Alabama Interoperable Radio System (was: Alabama First Responder Network)

[jf911]

You got a good source?? I work at Shelby 911

I am hearing both on phase 1
Get a phase 2 scanner in case they do.
Alabaster fire is on fire west .
Just heard alabaster on phase1
My very trustworthy source has started that this will remain a phase 1 system .

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[medic9351301]

7503 lol

 

[jf911]

Haha I know 03 very well

7503 lol

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[medic9351301]

Nough said lol

 

[medic9351301]

Hoover pd talk group

Just curious what talk group does anyone here Hoover pd dispatch on.
Used to hear them on 2703 seems to have changed .

 

[wb4wdu]

Thanks for the information. I know Alabaster is using motorola APX 4000 series radios. I looked up the specs on the set and it said "Phase II capable". What would be the advantage to phase II over phase I ?

 

[medic9351301]

Phase 2 is more spectrally efficient than Phase 1, providing two effective channels per 12.5 kilohertz bandwidth. In P25 Phase 2, each physical base station provides two effective voice channels. It does this by using TDMA, or Time Division Multiple Access, where two independent conversations share the same channel.

So basically the police and fire could use the same talk group and talk at the same time without canceling each other out .

 

[morganAL]

They would not use the same talkgroup. They would/could use the same RF channel at the same time.

For instance... a Phase I trunking site has 6 RF channels. 1 channel is the control channel and the other 5 are working channel and carry the voice traffic. A maximum of 5 simultaneous voice calls are possible at any time. A Phase II trunking site has 6 channels. One control channel and 6 working channels but each channel is TDMA and can carry 2 simultaneous conversations. The site can handle 10 simultaneous conversations if all channels are TDMA.

 

[medic9351301]

Thanks for the update Morgan.
I thank I might have had dmr confused with phase 2.
There is a dmr system in my area .
Where both PD and FD use one freq but on different time slots .

 

[wb4wdu]

Thanks again for explaining the difference in Phase I and II. If I had just read the post a little better and remembered it was TDMA I would have known it can handle more traffic. Thanks again..

 

[codeplug]

Hoover PD Talk Group 2703

Hoover PD Talk Group 2703.
Past few Days Hoover PD Talk Group 2703 has been patched on/off with Talk Group 2591, Unknown User.
All traffic was going out on Talk Group 2591 during the patch.
Any ideas what Talk Group 2591 is or why they are being patched?

 

[ohnofiveoh22]

Hoover PD Talk Group 2703.
Past few Days Hoover PD Talk Group 2703 has been patched on/off with Talk Group 2591, Unknown User.
All traffic was going out on Talk Group 2591 during the patch.
Any ideas what Talk Group 2591 is or why they are being patched?

Hoover has been jumping around. They do have an encrypted 800 tac channel they have been using but they are also using a patch.

 

[jf911]

Possibly using a DE channel for the event involving the protests. I know Hoover, vestavia, Shelby county, mtn Brook, and Homewood pd have been out and about with prosters

Hoover has been jumping around. They do have an encrypted 800 tac channel they have been using but they are also using a patch.

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[morganAL]

Phase I and Phase II

The image attached is a graphical view of Phase I channels vs Phase II channels. The top site is mixed with Phase I & Phase II channels. The bottom site is Phase I only. On the top site, you can see channel 2 & 3 are Phase II. 2/1 indicates channel 2, time slot 1 and 2/2 indicates channel 2, time slot 2. Same with channel 3. Channel 4 is Phase 1 only. Channel 1 is the control channel is always Phase I. The only technical difference in the channels is software licensing. If you have Phase II enabled radios and talkgroups, the two sites shown have the same capacity. If they are Phase I only, then the top site is capable of 3 simultaneous voice calls and the bottom site is capable of 5 simultaneous voice calls. Phase II channels can revert to Phase I if there are no Phase I channels available on the site and the system is provisioned to allow it.

The image is a sterilized screen shot of one of the tools that System Admins have to monitor the system. The white area in the boxes display currently active talkgroup and radio ID or alias.

 

[medic9351301]

Lsm/QPSK

Morgan:
Is there anything that we as scanner users can do to over come this ?
I think I am experiencing this on the new Jefferson country p 25 simulcast site.
When I get a id hit is garbled and drops out .

 

[medic9351301]

Shelby country fire

FYI
Here is a list of the departments assigned to the 4 country fire talk groups.

Shelby co fire west
Alabaster , calera Helena

Shelby co fire north
North Shelby, cahaba valley, Chelsea

South West
Briefeild, county 17, dryvalley,
Indian ford, montevallo, pea ridge,
West Shelby, 1 st battalion.

Shelby fire east.
Columbiana, four mile, harpersville , kingdom, Saginaw, Shelby, summerhill, Vincent, Westover, wilsonville, southeast Shelby

 

[morganAL]

I think you are experiencing TDI.. Time delay interference. All simulcast systems have it, it is the nature of the beast. The engineers can steer it into certain areas based on coverage needs but without seeing the system design maps there is no way to know where it is. Your best bet would be to use a directional antenna with a fair amount of gain and front to back and point it one of the simulcast sites. It may take some experimentation to figure out which one gives you the best performance. For mobile scanning, that is a little tougher. I am pretty sure the JeffCo simulcast is all Phase 1 so I don't think it is a Phase i /Phase II issue.

Morgan:
Is there anything that we as scanner users can do to over come this ?
I think I am experiencing this on the new Jefferson country p 25 simulcast site.
When I get a id hit is garbled and drops out .

 

[medic9351301]

OK I have the issue on the new p25 simulcast site.
The old mix mode system is perfect.
I was told that true p 25 simulcast sites are bad about LSM .

Thanks again

 

[morganAL]

LSM is the modulation type. Linear Simulcast Modulation... I think that is right. One thing Motorola told us to do when setting up radios is the change the modulation. If the radio might ever be used on a simulcast site, they told us to change the modulation type from C4FM to CQPSK. Not sure if scanners have that option though.

 

[medic9351301]

Thanks for your replies and time to help

No they don't.
I had a friend that is far away from the sites.
He told me that he heard it loud and clear on a hand held scanner and a rubber duck. With no problems.
He might be 30 miles from any site .
I am experimenting with different ants.
Got a duck on it right now. Going to try a paper clip next.