How many of you are using a BCD996P2 scanner on MPSCS P25 P1 simulcast systems sucessfully?

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Silent Key
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I'm curious of how many people are using a BCD996P2 scanner in Michigan and NOT experiencing simulcast distortion issues?

I've been doing it for years on the Macomb simulcast system at my home in Macomb Township, MI. and it works perfectly. I have a friend in Richmond that does the same.

It's quite common on RR for numerous people to tell others it's impossible to use anything other than the SDS100 & SDS200 scanners. I don't think the results would be the same in a mobile installation, but if you are I'd like to hear from you and what part of Michigan are you in?
 

freqs

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Are you near a Tower there is 9 in the county one on Card in Macomb.
For me here in Warren 11 and Schoenherr my 436 didnt do all that good unless i got closer to a tower .
so i did end up getting the SDS100
 
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btt

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I know it has been talked about it in great detail already in threads on RR, but there still seems to be a lot of misunderstanding on the subject. Simulcast distortion is only a problem if the delay spread from multiple signal sources (or reflections) is significant enough to cause the demod (weather it be old-style 4-level FSK slicer or D-QPSK symbol sync) to be unable to track the phase of the symbols correctly. If you live in an area where one tower dominates over all the other towers, you probably won't have an issue with an old-school receiver. For a more advanced receiver, with D-QPSK demod, a good symbol sync, and RF AGC, the simulcast delay spread will not be an issue for fixed or mobile operation within the area the system was designed for. The delay spread is very carefully planned and compensated for with signal strengths, topography, location,etc... not to mention the synchronization in the time domain. It is amazing that it works, but it does.
 

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Silent Key
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Are you near a Tower there is 9 in the county one on Card in Macomb.
For me here in Warren 11 and Schoenherr my 436 didnt do all that good unless i got closer to a tower .
so i did end up getting the SDS100

Actually I think it's up to 12 towers for Macomb's simulcast frequency now. I'm somewhat surounded by several. I'm at 25 Mile Rd & Romeo Plank Rd. I think the tower on Card Rd is the closest at about 6 miles S-E of me as the crow flies.
 

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I know it has been talked about it in great detail already in threads on RR, but there still seems to be a lot of misunderstanding on the subject. Simulcast distortion is only a problem if the delay spread from multiple signal sources (or reflections) is significant enough to cause the demod (whether it be old-style 4-level FSK slicer or D-QPSK symbol sync) to be unable to track the phase of the symbols correctly. Of course the more advanced QPSK demod is superior. If you live in an area where one tower dominates over all the other towers, you probably won't have an issue with an old-school receiver. For a more advanced receiver, with D-QPSK demod, a good symbol sync, and RF AGC, the simulcast delay spread will not be an issue for fixed or mobile operation within the area the system was designed for. The delay spread is very carefully planned and compensated for with signal strengths, topography, location,etc... not to mention the synchronization in the time domain. It is amazing that it works, but it does.

I know one of the radio techs but haven't seen him in a few years. I recall talking to him when things improved a lot and asked him what happened. I think he mentioned timing and synchronization so you might have hit the nail on the head!
 
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dispatchgeek

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While my explanation pales compared to btt’s above, it certainly all deals with timing and synchronization. The simulcast sites use a Motorola TRAK 9100 time standard. These use GPS and (I believe) a rubidium standard to generate a variety of pulsed outputs to the system components. It’s a rather neat device to read up on.
 
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smithken

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I don't have a 996P2 but I do have a 996T, I don't have any trouble with the Wayne County Simulcast system. I'm also within range of the Northville site so if I do have problems with Wayne County I can just switch over to Northville, Northville is not simulcast.
 

DewAddict

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I don't have a 996P2 but I do have a 996T, I don't have any trouble with the Wayne County Simulcast system. I'm also within range of the Northville site so if I do have problems with Wayne County I can just switch over to Northville, Northville is not simulcast.

When I switched to the Northville site I seemed to lose a lot of traffic (specifically Livonia Fire and some Westland area) that I was receiving on the simulcast towers, do you experience the same? I felt that maybe Northville was not a "neighbor" site and thus not carrying the transmissions.
 

smithken

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When I switched to the Northville site I seemed to lose a lot of traffic (specifically Livonia Fire and some Westland area) that I was receiving on the simulcast towers, do you experience the same? I felt that maybe Northville was not a "neighbor" site and thus not carrying the transmissions.

Before I lost power for 4 days I monitored Livonia Fire Dispatch on both the Wayne County system and Northville and found out you are right, I never heard Livonia on the Northville site. It has been a long time since I tried to listen to the Northville site and I found that I have a hard time receiving it now, my guess is that they have reduced power or they have changed their antenna pattern to be more directional away from Livonia.
 
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