SDR on Miami-Dade P25 system
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scanster305
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Meanwhile the post I made with the suggestion for hardware/software, which actually answered the original question, goes ignored.
My apologies. I definitely appreciated that input. I just hope it will work on the Miami Dade P25 system, which is one of the largest in the country and very difficult to get clearly from many areas.
I am currently running SDR in all 3 SE Florida Counties. You will definitely be happy with the results. I sent you a PM with some info ....
Jason
Jason
Signal-Zero is 100% correct on Miami Gardens PD. Their Dispatch channel is encrypted and has been so since the inception of this system. And as was mentioned, Medley and Miami Springs are also encrypted. I believe South Miami and Pinecrest may have also decided to do the same.
Additionally, all of Miami Dade’s districts have three channels assigned, Dispatch, Car and Tac. While all Dispatch and Car channels are in the clear, each district’s Tac channel is encrypted. There are also many other channels that are encrypted such as Warrants, SRT, Info, PolTac, etc.
scanster305
Member
That may all be true. All I know is that I can hear plenty of goings on of Miami Gardens PD often.
Harris’ flavor of LSM looks like crap on a scope. My GRE and PSR are deaf on it for the most part unless I find that one little sweet spot. Move an inch and I’ll lose the CC. My G5 doesn’t miss a beat. I can pick it up all the way up the turnpike to the Sawgrass, sitting in the cup holder, with its factory stubby. You should expect the same with SDR. I’ve heard great reports of the Uniden’s SDS on the system as well and crappy reports of everything else like the HP and 4/536.
Sent from my iPhone using Tapatalk
Sent from my iPhone using Tapatalk
scanster305
Member
I have a PSR-500 that does a decent job but loses plenty and my 436 has pretty much the same “performance”
Ezra
Member
I did try the following setup using Unitracker/RTL-SDR/DSD+:
Link to single dongle trunking setup
And I really didn't have any better luck than with my 436HP. The reception, dropouts, decoding was about the same and it was unusable. Only about 20% of the conversations are understandable. I also tried the setup on Miami PD and it was not as good as the 436 HP so I'm guessing the RTL-SDR receiver quality is not great. Perhaps with a better receiver the solution may work.
This is with the standard whip antenna.
Now with my 12db 824-960 MHz yagi pointed from Miami beach to downtown they both work just fine. Without the yagi the simulcast trips it up, but with the yagi I can get a good enough clean single site signal. Of course that's a lousy mobile solution but if you have a base station I would suggest the yagi. works like a champ. I also used a smaller 6db yagi and that worked fine as well. I just got the 12db to see if it worked better and it does.
Link to Yagi on Amazon
Link to single dongle trunking setup
And I really didn't have any better luck than with my 436HP. The reception, dropouts, decoding was about the same and it was unusable. Only about 20% of the conversations are understandable. I also tried the setup on Miami PD and it was not as good as the 436 HP so I'm guessing the RTL-SDR receiver quality is not great. Perhaps with a better receiver the solution may work.
This is with the standard whip antenna.
Now with my 12db 824-960 MHz yagi pointed from Miami beach to downtown they both work just fine. Without the yagi the simulcast trips it up, but with the yagi I can get a good enough clean single site signal. Of course that's a lousy mobile solution but if you have a base station I would suggest the yagi. works like a champ. I also used a smaller 6db yagi and that worked fine as well. I just got the 12db to see if it worked better and it does.
Link to Yagi on Amazon
Last edited:
scanster305
Member
Super helpful. TY!
Note that most recent versions of DSD+ Fast Lane were specifically coded to work extremely well decoding P25 simulcast modulation (LSM, CQPSK, H-DQPSK, etc.), and is much better than older methods of decoding such as @Ezra is using with Unitrunker in the mix.
There is no reason to be using any other software such as Unitrunker or SDR# at this point if you're wanting to listen to P25 Phase 1 or Phase 2, as DSD+ Fast Lane will accomplish it with just a single dongle. A dongle and DSD+ Fast Lane is all you need, keep it simple.
I'd also point out that there is nothing special about this Miami-Dade system. There are systems much larger than it, including many statewide systems, and simulcasting is nothing new. Many of these P25 systems have simulcast cells made up of a dozen or more physical sites, and they are all tough to decode without the proper hardware/software.
There is no reason to be using any other software such as Unitrunker or SDR# at this point if you're wanting to listen to P25 Phase 1 or Phase 2, as DSD+ Fast Lane will accomplish it with just a single dongle. A dongle and DSD+ Fast Lane is all you need, keep it simple.
I'd also point out that there is nothing special about this Miami-Dade system. There are systems much larger than it, including many statewide systems, and simulcasting is nothing new. Many of these P25 systems have simulcast cells made up of a dozen or more physical sites, and they are all tough to decode without the proper hardware/software.
gcopter1
Member
I used to live on MGPD jurisdiction, Riviera Park (a mobile home park), on the western end of the Intracoastal station.
Believe you me, what you think is MGPD, is not, they're 100% encrypted. When there where calls for police, Miami Gardens is the one who showed up.
However, around NW47th Ave, is back again to either Intracoastal or MIAMI LAKES (aren't you confusing one with the other?).
East of that, and I'm not sure how far east, is Intracoastal for sure.
Before incorporating, they used to be Carol City, as such, Intracoastal fell within their jurisdiction.
Next time you hear something you think is MGPD in the clear, note the TG # and look at the list here on RR. If you can't find it, I guarantee you will, under the Intracoastal TG's.
scanster305
Member
Note that most recent versions of DSD+ Fast Lane were specifically coded to work extremely well decoding P25 simulcast modulation (LSM, CQPSK, H-DQPSK, etc.), and is much better than older methods of decoding such as @Ezra is using with Unitrunker in the mix.
There is no reason to be using any other software such as Unitrunker or SDR# at this point if you're wanting to listen to P25 Phase 1 or Phase 2, as DSD+ Fast Lane will accomplish it with just a single dongle. A dongle and DSD+ Fast Lane is all you need, keep it simple.
I'd also point out that there is nothing special about this Miami-Dade system. There are systems much larger than it, including many statewide systems, and simulcasting is nothing new. Many of these P25 systems have simulcast cells made up of a dozen or more physical sites, and they are all tough to decode without the proper hardware/software.
Thank you for this excellent input. Can you recommend a particular dongle?
scanster305
Member
I’m pretty certain I’ve heard “Miami Gardens 50” I could be wrong of course but I’m pretty sure I have
gcopter1
Member
Yup, like SignalZero said, Miami gardens 50 is their dispatch talking to STA6 MDPD in the clear. TG15028 is MDPD STA 6.
When MGPD needs to coordinate with MDPD, MGPD comes up on their TG as MG 50.
Can't remember if there was ever a time both MG and MDPD were patched in the clear though.
But, MGPD have their own TG's and are 99% if not 100% encrypted.
When MGPD needs to coordinate with MDPD, MGPD comes up on their TG as MG 50.
Can't remember if there was ever a time both MG and MDPD were patched in the clear though.
But, MGPD have their own TG's and are 99% if not 100% encrypted.
Check my previous post SDR on Miami-Dade P25 system
scanster305
Member
Ezra
Member
I forgot... also if you are going the Yagi route with a 436/536 set the site digital threshold to "manual" and threshold level to "5" and set the ATT to"on"
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