Ottawa County Simulcast Problems

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jchulski19

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I'm using 2 SDR's to pick up the Ottawa County simulcast but i'm having some problems. The control channel and all the voice frequencies are full of static. I can pick up Grand Rapids tower without any static at all. Does this have something to do with the QWPSK modulation? or would it be mainly related to the antennas being inside of my apartment? I'm having a real issue trying to figure this out. When the Allendale tower was live I was picking that up just fine as well. As far as I know the main tower on the Ottawa County simulcast is the old Allendale MPSCS tower, correct me if i'm wrong.

Does anybody have any suggestion or comments to add to this
 

BSchaner

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I am not having any static issues. What I believe you are hearing is the VHF side from the radios since it is being patched to the 800mhz system. I do hear static on transmissions which are definitely from the patch. The other talkgroups such as Allegan county and the State Police are coming in crystal clear, that is because they are completely on the system as apposed to a patch from VHF.
 

jchulski19

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Well actually what's happening is I can get the digital signal to decode but it's garbly and Skippy if that makes any sense. What I mean by static is the control channel has allot of static on the digital signal not in the decoded voice
 

BSchaner

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Hmm. Not sure then. I don’t have any issues on the digital side. I didn’t mention though that I’m using a unication G4, so I’m not sure if that could be a simulcast decoding issue.


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jchulski19

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I'm starting to think it may just be an Ottawa county thing. State police comes in fine, and allegan all come in fine on the simulcast towers it's just Ottawa county that is choppy
 

cagosti

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If you are not in the simulcast design footprint you will get phase nulls and timing errors.
 

manlius

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Ottawa’s VHF system is inherently noisy. I have been using a Bendix King portable and a Motorola GM300 on their system since 1993. During this “patch” phase of transition I’ve been listening to the BK on the VHF side and my SDS100 on the Simulcast system. When you hear a noisy transmission on their Simulcast net, you are really hearing the noise and static from the VHF side being digitally encoded and decoded by the Simulcast system and your receiver. Once they are done with the patch, it will sound no different than Allegan, State or any other native P25 system.


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jchulski19

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Ottawa’s VHF system is inherently noisy. I have been using a Bendix King portable and a Motorola GM300 on their system since 1993. During this “patch” phase of transition I’ve been listening to the BK on the VHF side and my SDS100 on the Simulcast system. When you hear a noisy transmission on their Simulcast net, you are really hearing the noise and static from the VHF side being digitally encoded and decoded by the Simulcast system and your receiver. Once they are done with the patch, it will sound no different than Allegan, State or any other native P25 system.


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Except the problem I'm hearing isn't in the voice it's in the raw digital data straight from the discriminator not in the decoded voice I'm not sure if I'm making sense here. I have a radio listening to the raw channel and using software to decode the data. What I'm hearing is static before it even makes it to the decoding software
 

manlius

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Except the problem I'm hearing isn't in the voice it's in the raw digital data straight from the discriminator not in the decoded voice I'm not sure if I'm making sense here. I have a radio listening to the raw channel and using software to decode the data. What I'm hearing is static before it even makes it to the decoding software



That’s above my pay grade.


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kc8bdk

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there is a noticeable difference in the sound of the data stream between simulcast and stand alone

when we changed in Macomb County I noticed the difference right away... that may be what you are hearing

its the difference between C4FM (stand alone) and CQPSK (simulcast) that you are hearing
 

jchulski19

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there is a noticeable difference in the sound of the data stream between simulcast and stand alone

when we changed in Macomb County I noticed the difference right away... that may be what you are hearing

its the difference between C4FM (stand alone) and CQPSK (simulcast) that you are hearing

Ok thanks you understand what I'm driving at lol. Now how do I improve the signal and does the qwpsk affect the ability to decode voice? Because when I listen to the stand alone I can decode the voice from the data stream fine but when I try to decode voice from the simulacast stream everything is all garbled. I mean some voice comes thru just fine but a good majority of everything on that site is garbled. Could it also be that this particular site isn't live yet?
 

kc8bdk

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Ok thanks you understand what I'm driving at lol. Now how do I improve the signal and does the qwpsk affect the ability to decode voice? Because when I listen to the stand alone I can decode the voice from the data stream fine but when I try to decode voice from the simulacast stream everything is all garbled. I mean some voice comes thru just fine but a good majority of everything on that site is garbled. Could it also be that this particular site isn't live yet?

Its not the format that causes the issues... its the multi-path signal reception that causes the breakup

what is happening is you are getting 2 or 3 received signals at the same time... the scanner cant decide which one to chose so they mix together. on the radios the receivers are tighter and the tolerances are higher to clear up the noise

on a scanner, it cannot filter our the multiple streams being received at once. there can be missed calls or choppy traffic. My Pro96 missed a lot of calls. Newer scanners are better

I have not worked with any SDR units... but.. you could try adding the attenuation on the receive side... an inside antenna if you are on an outdoor antenna... a directional antenna pointed toward the closest tower... if you have a preamp multi-coupler... try turning down the gain

not live... after they turn on the sites.. there are some adjustments... but.. mostly audio levels and voting settings. not likely the RF side... there is a chance.. but the levels are pretty close to set when they flip the switch
 

BSchaner

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Well its been awhile and I haven't heard anything from my sources. Does anyone have some information on whats going on, if they are building a tower in Jenison?
 

manlius

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Latest word on Ottawa County is that the transition date is now February 4 and will be for all portable radios. Unknown if/how they cured the Jenison issue or how fast the mobile radios will be rolled out.


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manlius

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Now the “new” changeover date is reportedly March 4. Not sure if the delay is still due to the coverage issue in Georgetown.


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jchulski19

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the changover date is whenever they get the mobiles installed. They did not get the coverage issues worked out and there are for plans to get them worked out they are just gonna deal with it
 
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