Some MARCS questions

tweiss3

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I'm new to digital scanning and the Ohio MARCs system. I have an RTL-SDRv3 that I have been able to make operational using DSDPlus Fastlane. I've even managed to get the aliases to work, so I know what I'm listening to, and was able to adjust the priorities.

I want to make sure I'm getting as good of a signal and quality as I can and have a few questions. Some important information. I am in Summit county in the middle of 4 towers. 6.08 miles, 4.04 miles, 2.85 miles and 3.53 miles from the towers. I'm using the "antenna" kit that came with the SDR suction cupped to the window.

1) Is this too close to the towers to get a good signal lock? I had to turn up the gain quite a bit to hear. I also was reading about the Tusc. county guy that was in the middle of the 3 towers that had an issue with the simulcast and signal strength being too great.
2) The attached audio file, is this typical quality/clarity? Even if I were to buy a Uniden scanner (which I am still tempted to do)? (TO BE POSTED AS SOON AS INTERNET COMES BACK UP AT HOME)
3) My rough understanding of MARCS-IP is that I could listen to the entire state (for agencies that have simulcast on) from my office? I was hearing Wayne/Cuyahoga and other county stuff as well, had to really adjust the priority to make sense of what I was hearing.

Thanks,
 

northernsummit

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Tweiss,

I listen to the entire system with four dongles myself using trunk recorder instead of DSDPlus. Since I'm using a splitter to share one antenna with multiple dongles and that splitter was causing loss I built a yagi tuned to the middle of the Summit County system. I live about 3 miles north of the Twinsburg tower and have my yagi pointed directly at the red beacon on that tower.

This helps eliminate simulcast issues because the yagi is narrow and deaf to either the Richfield tower or anything south of here. If you want to improve your signal strength a yagi aimed at the nearest tower (preferably if there isn't another one "behind" it) is, in my opinion, the best option.

3) My rough understanding of MARCS-IP is that I could listen to the entire state (for agencies that have simulcast on) from my office? I was hearing Wayne/Cuyahoga and other county stuff as well, had to really adjust the priority to make sense of what I was hearing.
Summit's system is allowing other agencies to affiliate, so if any one radio from those agencies finds any one summit county tower to be a preferable signal over their home agency either as a result of their normal operating, or because they drove into Summit County, then you're going to hear those talk groups coming out of Summit County's towers (as well as whatever home tower the rest of that agency is on).

If you are listening to just Summit County's control channel and its related voice channels you will only hear talk groups that have at least one radio affiliated to Summit either by the normal course of affiliation, or because some dispatch console somewhere forces a "patch". You will not hear Columbus PD units off the Summit voice channel, unless one of their cars drives up here with their radio on and there isn't anything prohibiting them from affiliating up here that we don't know about (ie: maybe they can only affiliate within their zone, etc).

If you want to compare the quality of the audio you're getting to what Trunk Recorder generates pick any Summit County fire dispatch talk group and compare it in somewhat real time to this feed which is entirely derived from trunk-recorder audio: Summit County Fire and EMS Live Audio Feed
 

mtindor

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You cannot hear the whole state as a general rule. But any time a unit (car / portable) from another county roams within the Summit Simulcast (jail transport is a good example), you'll hear that unit on their talkgroup and, as long as they are within the Simulcast you'll hear all the other traffic on that same talkgroup. So it is not unusual to hear conversations from out of the county. This is not unique to the simulcast but is more prevalent when monitoring a simulcast since the simulcast is typically covering a whole county.

If you are using DSDPlus with FMP24, TCP-linked together, you will not / should not have any issues whatsoever copying any traffic on the simulcast. It works perfectly. Of course, you should make sure that your FMP bandwidth is set at 12.5 when monitoring the control channel, as that is the preferred filter with for P25 simulcast.

You should watch the display in FMP24. It's fairly easy to tell when you need gain or have added too much gain. When you add too much gain, you will end up overloading the dongle (esp in Summit Co) receiver and you'll see all sorts of spurious signals pop up. Just use as much gain as you need. If you are within the simulcast, you shouldn't need much of an antenna at all -- The antenna that came with the dongle should be just fine. Of course, if you are using a portable/ducky antenna in your house, it is susceptible to picking up a lot of interference from electronics inside the house. I'd guess that you probably should be able to monitor the simulcast with a gain of 30 or so without any issue, maybe even less.. If you hvae to crank the gain up much higher than that, something is likely wrong (probably interference).
 

WX4JCW

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think of it as a cell phone, if a radio tuned to talk group A registers to Site A if you are monitoring site A you can hear it, if a radio is on Talkgroup A But say affiliated (registered) to site B or say Site C you can monitor Talkgroup A on those sites, not all talk groups are active on all sites
 

tweiss3

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Thanks for the answers. I was seeing some odd TGs pop up GC Rail Control, GC RTA Yard, Cleveland Metro LifeFlight Dispatch, Warrensville Heights Fire Dispatch, Warrensville Heights Police Ch 1, stuff out of Chagrin Valley, etc.....

This link is the typical audio I am getting, Google Drive Audio. Is this typical?
 

northernsummit

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Thanks for the answers. I was seeing some odd TGs pop up GC Rail Control, GC RTA Yard, Cleveland Metro LifeFlight Dispatch, Warrensville Heights Fire Dispatch, Warrensville Heights Police Ch 1, stuff out of Chagrin Valley, etc.....

This link is the typical audio I am getting, Google Drive Audio. Is this typical?
Not in my experience, but others have produced DSD audio that wasn't bad to me either. I wasn't a fan of DSDPlus and when I found trunk-recorder I never looked back. Are you still using virtual audio cables to get the audio from A to B?

Click on the feed link above and you'll hear what trunk-recorder off the same exact towers sounds like.

What you're seeing is Cuyahoga County units affiliating to probably the Twinsburg tower. I watch the control channel pretty regularly and see every surrounding county almost all day. Kent PD, Stark SO, Medina, Aurora PD, Streetsboro FIre, etc. They all end up affiliating on and off and it's how the system is meant to work. As long as all of that affiliation use isn't causing a capacity issue in Summit County (I rarely see them get to what appears to be 50% utilization) it shouldn't be a bad thing since it means the system is adapting to the needs of the users. If you don't want to hear it, block the talk groups and just listen to that which interests you.
 

tweiss3

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I'm still using a single dongle with the FMP24 and 1R and the "virtural cables".

I'm love to tinker, and these programs and tweaking give me something to do besides watch TickTock after the kids go to bed. I just did some minor tinkering and adjustments, so I will let it warm up and check quality when I get home. I may also look into trunk-recorder.

I am still tempted to get a 996P2 and justify the cost by saying it has the automated weather alerts.

I should add, I'm running all this on my home workstation (Windows 10 Pro, i9-9900, 64GB ram, Quadro P620).
 

northernsummit

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I am still tempted to get a 996P2 and justify the cost by saying it has the automated weather alerts.
You don't need P2 around here unless you want to listen to some of the stuff on the Parma system (Medina), so if you're going to go 996 you can buy a used 996T or XT and save a bit of money. If I bought a new radio right now it'd be an SDS200.

The weather feature in my opinion is a distraction. But yourself an actual dedicated NOAA weather radio that takes AA backup batteries. If you keep playing with SDR you'll find that the beauty of listening to slightly delayed radio transmissions is that you never miss anything, you just hear it a few seconds later than it happened. With a scanner you get to hear one single talk group and anything said at hte same moment in time is lost. I listen to almost everything via SDR now and throw a radio on when something big is going on and I want to hear it more realtime.
 

mtindor

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I'm still using a single dongle with the FMP24 and 1R and the "virtural cables".

I'm love to tinker, and these programs and tweaking give me something to do besides watch TickTock after the kids go to bed. I just did some minor tinkering and adjustments, so I will let it warm up and check quality when I get home. I may also look into trunk-recorder.

I am still tempted to get a 996P2 and justify the cost by saying it has the automated weather alerts.

I should add, I'm running all this on my home workstation (Windows 10 Pro, i9-9900, 64GB ram, Quadro P620).
Are you using DSDPlus Fastlane or the free version 1.01 from half a decade ago? If you're using FastLane, why not use TCP linking and do away with virtual cables altogether? In fact, in order to properly monitor simulcast systems you need to be running FMP24 + DSDPlus TCP-linked together.

I actually thought you're audio clip sounded pretty good.

Mike
 

northernsummit

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That would probably sound much better. I always felt the reason DSD sounded strange was because of VAC. Not that it sounded bad, but when I first played with DSD it was a lesser quality decode than trunk-recorder's native decode results. I'm as a linux guy, so I love that my entire monitoring solution is out of site, out of mind down in the basement not consuming a Windows machine's entire CPU :)

Are you using DSDPlus Fastlane or the free version 1.01 from half a decade ago? If you're using FastLane, why not use TCP linking and do away with virtual cables altogether? In fact, in order to properly monitor simulcast systems you need to be running FMP24 + DSDPlus TCP-linked together.

I actually thought you're audio clip sounded pretty good.

Mike
 

mtindor

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That would probably sound much better. I always felt the reason DSD sounded strange was because of VAC. Not that it sounded bad, but when I first played with DSD it was a lesser quality decode than trunk-recorder's native decode results. I'm as a linux guy, so I love that my entire monitoring solution is out of site, out of mind down in the basement not consuming a Windows machine's entire CPU :)
I'm a LInux guy too. I like/use Trunk Recorder. It's currently being used to send two BCFY calls sites. But for logging / keeping data, I much prefer DSDPlus or Unitrunker. So my third feed to BCFY Calls is running on SDRTrunk (which does a great job too) and I'm using that Windows machine also to run a copy of Unitrunker and a copy of DSDPlus that are just monitoring the current CC of the feed.

The audio from DSDPlus and Trunk-Recorder do sound different, but I don't have any problem with either one. DSDplus decoded audio seems less bass-y.

I like the out-of-site stuff. I like RPI4s and Odroid N2s for that. But damn they barely can handle an Airspy @ 10msps with T-R.

Mike
 

northernsummit

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I'm a LInux guy too. I like/use Trunk Recorder. It's currently being used to send two BCFY calls sites. But for logging / keeping data, I much prefer DSDPlus or Unitrunker. So my third feed to BCFY Calls is running on SDRTrunk (which does a great job too) and I'm using that Windows machine also to run a copy of Unitrunker and a copy of DSDPlus that are just monitoring the current CC of the feed.
The nice thing about trunk-recorder is you can trigger a script from it and do whatever you want with the control channel data, and since you could just build a pi to listen to that one channel you can build a lightweight logger.

I have TR telling me if radios show up on a talk group I've never seen before (with a deep link to the trunk-player page so I can play the recordings). I have some logic watching for radio affiliations to interop talk groups, and if it sees a spike of affiliations in a short period of time, it notifies me to go pay attention and tells me what agencies are going there because it knows what talk group the RIDs just came from.

Since I can run all the control channel stuff into a perl/python/shell script and do whatever I want with it I effectively have a state engine of the entire system (Which radios are on, which are off, who is on what talk group right now, where a RID was last seen, etc.) in a live database. As long as I don't restart trunk-recorder I'm eventually 100% accurate to the current state of the system, can see how many "foreign" radios are affiliated, etc. It required a small tweak to the trunk-recorder code but I've been talking about submitting it to the core code for awhile now and need to get it done.

You can also make nifty little websites with the data like http://northernsummit.org/SummitP25/ (This was more useful when I was trying to see when someone moved from the old system to the MARCS site). I couldn't easily do any of that with Unitrunker.
 

tweiss3

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Are you using DSDPlus Fastlane or the free version 1.01 from half a decade ago? If you're using FastLane, why not use TCP linking and do away with virtual cables altogether? In fact, in order to properly monitor simulcast systems you need to be running FMP24 + DSDPlus TCP-linked together.

I actually thought you're audio clip sounded pretty good.

Mike
What am I missing. I setup FMP24, the OH file, 1B and the .groups file. Maybe it's TCP linked?
 

mtindor

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What am I missing. I setup FMP24, the OH file, 1B and the .groups file. Maybe it's TCP linked?
Are you using Fast Lane or the free version? If Fast Lane, are you on one of the latest versions? I don't think you can TCP link and handle simulcast on the free version (1.01 from the dsdplus.com website).

I run fmp24 with the -o20001 option. When FMP24 is fired up I make sure BW is set to 12.5 (by hittin the 'b' key when focus is on the FMP24 window. Then I fire up DSDPlus (Fast Lane -- latest version) and select Input --> TCP Linking and Control --> Combined CC/VC Monitor .

Mike
 

tweiss3

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Are you using Fast Lane or the free version? If Fast Lane, are you on one of the latest versions? I don't think you can TCP link and handle simulcast on the free version (1.01 from the dsdplus.com website).

I run fmp24 with the -o20001 option. When FMP24 is fired up I make sure BW is set to 12.5 (by hittin the 'b' key when focus is on the FMP24 window. Then I fire up DSDPlus (Fast Lane -- latest version) and select Input --> TCP Linking and Control --> Combined CC/VC Monitor .

Mike
I am on the current Fastalane. I believe I have those options chosen too.

I am trying SDR trunk tonight, which supports simulcast, and with a few antenna adjustments, its working MUCH better. Listen to this.
 

mtindor

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I am on the current Fastalane. I believe I have those options chosen too.

I am trying SDR trunk tonight, which supports simulcast, and with a few antenna adjustments, its working MUCH better. Listen to this.
If you have those options chosen, you don't need any virtual audio cables.

I have to admit, the SDRtrunk adudio sounds better than the DSDPlus audio. Glad SDRTrunk is working for you. But there could be various reasons why DSDPlus might not decode the system as well as SDRTrunk -- it's all about settings (and how much you fudged around with them in DSDPlus). As a general rule, DSDPlus has no issues copying simulcast systems when TCP-linking is used. The SDRTrunk audio clearly decoded better, and thus sounds better to the ear.

Mike
 

k8zgw

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Just to get my $0.02 in here.
I listen to the Summit system from the Twinsburg tower and the Cleveland system from
I think the "main" transmitter at Orange ( 271 and Chagrin ).
The scanner is an "older" GRE PSR-600.
I have discovered that there is such a thing as "to much' antenna.
My antenna is an old HT BNC antenna ( a 6 inch piece of speedometer cable) on a
magnetic BNC base, magnet'ed to an old Altoids can on the window sill.
I am about 4 miles ESE of "northernsummit", but he is about 300 feet higher.
 
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