Ongoing Changes: Marion Co. MECA System

[KC9NEG]

Scanner_freak, could you clarify? Based on current knowledge, to you anticipate difficulty monitoring SAFE-T simulcast, new MECA, or both?

Todd/Indy

 

[loumaag]

There are several areas in Indiana where several Project Hoosier SAFE-T sites are tied together in a simulcast fashion (effectively functioning as one site). I've had no trouble monitoring P25 digital modulation on those thus far. Hopefully such will be the case with the MECA upgrade.

Since I am not there in Indiana, could you supply an example of a SAFE-T site that is simulcast? I realize that this is OT a bit, but I was unaware of any SAFE-T sites that were simulcast and beg the participants pardon for delving into this for a moment.

 

[rdale]

Based on current knowledge, to you anticipate difficulty monitoring SAFE-T simulcast, new MECA

I'd bank on new MECA issues like MPSCS simulcasts, but not any Safe-T until they go fully P25.

 

[SCPD]

Since I am not there in Indiana, could you supply an example of a SAFE-T site that is simulcast? I realize that this is OT a bit, but I was unaware of any SAFE-T sites that were simulcast and beg the participants pardon for delving into this for a moment.

Look at the RR DB for Safe T see Boon County Simulcast Indiana

There where some areas that ISP had some trouble so they added a tower and some new freqs to help cover the area

I Have NO troubles listeing to Safe T it is full scale I think it mostly depends on what you are using for a Antenna,Connectors,Feed line Cable ext I do have to say there is a big diffrence in the Hamilton County Area Safe T being a little weaker vs Boone County right next door. As for MECA I dont think any one has to worry about picking it up the signal is much better now with the new Antenna's pending on witch site you leave near and has had some upgrades done However the site 860.7625 CC comes from is still poor compared to the other CC I have heard today sevral times Disp asking for Info repeated.

 

[aaron315]

Since I am not there in Indiana, could you supply an example of a SAFE-T site that is simulcast? I realize that this is OT a bit, but I was unaware of any SAFE-T sites that were simulcast and beg the participants pardon for delving into this for a moment.

Boone Co Listed as Site 121 in the database.
Hendricks Co listed as Site 129 in the DB.
Lake Co listed as Site 207 in the DB.

I monitor the Hendricks Co site daily without problems. I monitor Boone Co as I pass through a couple of times a month. There are some spots where the attenuator helps. I've never been to Lake Co.

396, 996 and XTS 5K

 

[loumaag]

Thanks to both w8fcc and aaron315 for the information. I guess had I looked a little harder at the sites I would have seen the "simulcast" on Boone and Lake Counties. (duh!)

For those of you who are unfamiliar with what the simulcast issue is in regard to digital audio, please take a look at the new Wiki page I just put up called simulcast digital distortion. If you see any errors or omissions, please feel free to correct, but it should give you an overview of what the problem is and some solutions to help you deal with it.

 

[KC9NEG]

Thanks everyone for resurrecting this thread with useful info. Dare a mod sticky it again if we all continue to behave ourselves?

Todd/Indy

 

[ind224]

Meca

When I have had questions about MECA I just call. I'm not with any agency and even had a tour of the center scheduled once but had to cancel due to work obligations.

The folks are really nice on the phone. Honestly, I've had better "customer service" from them than some retail chains.

Just ask for a technician when you call if you have system q's and if you want the tour they will connect you with the PIO.

http://www.indygov.org/eGov/County/MECA/home.htm

I live near the BR/Fairgrounds area so it will be interesting to see the dead spots go away. I can tell you if you park in the Walmart lot at ~ 71st/ Keystone you won't hear much, if anything on the system.

 

[scannerfreak]

I'd bank on new MECA issues like MPSCS simulcasts, but not any Safe-T until they go fully P25.

Rob is right.. If it turns out to be P25 simulcast, which all indications say it will be, the chances of decode problems are 100%. We also do not know the extent MECA plans to use encryption either.

 

[DiGiTaLD]

Boone County Simulcast

Anybody try monitoring the Boone Co. SAFE-T simulcast with a GRE 500 yet? Guess I oughta do that. I'll program it up and have a listen today.

Control is currently on 866.7375 MHz (the alternate). Don't know where you're at, but I'm in NW Johnson County, and I'm able to track it and monitor it fairly well, both analog and digital voice, on both my 96 and 2096 using just 800 MHz rubber ducks. Obviously, some spots are tougher than others, but it still comes through. I'm well outside the intended simulcast "footprint" as well, which I find interesting.

Well, DiGiTaL must be doing all the right things. I have a tremendous amount of problems monitoring the Boone County Simulcast system. All the sites are tied together. I can't pick ANYTHING up on the Boone County tower freq at all. The only traffic I hear, when it does trickle thru, is off the Crawfordsville tower. And even then it seems it's usually medical. I rarely will pick up Boone County Sheriff Dispatch. Even with the scanner in the town of Thorntown, I hear nothing, unlesss it comes over Crawfordsville's tower.

Check to see what control channel you're using. As of now, Site 121 (the Boone County Simulcast towers) are using the alternate control channel listed above.

I monitor the Hendricks Co site daily without problems.

I also have no problems with Site 129 (Hendricks County simulcast towers) but I'm pretty close.

Two completely different set-up's. Motorola P25 simulcast systems use Linear Simulcast Modulation, CQPSK, which is very difficult for the current scanners to decode. Granted, reception is best when inside the coverage "foot print" so those in that area will be better off than those not. But from someone who monitors a P25 CQPSK simulcast system every day, don't get your hopes up

So what you're saying is that there's a difference between the simulcasting of P25 digital voice on a true P25 system (9600 bps control channel) versus simulcast P25 digital voice on a Motorola SmartZone (3600 bps control channel) system?

 

[scannerfreak]

So what you're saying is that there's a difference between the simulcasting of P25 digital voice on a true P25 system (9600 bps control channel) versus simulcast P25 digital voice on a Motorola SmartZone (3600 bps control channel) system?

That is correct. Motorola P25 systems use LSM, which is the 12.5 kHz version of CQPSK. This is extremely difficult for the scanners to decode. You will not see these issues in the current SAFE-T simulcast sites as they do not use LSM . You cannot compare the two For those who have never heard it, Here is what a P25 CC sounds like. This is what you will be listening to hear.

 

[GTO_04]

That is correct. Motorola P25 systems use LSM, which is the 12.5 kHz version of CQPSK. This is extremely difficult for the scanners to decode. You will not see these issues in the current SAFE-T simulcast sites as they do not use LSM . You cannot compare the two For those who have never heard it, Here is what a P25 CC sounds like. This is what you will be listening to hear.

In your opinion which of the handheld digital scanners will do the best decoding with that system? The 396, the Pro-96, or the PSR-500? The reason I ask is that I am considering the purchase of a PSR-500 and right now I am only used to SAFE-T which doesn't use LSM.

GTO_04

 

[DiGiTaLD]

That is correct. Motorola P25 systems use LSM, which is the 12.5 kHz version of CQPSK. This is extremely difficult for the scanners to decode. You will not see these issues in the current SAFE-T simulcast sites as they do not use LSM . You cannot compare the two

Good information. Thanks for the clarification! I have done some monitoring of Illinois Starcom-21, which is a true P25 system with my PRO-96, and had no problems decoding the digital voice, but the site I was listening to was a single site, not multiple sites set up in simulcast fashion. It sounds as though the problem comes up for our scanners when you get true P25 and simulcast together.

 

[scannerfreak]

In your opinion which of the handheld digital scanners will do the best decoding with that system? The 396, the Pro-96, or the PSR-500? The reason I ask is that I am considering the purchase of a PSR-500 and right now I am only used to SAFE-T which doesn't use LSM.

GTO_04

Hands down the PSR-500 and it still has some issues but it is by far the best (I have them all) I have heard on the Cincinnati system, which is LSM CQPSK. Don't hesitate on the 500, it's an amazing scanner once you get the hang of it.

 

[scannerfreak]

Good information. Thanks for the clarification! I have done some monitoring of Illinois Starcom-21, which is a true P25 system with my PRO-96, and had no problems decoding the digital voice, but the site I was listening to was a single site, not multiple sites set up in simulcast fashion. It sounds as though the problem comes up for our scanners when you get true P25 and simulcast together.

NP I should clarify my statement above "Motorola P25 systems" It should have read "Motorola P25 simulcast systems" I accidentally left that part out Non simulcast P25 systems use C4FM.

 

[GTO_04]

Hands down the PSR-500 and it still has some issues but it is by far the best (I have them all) I have heard on the Cincinnati system, which is LSM CQPSK. Don't hesitate on the 500, it's an amazing scanner once you get the hang of it.

Thanks for the feedback! It is very helpful.

Also, I do hope rebanding is part of the upgrade (I think). Sometimes MECA reception is pretty good, at other times it is full of static even at close range. I just wonder if they still aren't having problems with NEXTEL interference.

GTO_04

 

[DiGiTaLD]

Intermod

Sometimes MECA reception is pretty good, at other times it is full of static even at close range. I just wonder if they still aren't having problems with NEXTEL interference.

Most certainly. It affects pretty much anything you listen to on 800 MHz, MECA or otherwise. The intermod from Nextel and cell sites is horrible. Most of the time, though, unless you are right on top of an offending transmitter, the attenuator will make the signal listenable again. Don't expect the digital voice to cure the problem, either. Intermod from strong, nearby cellular and Nextel sites still blows out digital voice to the point where it is unintelligible. I can be within a mile of the local SAFE-T site here in Greenwood, specifically at the intersection of IN-135 and County Line Road, and get blown out by a cellular/Nextel site to the southeast of that intersection, and another to the southwest. The attenuator usually cuts down the interference enough to hear the SAFE-T site again, but its really bad without it.

Even when rebanding happens (don't look for it right away), there will still be some problems with intermod affecting our scanners. They have such wide-open receivers, its bound to happen. Commercial radios, such as the subscriber radios used on the systems, are not as affected nearly as much as our scanners are because their receivers have much better filtering and selectivity when it comes to intermod rejection, etc.

 

[GTO_04]

Most certainly. It affects pretty much anything you listen to on 800 MHz, MECA or otherwise. The intermod from Nextel and cell sites is horrible. Most of the time, though, unless you are right on top of an offending transmitter, the attenuator will make the signal listenable again.

When I switch in my attenuator [396] I don't pick up anything at all on SAFE-T and this is near the intersection of 38th and Meridian. Maybe I have a weak RF circuit.

Don't expect the digital voice to cure the problem, either. Intermod from strong, nearby cellular and Nextel sites still blows out digital voice to the point where it is unintelligible.

Exactly!

So how far behind are they on rebanding, 2 or 3 years?

GTO_04

 

[SCPD]

They are allready Rebanding now look at WQDA709 Howard County has gone rebaned the new freqs are in the 851 to 853 range now and a lot of ISP is now rebanding look under YE and YP codes on the FCC site Public Safety does not have to reband if they opt out they are the only ones who have that choice. Also some of Hancock County has started as well.

As far as MECA they have a site now at 38th and Meridian so there should be no trouble hearing it


Here is a link to some of the info of the 38th Meridian new site pulled up by Microwave but it has the new transmit and recieve there as well

http://wireless2.fcc.gov/UlsApp/ApplicationSearch/applLocSum.jsp?applID=3987884

 

[Viper43]

Also some of Hancock County has started as well.

There is nothing listed for Hancock Co and rebanding. The only recent 800Mhz activity for anything in 800Mhz in Hancock Co. was the recent addition of their own talkaround channels licensed by Hancock Co. which has nothing to do with rebanding or SAFET. These new frequencies are for on scene use and car-car etc.. Hamilton,Henry, Rush and Shelby Co. are the only ones listed around here in YE/YP listings. Unitrunker shows no changes either, and the system is still as unstable as it has been since installation.

V