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LTR question (& Open Sky and P25)


Septa3371CSX1
 

That sounds like LSM issues.  Most P25 simulcast systems use CQPSK modulation which means the signal is sent from multiple towers a fraction of a second apart.  Most scanners have trouble putting the bits back together since they're only built to handle C3FM modulation which is used by most P25 conventional repeaters and stand alone trunking sites.  If you were to try out a Unication pager, a commercial grade radio programmed for receive only, or a Uniden SDS100/200 scanner - all of which can handle LSM - you'd likely get better results and not have to be in a specific spot.  

Joe Butler 


-----Original Message-----
From: Jeff Kenyon <jkenyon7@...>
To: main@scanner.groups.io
Sent: Wed, Jun 3, 2020 11:30 pm
Subject: Re: [Scanner] LTR question (& Open Sky)

When I replied to this thread a while ago I forgot to mention that when that all went on line I would go DownTown all the time to volunteer and brought a long my Pro-96 and the results were similar to what I was hearing at home.  The nearest site for the Detroit MPSCS is at Denby High School, and I at first thought this wouldn’t be a problem.  However, the first day it came on I was at my grandmother’s house on Moross and I had to precisely point the radio, or else is wouldn’t do so well.


On Jun 3, 2020, at 11:12 PM, Septa3371CSX1 via groups.io <Septa3371CSX1@...> wrote:


Most newer systems are designed to contain the signal in the intended coverage area. This sounds like how the Detroit simulcast on the MPSCS is setup.
Joe Butler
Sent from AOL Mobile Mail



On Wednesday, June 3, 2020 Dennis <main@Scanner.groups.io> wrote:

Regarding the Detroit system, when Detroit joined the MPSCS (statewide system) it used towers from the old system and used or replaced antennas that would direct the signal into the city thus poor reception outside the city.  Remains the same today.

Dennis


Jeff Kenyon
 

It is,, and since my BCD436HP has done a good job in many places I have been here in Rochester with the trunked system, which is Monroe County is nothing but simulcast systems I would be interested to see how it would work on the Detroit MPSCS from where I used to live in Grosse Pointe.


On Jun 4, 2020, at 10:07 AM, Septa3371CSX1 via groups.io <Septa3371CSX1@...> wrote:


That sounds like LSM issues.  Most P25 simulcast systems use CQPSK modulation which means the signal is sent from multiple towers a fraction of a second apart.  Most scanners have trouble putting the bits back together since they're only built to handle C3FM modulation which is used by most P25 conventional repeaters and stand alone trunking sites.  If you were to try out a Unication pager, a commercial grade radio programmed for receive only, or a Uniden SDS100/200 scanner - all of which can handle LSM - you'd likely get better results and not have to be in a specific spot.  

Joe Butler 


-----Original Message-----
From: Jeff Kenyon <jkenyon7@...>
To: main@scanner.groups.io
Sent: Wed, Jun 3, 2020 11:30 pm
Subject: Re: [Scanner] LTR question (& Open Sky)

When I replied to this thread a while ago I forgot to mention that when that all went on line I would go DownTown all the time to volunteer and brought a long my Pro-96 and the results were similar to what I was hearing at home.  The nearest site for the Detroit MPSCS is at Denby High School, and I at first thought this wouldn’t be a problem.  However, the first day it came on I was at my grandmother’s house on Moross and I had to precisely point the radio, or else is wouldn’t do so well.


On Jun 3, 2020, at 11:12 PM, Septa3371CSX1 via groups.io <Septa3371CSX1@...> wrote:


Most newer systems are designed to contain the signal in the intended coverage area. This sounds like how the Detroit simulcast on the MPSCS is setup.
Joe Butler
Sent from AOL Mobile Mail



On Wednesday, June 3, 2020 Dennis <main@Scanner.groups.io> wrote:

Regarding the Detroit system, when Detroit joined the MPSCS (statewide system) it used towers from the old system and used or replaced antennas that would direct the signal into the city thus poor reception outside the city.  Remains the same today.

Dennis