SDRTrunk Sdrtrunk and teardown

[Clats97]

Hello, after I figured out how to use Sdrtrunk and became more educated on the matter, I decided to create 2 calls nodes (one for each site), and 1 feed to fill a void in my areas BCFY feeds. Everything has been smooth sailing, but recently ive been running into problems after playing around with different settings. So I have a few questions:

1. What is the difference between selecting "control" & "control & alternates" & "selected" & "all" when it comes to site configuration? What is the best way to configure this?

2. What is the difference between "single" & "for each frequency" when it comes to "configurations" and what is the best way to configure this?

3. Why am i experiencing "teardown" all of a sudden? I do know the definition of teardown, but i do not understand why multiple channels are saying this as the status.

4. Is it possible i am experiencing this because i maxed out the possible calls per channel at 50? (even though this wasnt a problem at all initially, from the get-go when i first started using sdrtrunk was to configure it at the max of 50). WHat is the optimal setting for this?

5. What are the optimal settings for the best possible trunktracking and results? Whats the best maximum calls per channel, and what is the best configuration settings, for example but not limited to the "frequency rotation"? By default the value is 400, but i was advised to set it at 1200?

6. Are there any other tips, tricks, or ways of confuguring sdrtrunk so that it is running optimally, picking up as many calls as possible, and all that stuff that you guys may have to offer?

I am running windows 11 home, up to date, and i have an intel core i5 2.00ghz 8 core processor with a 1TB SSD and 24gb RAM. I am using 3 Noolec Nesdr Smartee SDR dongles, 1 of which is tied up decoding POCSAG pages, and the other 2 i have for SDRTrunk. I was advised that if you run multiple dongles, that sdrtrunk will use the other one if nessecary such as maximum bandwith exceeded or stuff like that? Is this true?

Sorry for asking questions that seem to be elementary in nature, when it comes to scanning and radio I have much, much more knowledge about commercial scanners as i do with SDRs and software programs. I want my feed to be the best as possible and i want it configured for optimal reception and such. I have a Tram 1411 discone antenna, but have noticed no differerence when I switched to a RaTLsnake M6 antenna which is apparently tuned for 800mhz+ which is what my system is on, so i switched the discone back to one of my scanners monitoring my provinces Fleetnet system. The system my sdr dongles and sdrtrunk are monitoring is an APCO P25 Phase 1 & Phase 2 system with some AES256 encrypted talkgroups.

Any help would be greatly appreciated! Thanks in advance

 

[DSheirer]

Short on time, but some answers are here ... User's Manual: Playlist Editor

 

[Clats97]

I should also note that the channel marked as the control channel sometimes switches to idle and stays there for quite a mile. Any ideas on that?

 

[ChrisABQ]

Calls per channel set at 50? My P25 system has 7 voice frequencies (1 channel for each frequency) so it's set at 7. Set at 7, it would decode up to 14 transmissions at once because there are 2 slots per channel/frequency (0 & 1). How many frequencies are in the system you're monitoring?

 

[maus92]

Try changing the 50 to 5. There may be times when two / both RTL-SDR type devices are busy thus not available for assignment to a traffic channel, depending on the frequency spread of the system. A 2 GHz CPU might be challenged to run a resource intensive program like SDRTrunk. You may do better with DSD+ FL. Depending on where the system is being monitored from and whether the system is designed for mobile, portable on-street, or enhanced indoors coverage, your antenna selection may not make much difference. My office is located within the coverage footprint of two simulcast systems, thus reception is rock solid with a simple stock SDR antenna stuck to a indoor railing.

 

[Whiskey3JMC]

I should also note that the channel marked as the control channel sometimes switches to idle and stays there for quite a mile. Any ideas on that?

Do you have all possible control and alternate CCs added to your playlist? CC could have certainly changed & if you don't have it programmed in then it will stay at IDLE until the CC(s) you have programmed become active again.


If you're certain you have all CCs/ACCs programmed in then the next thing I'd suspect is a weak decode. How far away is(are) the site(s) you're trying to bring in? What's your noise floor look like relative to the received signal?

 

[Clats97]

Calls per channel set at 50? My P25 system has 7 voice frequencies (1 channel for each frequency) so it's set at 7. Set at 7, it would decode up to 14 transmissions at once because there are 2 slots per channel/frequency (0 & 1). How many frequencies are in the system you're monitoring?

14. So I should set it at 14?

 

[maus92]

14. So I should set it at 14?

No. Think about the channel loading that you typically see, aka how many talk paths are typically in use at any point in time, and how many of those are carrying unencrypted traffic. If this is the Ottawa P25 system, you will not need 14; probably less that half of that. Start with a lower number, then increase if you are missing traffic. I'm also curious how you have configured SDRT to monitor the two sites that comprise the system. Is this an overlay system (where two sites cover the same geographic area) or do the two sites cover different parts of the service area? Typically, you only need to monitor one site - ideally the one with the better signal / closer to the receiving station.

 

[Clats97]

No. Think about the channel loading that you typically see, aka how many talk paths are typically in use at any point in time, and how many of those are carrying unencrypted traffic. If this is the Ottawa P25 system, you will not need 14; probably less that half of that. Start with a lower number, then increase if you are missing traffic. I'm also curious how you have configured SDRT to monitor the two sites that comprise the system. Is this an overlay system (where two sites cover the same geographic area) or do the two sites cover different parts of the service area? Typically, you only need to monitor one site - ideally the one with the better signal / closer to the receiving station.

Okay thank you. Do you have an opinion on the frequency interval? It's at 400 but I was told you should put It to 1200

 

[maus92]

AFAIK, this is a Motorola system that should not be regularly changing control channels. But lengthening the interval to 1200ms is not a bad idea, It may take a few seconds longer to find the active control channel, but That probably won’t be an issue.

 

[Clats97]

AFAIK, this is a Motorola system that should not be regularly changing control channels. But lengthening the interval to 1200ms is not a bad idea, It may take a few seconds longer to find the active control channel, but That probably won’t be an issue.

I believe that Motorola is the hardware supplier and implements everything but it's not SmartZone II, it's APCO P25 P1 & P2 Common Air Interface. The encrypted talkgroups are on P2 with AES256 on the voice and DES 56 on the data. Here's a link to my feed, in the notes I included all the details from the lisencing data and what's in the RR database.

City of Ottawa Public Works Live Audio Feed

City of Ottawa Public Works Live Audio Feed on Broadcastify.com

m.broadcastify.com

Do you have any tips or tricks for best settings and do you have any answers to my specific questions?

Thanks in advance!

 

[Clats97]

Try changing the 50 to 5. There may be times when two / both RTL-SDR type devices are busy thus not available for assignment to a traffic channel, depending on the frequency spread of the system. A 2 GHz CPU might be challenged to run a resource intensive program like SDRTrunk. You may do better with DSD+ FL. Depending on where the system is being monitored from and whether the system is designed for mobile, portable on-street, or enhanced indoors coverage, your antenna selection may not make much difference. My office is located within the coverage footprint of two simulcast systems, thus reception is rock solid with a simple stock SDR antenna stuck to a indoor railing.

Wow a 24gb ram i7 2ghz isn't enough to run sdrtrunk? I know my computer isn't some amazing gaming computer, but at the same time it's not the bottom of the barrel cheapest option, I assumed it was middle of the range. And I've never had issues even when running resource intensive programs. However, you are right in that when I open task manager sdrtrunk is using about 20-25% of my RAM and is marked as resource intensive. That's why I put PDW, SDR++ and other apps into efficiency mode, to save computing power for sdrtrunk

 

[maus92]

I can answer your specific questions when you provide screenshots of your configuration.

 

[Clats97]

I can answer your specific questions when you provide screenshots of your configuration.

Sure, what parts of sdrtrunk would you like to see?

 

[maus92]

To start (this is version 0.6 Alpha 6):

 

[maus92]

Then, this view (make sure the CONTROL line is highlighted):

 

[maus92]

Finally, (Now Playing, Channel tab):

 

[Clats97]

Finally, (Now Playing, Channel tab):

View attachment 143723

Here you go

 

[maus92]

The very first thing I see is you have set Site 1 as C4FM. This modulation mode is used for single transmit sites. It is more likely that Site 1 and Site 2 are simulcast sites (typically used in urban / suburban areas), thus modulation should be set to LSM.

Site 2 is only reporting 2 control channels 867.8375 (Primary) and 867.4625 (Secondary). I would only configure those 2 channels for Site 2, so remove 866.3375 from your configuration for Site 2.

I suspect that Site 1 uses 866.8875 as its Primary control channel, and 866.6375 as its Secondary control channel, but you have not included a screenshot of Site 1's Now Playing - Details tab. I would delete 866.1375 for now. Bear in mind that we *could* add the third control channel for both sites back in later if necessary.

Please only start Site 2 for now after making the above changes and see how that runs. Post a screenshot of Now Playing - Details tab once you have it running.

 

[Clats97]

The very first thing I see is you have set Site 1 as C4FM. This modulation mode is used for single transmit sites. It is more likely that Site 1 and Site 2 are simulcast sites (typically used in urban / suburban areas), thus modulation should be set to LSM.

Site 2 is only reporting 2 control channels 867.8375 (Primary) and 867.4625 (Secondary). I would only configure those 2 channels for Site 2, so remove 866.3375 from your configuration for Site 2.

I suspect that Site 1 uses 866.8875 as its Primary control channel, and 866.6375 as its Secondary control channel, but you have not included a screenshot of Site 1's Now Playing - Details tab. I would delete 866.1375 for now. Bear in mind that we *could* add the third control channel for both sites back in later if necessary.

Please only start Site 2 for now after making the above changes and see how that runs. Post a screenshot of Now Playing - Details tab once you have it running.

So here's the thing no we do not have simulcast but we have 2 sites... 2 sites and site 1 has 1 control channel and site 2 has 1 control and 2 alt control channels. If I select the alts, it brings me to a P25 decoder page and there's no traffic at all. Currently I just have the sites control channels and it's working fine now but I wanna know why I get teardown.