Marion County MECA Digtial sytem

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W9NES

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I have a question for anyone who has a Uniden BC 996T in Marion County/Indianapolis ONLY!!!I live on the Northwest Side of Indianapolis around the area of 79Th and Michigan Road and I have been tweeking my Uniden Bc 996T on my nightstand in my bedroom and I have my settings for IMPD at the following levels GAIN is set to +3 and the Gain is also set to +3.I can hear Dispatch and the car back to dispatch but my voice is somewhat garbled.I am getting the control channel with pleanty of signal and that is not the issue.The issue at hand is this and I would like to get some help on what I can do to clear up the voice that is garrbled.I am using a rubber duck antenna with a bnc adapter pluged into the Uniden Bc 996T. I live east of the MECA tower at 7300 Lafayette Road and I also live north of the Tower at Butler University.I am getting all the distrcts for IMPD.Need your ideas on what I can do without adding a outdoor antenna.Thanks For The Help, Tim DeLong W9NES, *Any and all help would be appreceited in my area*
 

rdale

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Need your ideas on what I can do without adding a outdoor antenna.
Try moving it to a different spot in your house, but your best bet is an outdoor unidirectional antenna pointed at the closest tower.
 

Viper43

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Tim,

Over and over and over again, it is location, location, location, and NOT just YOUR location. The system is DIGITAL, it WILL have digital sounds to it, and no matter how hard you try there will be garbled comms from "road units" due to structures that block all or part of a portables transmission (trees, buildings etc), the only fix on the portable side is to move to another location. The ONLY choices you have are to move to another location in the house OR better yet put your tower up that you have at home put an antenna on it and use it.

I get very little garbled comms from the road units, never bad enough now that I can't understand it, even off my 396 with a RS800mhz rubber duck sitting on the desk next to the computer tower. It's not near as good as the discone up on the bent over tower pole or the 800Mhz beam but it's completly readable, even with the roofing and and aluminum sideing. When using the rubber duck on the 396 it is the location that it's at that helps, but when it is on the multicoupler with the other scanners it doesn't matter where it is in the house, it will pull in MECA Digital. Again there is the situation where the location of the officer on the street is makes a difference on whether his side of the comms is garbled or not, and there is nothing you or I can do about that, but we can in most cases help it by having a better listening location or better yet an exterior antenna.

BTW, all settings on my 396, 996 and 600 are default settings with nothing touched to optimize them.

Well i have to go to work.... or should I say the races :)

V
 

jerk

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And this quote for the Wiki "Posted by --Al42 21:06, 14 Sep 2005 (CDT)
Addition by Paul Opitz on 6/7/2007
One other thing to note is that the adjustment mentioned above must be done while you have good reception. The other side of that coin is that the above adjustment does absolutely nothing to fix reception issues. If you have bad decode, first ensure you are actually getting a good signal (no interference and solid receive). You can check this by tuning the frequency conventionally, opening squelch, and listening to see if you are getting dropouts or audible interference. Only after fixing any reception issues (changing antennas, location, etc) should you try to optimize the P25 decode thresholds.

Once optimized for a system, the threshold settings should not be changed, regardless of future interference or signal conditions, unless you have confirmation that the system engineers have actually made changes to the system itself (which is highly unlikely, as it would require all mobile units operating on the system also be brought in for retuning). "


I think your settings are wrong. I keep my settings to zero. (The factory default). When I have used the setting below, it improves slightly. I choose to run the scanner with no tweaking applied, and my reception was fine in Indy on the BCD396. Sound is on par with Hamilton Co. Ohio. Again for that it is on system default setting.

The best settings found by the majority of users on the board here is:
Digital
P25 resp time -7
P25 ref gain +3
I think minimally you need a negative 1, 2, or 3 for resp time. Though -7 seems to be best, another listener to MECA said -4
 
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ten78

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Buy yourself an XTS series radio, and if you have a cop buddy, have him run it up to MECA and have it programmed. You will love it
 

SCPD

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How do I access the P25 Resp time and P25 Rf gain on the 996?


If you have the new firmware have the scanner off then hold the hold botton and turn the scanner on it will flash then push the f botton"scroll Knob" then push in on the volume knob.
 

AK9R

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I am getting the control channel with pleanty of signal and that is not the issue.
The signal strength meter on your scanner is not a reliable indicator of your ability to decode a digital signal.

You live within about five miles of about a dozen analog and digital television transmitters. Anyone of them could be putting out a harmonic or a spur strong enough to overload your scanner. You may have a full-scale signal on your scanner, but that doesn't mean there's enough of a clean digital signal for your scanner to decode.

I live east of the MECA tower at 7300 Lafayette Road and I also live north of the Tower at Butler University.
MECA is a simulcast system. Always has been. When the original analog system was rolled out, there was an atomic time reference located at Willard Park. The signal from that reference was transmitted via microwave around to the various towers. The time reference was used to synchronize the transmitters so users who were equidistant between towers would not experience "heterodyning" between the two signals.

The MECA digital system is also simulcast, but the synchronization of the transmitters is being done using time signals from the GPS satellites. With a digital system, the synchronization of the transmitters is critical. Otherwise, users experience garbled voices. And because you are almost equidistant between two towers, the signals from those two towers are reaching your scanner with just enough offset to cause huge decode problems if the synchronization is not absolutely perfect.

You have a BCD396T, don't you? If so, walk around your neighborhood while monitoring the system. I think you'll find that the coverage in your area is very spotty. Find a location where the system sounds pretty lousy. Move a few feet and see if it sounds better or worse. That's what I experienced when I drove around your part of town yesterday.

It's possible that the Motorola and MECA technicians still have some tweaking to do on the simulcasting. If you can't find a way to improve your reception in the next few days, give it a month and try again. I know that when the SAFE-T tower in Danville was brought on-line, I had trouble receiving it the P25 digital talkgroups. Over time, the reception got much better. No system as complex as these is perfect right out of the box.

Tim, it may seem like I'm giving you a hard time. Maybe I am. But we are all trying to make useful suggestions and trying to help you understand how to improve your reception.
 

W9NES

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Thanks Bob and others for your help.I am just very mad that Cannot get the system when everybody elese is across Marion County/Metro Indianapolis.I will be posting some helpful ideas that I have used and are working for the 996T.
 

W9NES

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Hello To All of you.I received a e-mail from another member who let me know that he set is GRE radio in the FM Mode vs the NFM setting.I have tried this and IT DOES MAKE A DIFFERENCE.My voice has cleared up and I put up a antenna cut for 915Mhz and it has helped.I am now getting the data channel all the time and I am able to hear IMPD Northwest and IFD Fire.I am looking for a notch filter for the 800Mhz band to kill all my inteference form the nearby tv and radio transmittters getting into my scanner.If anyone can post your ideas here that would b great.Thanks Bob for understanding how I am feeling.
 

jwoody062

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Can someone tell if theres anything i can do to help Eliminate the garble sound im getting on some VC channels?I am using psredit500 to program my PSR-600,I have tried moving the radio around the house,i live very close to downtown Indpls and i plan on getting a 5 element yagi antenna,are there any settings i can change in the radio?
 
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Viper43

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Hello To All of you.I received a e-mail from another member who let me know that he set is GRE radio in the FM Mode vs the NFM setting.I have tried this and IT DOES MAKE A DIFFERENCE.My voice has cleared up and I put up a antenna cut for 915Mhz and it has helped.I am now getting the data channel all the time and I am able to hear IMPD Northwest and IFD Fire.I am looking for a notch filter for the 800Mhz band to kill all my inteference form the nearby tv and radio transmittters getting into my scanner.If anyone can post your ideas here that would b great.Thanks Bob for understanding how I am feeling.
I tried this just out of curiosity, it works and it DOESN'T. It only works to improve things IF your set to AUTO, but if you are set to FM or NFM there is no difference in decode quality. I'm guessing it helps in that it's going into the "mode" faster. What surprised me though was there was no difference between FM & NFM at all on either the 996 or the 600. And it doesn't help no matter what you do if your getting more than one tower.

The way I tested this was pretty simple, programming each scanner with 3 duplicate MECA digital systems and setting one to AUTO, one to FM and one to NFM. I tried it at home and as I drove around Indy. Get between two towers and you still get garbled comms, or get a portable that is in a bad location and even dispatch has problems understanding them.

BTW, MECA is still having unit ID issues with incorrectly programmed radio ID's.

V

V
 
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