most NEXEDGE and Tier III" ?
If most, is your freqs file set up properly?

If the active cc is 453.5625, does it roll to the other cc listed in the database, which is also not being shown in your pic?


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W4KRR

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I have all of the channel ID's, the LCN's, etc. This is not an issue, never has been. The system tracks properly.
On this particular site, the control channel was always 460.550 and never changed. A few days ago it changed to 453.5625. That's not the issue either. The issue is that the control channel, whatever it happens to be at the time, is not showing in DSD+, instead it shows as a "?". I wondered why, and it seems the explanation given in post #2 might be the most likely.
 

cg

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When the control channel changes and the program goes looking for an active one, the Channel Activity window resets and will have to find the active channels again. So unless the CC second slot is seen on the new channel, it will show the ? again and the previous CC will appear as a voice channel (unless the change was due to a failure).
 

W4KRR

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On this particular system, the control channel always shows as "?". If the control channel changes (almost never), the program will not search for lost control channels, even though I have that option checked. This is not an issue with other non Tier III systems.
 

cg

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If it doesn't search for the new CC with the option checked, there may be an issue with the .frequencies file or with the ID not matching up between Network, Sites, and frequencies file. I disconnected the antenna on a couple local DMR systems and it always goes into search. It takes about 10 seconds to start but then scans based on the dwell time. If you have a weaker signal, you may need to increase the time.
 

dave3825

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If it doesn't search for the new CC with the option checked, there may be an issue with the .frequencies file

So does that system rely on the data in the freqs file or does it get everything OTA? Are alt cc used as voice on tier III? If so, kinda strange when one cc is showing with a ?, and the the other cc is not listed at all..

If not OTA, I would look at the freqs file again. If not OTA, do you need to specify the channel number for each slot?
 

W4KRR

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Solved, I think.
I use two dongles for monitoring, one for the control channel, the other for voice traffic. If I change the program to "Combined CC/VC Monitor", using just one dongle, it will then show the control channel properly. Something about using two dongles screws something up.

Also, as CG said in post #16, if I disconnect the antenna, it will search for the control channel. If I just manually change the control channel to something incorrect, it won't search at all.
 

dave3825

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if I disconnect the antenna, it will search for the control channel. If I just manually change the control channel to something incorrect, it won't search at all.
If you want, you could take a raw sample and send it to the DSDPlus. Maybe its a bug.
 

cg

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Makes sense, using a single SDR, it will see the second slot and then show the frequency. With two, it never sees it on the CC SDR. The second Channel activity window would likely show 2 slots for all channels except the one with the CC, it would only show the voice slot.

chris
 
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