Placer County - P25?

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brumey

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Dec 17, 2005
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Auburn, CA
Hello:
I noticed in the RR database that Placer County have a small trucked system that appears to be for testing. It also seems they simucast the VHF dispatch (west) to this system.

Today I imported the system via Win500 to my Pro-106. I set an LED alert and alarm to notify me if it herd traffic. The LED and Alarm was active a lot but no audio!

I also have a Uniden Home Patrol and noticed the same system was receiving audio okay (not great, just okay).

I looked at the trunking system and noticed the type was set to P25 manual. I changed it to Auto and heard Audio (again, not great quality).

Can someone more familiar with trunking and this system tell me why it imported as manual and why I failed to get Audio that way. Also, why it works in P25 Auto.

I did notice it had a custom table with 6.25 spacing, maybe that is why it imports as manual?

Thanks,

Kevin
(I also posted in the Radio Shack forum but figured local information might be better).
 

mlangeveld

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Jun 29, 2008
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455
Location
Marin County, CA
I suspect that it was imported as a P25 manual system because there is a custom frequency table listed in the database. Because this is a P25 system, it should send the frequency table information over the control channel. I'm not sure why there is a custom frequency table, especially if it is incorrect (i.e. your scanner will not track the system when programmed as P25 manual).

Maybe a DB admin can comment on this?
 

mkewman

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Sacramento County, California
Yes, you need to put in the custom frequency table for it to work. There are currently several Digital simulcasts of Analog Frequencies (CHP, Placer Sheriff, Placer Fire, County Transit, Etc) and a small handful of encrypted channels that are occasionally used by (we think) Radio Techs and perhaps Placer Special Ops officers.

The CHP simulcasts are always going so if you're getting full conversations on those talkgroups, you've got it programmed in correctly.
 

mlangeveld

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Marin County, CA
If you need the custom frequency table, why did it work for him when he programmed it as P25 auto? It did not work for him when he programmed it as P25 manual with the frequency table; is the table correct?

P25 systems usually send out the frequency table information over the control channel, and scanners are able to decode this information automatically. I am not from the area so I am unable to check this system.
 

mkewman

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Sacramento County, California
you know what, disregard my post. I looked at how I'm programmed and I realized that you guys are correct. I HAD programmed the custom table and found it to be incorrect and programmed it as auto. Just a lapse in memory. Disregard my post. Carry on.

*headdesk*
 

mlangeveld

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Jun 29, 2008
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Marin County, CA
you know what, disregard my post. I looked at how I'm programmed and I realized that you guys are correct. I HAD programmed the custom table and found it to be incorrect and programmed it as auto. Just a lapse in memory. Disregard my post. Carry on.

*headdesk*
Thanks for the info. I will update the DB.
 

TrevDog

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Jan 15, 2012
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Location
Foresthill, CA
I'm not sure that any special units use the encrypted channels except for maybe SET. I hear RAT units fairly often on West. My guess would be techs.
 
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