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Cleveland Metro Parks Transmissions

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pipes8e

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#1
Have the Cleveland Metro Parks encrypted their transmissions? I'm still figuring out my RS Pro-106, but I'm successfully listening to several other agencies on the Cuyahoga County MARCS system.

When scanning, the scanner will indicate there is a transmission on the Metro Parks frequencies. Most of the time I simply hear a little click, the scanner shows the TG and the frequency, but I don't hear anything else. I occasionally hear a second or two of garbled speech. I checked the control frequencies and they're all programmed in. My scanner software says I've had over 120 hits on the Metro Parks TGs.

I'm in Cleveland Heights but that really shouldn't make a difference, should it?

Thanks for any advice.
- Doug KB8TGT
 
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#2
cleveland metro parks rangers

i have them programed in my GRE-800 scanner and it sucks a lot i don't like the 700 system.
most of the time i can't monitor them its never clear i live in parma and work in cleveland heights my scanner is in the car and when i go over the valley view bridge it works good and 90% of the time its garbled.
 
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#3
Have the Cleveland Metro Parks encrypted their transmissions? I'm still figuring out my RS Pro-106, but I'm successfully listening to several other agencies on the Cuyahoga County MARCS system.

When scanning, the scanner will indicate there is a transmission on the Metro Parks frequencies. Most of the time I simply hear a little click, the scanner shows the TG and the frequency, but I don't hear anything else. I occasionally hear a second or two of garbled speech. I checked the control frequencies and they're all programmed in. My scanner software says I've had over 120 hits on the Metro Parks TGs.

I'm in Cleveland Heights but that really shouldn't make a difference, should it?

Thanks for any advice.
- Doug KB8TGT
There is a sticky at the top of the forum: Ohio MARCS - Project 25 System, which will give you some answers - maybe not the solutions.
 

pipes8e

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#4
Still Searching for Answers

Thanks for the pointer to the MARCS forum. I had already tried with very little luck. I re-read a lot of the stuff just to make sure I didn't miss anything. But, of course, I am relatively new to digital scanning, so I will always be missing a little.

The forum mentioned someone who had good luck listening to the Metroparks. He was near the airport, so I drove there. Wow. Good signal, 80% understandability. I drove around and found the signal quality seemed to vary with my location. But shouldn't this affect All the traffic on MARCS? Not simply one TG?

If I receive some MARCS TGs, why would I not receive other ones? Don't they all use the same system? If I'm only hearing the output signal from MARCS, wouldn't the reception be the same if the original source was 2 miles from me or 11 miles?

Another explanation I ran across was that towers at different distances and confuse the radio because their signals would arrive at slightly different times. If this were the cause of the silence then wouldn't it affect all the TGs on the system?

A friend suggested a better antenna. But, again, if I receive some TGs why would I not receive other ones?

I appreciate the suggestions you guys have provided. I guess I need to do some more research.

Thanks,
Doug KB8TGT
 
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#5
As discussed in the 700 MHz P25 subforum by user unit6817 ....:...."I do pick up Cleve Metroparks garbled as has been discussed, but the Hilllcrest region fire talk group crystal clear. Has to be something with how their equipment is set up"......

I find the same thing. I'm only receiving the Beachwood site and have the 20 db attenuator on using a discone in the attic.

It's a problem with scanners. "Real" radios on the system shouldn't have this problem
 
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#7
I was on Warrensville Center Road today and the Cuyahoga County P25 system was coming in loud and clear in Shaker Heights and Warrensville Heights in my car using a GRE PSR500 with an 800 mhz rubber ducky antenna from Radio Shack. Most of the traffic was from a fire unit with the first digit being 8 which I assume is from the Hillcrest region. Discussion involved whether mutual aid would be needed from Richmond Heights. I may have even picked up some Metro Park Ranger traffic.
I live in Parma Heights and only receive the Metro Park Rangers in a very garbled fashion. I don't quite understand why this Cuyahoga system only seems to work well on the East Side of town. Is the Cuyahoga County Sheriff going to eventually migrate to this system?
 
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#8
As discussed in the 700 MHz P25 subforum by user unit6817 ....:...."I do pick up Cleve Metroparks garbled as has been discussed, but the Hilllcrest region fire talk group crystal clear. Has to be something with how their equipment is set up"......
Cleveland Metroparks appear to be using EF Johnson subscribers, a purchase request was approved for EFJ radios last year: http://www.clemetparks.com/pdf/Board notes/2011/09-08-11 Minutes.pdf

In P25 Phase I operations the newer EF Johnson radios use the AMBE +2 vocoder, Motorola radios and all scanners continue to use the IMBE vocoder. The different vocoders may be the cause of the difficulties receiving Metroparks while other users using Motorola subscribers are received clearly.

https://www.efjohnson.com/resources/dyn/files/171947z8ebcbe0c/_fn/Vocoder_09_09.pdf
 
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#9
I worked for an EFJ dealer/service station 40+ years ago. Their stuff was pretty shakey then. Didn't even know they still made stuff today. A lot of things have changed in that time.

Probably the different structures of vocoders is what we expereience with scanners. Since the EFJ and Batwings TGs probably don't overlap I guess the "real" radios wouldn't notice this? Or maybe they would?
 

budevans

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#10
Cleveland Metroparks appear to be using EF Johnson subscribers, a purchase request was approved for EFJ radios last year: http://www.clemetparks.com/pdf/Board notes/2011/09-08-11 Minutes.pdf

In P25 Phase I operations the newer EF Johnson radios use the AMBE +2 vocoder, Motorola radios and all scanners continue to use the IMBE vocoder. The different vocoders may be the cause of the difficulties receiving Metroparks while other users using Motorola subscribers are received clearly.

https://www.efjohnson.com/resources/dyn/files/171947z8ebcbe0c/_fn/Vocoder_09_09.pdf
The older model Moto radio's used IMBE, current Moto APX radio's are AMBE+2. So it's not an AMBE+2 vocoder issue. It's just the way the Johnson radio's work.
 
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Wirelessly posted (Mozilla/5.0 (Linux; U; Android 2.3.4; en-us; DROID Pro Build/4.5.1-110-VNS-35) AppleWebKit/533.1 (KHTML, like Gecko) Version/4.0 Mobile Safari/533.1)

First all the eastside fire agencies are using XTL/XTS, very few APX radios are in use. Second APX only uses AMBE on phase 2, APX continues to use IMBE with some proprietary noise reduction on phase 1
 

budevans

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#12
Wirelessly posted (Mozilla/5.0 (Linux; U; Android 2.3.4; en-us; DROID Pro Build/4.5.1-110-VNS-35) AppleWebKit/533.1 (KHTML, like Gecko) Version/4.0 Mobile Safari/533.1)

First all the eastside fire agencies are using XTL/XTS, very few APX radios are in use. Second APX only uses AMBE on phase 2, APX continues to use IMBE with some proprietary noise reduction on phase 1
AMBE+2 is just DVSI's latest upgrade to the original IMBE vocoder line. It's fully backwards compatible meeting all original P25 (phase 1) requirements.

Your message seems to imply that the MOTO APX has two vocoders. I've only seen references for the APX with the AMBE+2.

I've heard the APX demo'd on the this system, they had the most natural sound of any of the radio's tested.

Regardless, the Metro Parks radios do sound more garbled than other users on the system.

Ultimately it just comes down to the location based Simulcast Distortion that consumer grade scanners just aren't handling well. I've mentioned on the MARCS P25 forum that I can take my scanner to my sisters house, just a quarter mile from mine and get perfectly clear reception. It's frustrating, but that's what it is.
 
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