Indianapolis Marion County MECA Settings PRO-197

[matthewpetro]

I recently purchased a PRO-197 Digital Trunking Scanner from Radio Shack. I am having a problem with my program for MECA in Indianapolis. I receive a signal that is VERY broken up. I have Hendricks loaded with NO issues however MECA Indianapolis is causing me the distortion problem and I can’t seem to resolve this issue. Can you please assist? (It will start the dispatch tone then cut out for 3-4 sec then come back for 1-2 sec then repeat the cut out process) That is the best way to explain this issue...

Below are my Settings for the TSYS:

Type: P25 AUTO
Tag: MECA
Frequencies: Ch01: 856.162500
Ch02: 856.512500
Ch03: 857.662500
Ch04: 858.187500
L/Out: Off
Atten: Off
Narrow FM: No
Audioboost: Off
Dwell: 0
DIG AGC: Off
SuperTrack: On
Multi-Site: Off
T Tables: Default

As far as the talkgroup is setup is as follows for all of them but the ID and Tag changes.

TSYS: MECA
ID: 10202
Type: Group
Tag: FD DSP
L/Out: Off
Priority: Off
Delay: On
Delay Time: 20
Audioboost: Off

 

[N9WP]

Hi Matthew, I replied to your email but thought I'd post it here for others and someone else may jump in with some other advise. I am not familiar with the radio shack scanners, however, what you are describing happens with a lot of scanners on the Indianapolis MECA system. MECA is a simulcast system that scanners just don't like. Basically there are transmitting towers all across Marion county. These towers transmit the same thing on the same frequency. What happens is your scanner receives the transmission from tower A but it also receives the same transmission on the same frequency from tower B and maybe a tower C. You are closer to Tower A but because you are a little bit further from Tower B and C, those signals arrive at the scanner at different times. What happens is the scanner can't decode the signal because it's receiving signals at slightly different times, milliseconds apart. So it can't decode the signal.

Another example, if you have someone with a conventanal radio and they transmit on a frequency and then someone else keys up and transmits on that same frequency, you hear garbled transmissions from the scanner. With MECA, the scanner is trying to decode the garbled signal, sometimes it can decode it and sometimes it can't.

The fix for us scanner users is to limit reception from other towers on the MECA system. It's all about the antenna or scanner placement if using the duckie antenna. You could try the Radio Shack 800mhz antenna. This is a great antenna that I use all the time on my handheld. It's not directional but it could help, it's just trial and error. Another thing you could try is getting a 800mhz yagi antenna which is a directional antenna and aim it at one of the towers. I have this at my house (A Wilson 800mhz yagi, about 50 bucks from ebay) and it works great but of course my scanner is tied to the coax cable.

People report these problems all across Marion county so you aren't alone with this. Here is an old thread in the forums section that is pretty long on this same problem: http://forums.radioreference.com/in...-meca-digital-reception-issues-solutions.html

Give that a read and it may help you understand a little better. Someone posted about taking alumanum foil and using that as a shield, I have tried that and it does help but I didn't want that sitting on the end table. Anyway, I don't think there is anything wrong with your settings. It's probably just the way MECA is. But if there is something wrong with your settings, then hopefully someone will jump in and say something. I would suggest making sure something isn't turned on like weather alert which could interupt the transmission every 2 seconds but you say Hendricks county is fine, so I'm 99% sure it's just your location and how MECA is.

 

[matthewpetro]

Brian,

Thank you for your reply. I am wondering would it work to limit to 1 frequency instead of 4 since I am a base station at home. Sould that work or no?

 

[N9WP]

The 4 frequencies you have are possible control channels. Only 1 of them will have the control channel (sounds like a bunch of data, or like an engine noise if you were to listen to it), so you could only have that 1 frequency in your scanner, however, if the control channel changes to one of the other frequencies, you would have to add that frequency. Others have locked out the 3 that aren't active control channels. That may help you lock onto the control channel better but I don't believe it will help with the audio that breaks up. I also don't think the control channel changes frequency so you probably would be safe with just having the 1 frequency in there. Everything is trial and error, never hurts to try new things to see what may work.