SDS100/SDS200: Not receiving sheriff in one county

Mongoosmike

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I have three counties in my profile, San Mateo, Contra Costa, and Alameda, Calif. In Contra Costa I have not heard any call from the Sheriff Dept at all, but Fire and EMS calls come through. It is on a P25 system or regionalsystem. I seem to have all the channel listings for Sheriff, and various transponders and such un avoided. I am including my profile file that will hopefully help with the issue. The other counties work very good.
 

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n1chu

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It looks like Contra Costa Sheriff Dept. Is a TDMA Phase 2 (P2) system for their two dispatch TG’s. If your scanner is not P2 capable then it might explain why you can’t hear them. I did not check the other two counties to see if they were also TDMA P2 for the Sheriff’s depts. look at the mode for the other counties and compare. Also be advised a P2 system is capable of receiving both FDMA & TDMA, meaning if your scanner is not a P2, it would still receive those transmissions that are using FDMA. It could be the sheriffs depts in those other counties still use FDMA and your scanner would hear them. It would help if you told us what scanner you are using.
 

Mongoosmike

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Hi and thank you for your help. I have the Uniden SDS-100 hand held so it is capable of the P2 systems.
I had to get it since my R/S PRO-92 was not receiving any channels in the P2 system channels since it had the older technology trunking. The only other small proglem that I have come across is that Fire Dept and EMS channels on the P2 system all come in slightly garbled, slightly muffled and similar to tuning into a SSB channel but they are intelligible and I can make them out. Although the sheriff dept in San Mateo and Contra Costa and Alameda County, which are all on the same P2 system, are totally clear as a bell. This is rather confusing. A friend that worked in the Foster City/San Mateo Consoldated Fire Dept asked if all the channels were like that or just a few, as he was thinking that it could be they were using a private com system they have for special calls and would be scrambled or masked in a way not to be received, but it isn't like that since all the channels are just muffled and garbled, and I can understand the information, so we kind of ruled the private com theory out. Thank you again for all your help.
 

Mongoosmike

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Thank you for the information, and I would not know of any way I could tell if they were encrypted. I read somewhere that an E should be showing somewhere in the frequency listings. Thank you again for your help.
 

n1chu

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The E you refer to is shown in the Mode column if encryption is available for that system. Most understand the E to mean the agency is using encryption. The SDS100/200 will ignore encrypted signals and continue scanning for most of the common forms of encryption. If you click on the heading a pop-up will tell you what each letter stands for.
 

Mongoosmike

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I looked at the frequency listings and there are no type showing as E, or DE, TE
The first law dispatch is showing BM, and the next three law dispatch are showing as RM.
I haven't seen info about the two types you that you mentioned, but I was aware of the type E as being encrypted.
That is why I was confused as to why it isn't working, but the only other thing that I can think of is ithat I set the channels in this listing to avoid since I thought they only pertained to the jail system and not sheriff dispatch. I will unvoid those first 4 frequencies and reload the software to the scanner and see if that theory works. Thank you very much for the info and help again.
 

n1chu

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Ok. If you click on the mode column in the RR Database you will see an explanation of what each letter designates… the DE is two, the D stands for something probably digital and the E stands for encryption. A lower case e stands for encryption either part time on the entire system/dept or just certain units within a TG.
 

Mongoosmike

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Thank you for the descriptions, but I don't need to click on any of them, as I mentioned before, since none of them say E, DE or TE. So they are pretty obviously not encrypted. will have to upload the scanner file to the database then go in and make the selections in Sentinel and open up law 1, 2, 3 and 4 to see if that is the reason for not getting the sheriff calls. When I see prisons listed, and it says N, S, E, W I wouldn't think those would be active police dispatch frequencies. on the prison channels. Thanks again and I will post again when I open up those 4 frequencies. Will keep fingers crossed. ☺
 

Mongoosmike

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Thank you for that info, and that is possible that no one has flagged the channels as encoded yet. It does take a while for that to be noticed and submitted. I will update the software and then upload the scanner to the computer, then remove the avoid for those four frequencies and when I visit friends in San Ramon on Friday, I will see if I hear any Sheriff calls. One thing I have not seen in other frequencies in the other counties is where 'prison' is listed under law dispatch or tac channels, they ahve shown law, then prison descriptions seperately. in the past I have been editiing out different frequencies by looking at the main descriptions and not always checking the end column where it says law, tac 1 and so on. I am hoping that just adding these channes to scan will be the the solution, instead of them actually being encrypted now. Thank you again foor the help and hopefully I will have good news Friday.
 

sallen07

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I looked at the frequency listings and there are no type showing as E, or DE, TE
The first law dispatch is showing BM, and the next three law dispatch are showing as RM.

OK I'm not from the area so I can only go by what is in the database, but I don't believe you are looking in the correct place, and may or may not have programmed things correctly to listen to the Contra Costa County Sheriff.

Is this where you looked?


If so, couple things. The "Type" column doesn't tell you if a frequency has encryption; that would be the "Mode" column, which would say P25E if it were a conventional (non-trunked) P25 channel with encryption.

More importantly though, if you look on that page right above the table where you found "BM" and "RM" you will see a link to this system:


It would appear that the sheriff's department uses that system, and the frequencies you were looking at are used by the court house only.

The good news is that if you scroll down to the "Contra Costa County Sheriff" section and look at the "Mode" column it appears that while there are three talkgroups that are listed as encrypted, most traffic (including dispatch) is in the clear.

Alameda County appears to use the same P25 system as Contra Costa, while San Mateo has it's own.

Do you have that system programmed into your scanner? If so, do you have the Contra Costa Sheriff Talkgroups programmed?
 

Mongoosmike

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I am not sure how to program talkgroups into the scanner, but San Mateo also has talkgroups as far as I know, and I receive all the sheriff, PD and fire with no problems
I went to the Contra Costa county section, with the Calif map on the left side, and just below that on the first listing it says Contra Costa County, then below says Sheriff. then court security channels
I scroll down below that and ther is NO listing that says Contra Costa County Sheriff. Only listings below show all the individual cities, fire dispatch, BART Also, these listings just show the type, mode and tags of the listings, and no sheriff listings, other than the prison listings at the top under law tac. I am primarily only interested in San Ramon when visiting my friends, and Dublin where I travel through when going to or leaving, and Dublin is under Alameda County. I wish there was a away that someone could look at my profile that I sent earlier and edit it or tell me whiat I need to un-avoid. I appreciate everyone's help and patience with this.
 

hiegtx

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I am not sure how to program talkgroups into the scanner, but San Mateo also has talkgroups as far as I know, and I receive all the sheriff, PD and fire with no problems
I went to the Contra Costa county section, with the Calif map on the left side, and just below that on the first listing it says Contra Costa County, then below says Sheriff. then court security channels
I scroll down below that and ther is NO listing that says Contra Costa County Sheriff. Only listings below show all the individual cities, fire dispatch, BART Also, these listings just show the type, mode and tags of the listings, and no sheriff listings, other than the prison listings at the top under law tac. I am primarily only interested in San Ramon when visiting my friends, and Dublin where I travel through when going to or leaving, and Dublin is under Alameda County. I wish there was a away that someone could look at my profile that I sent earlier and edit it or tell me whiat I need to un-avoid. I appreciate everyone's help and patience with this.
1675140892582.png
That note under the Sheriff header is indicating that the Sheriff's Office is not using conventional frequencies. Instead, they are using that linked trunked system:

These are the talkgroups listed:
1675141335805.png
Looking at your file, you do not show Contra Costa at all. Nor do you have Alameda unless those counties are in separate Favorites lists that you did not attach in your first post in this thread.

You can easily either, or both, if these counties using Sentinel.

Go to the database section in Sentinel
Click on USA to expand the list of states.
Next, click on California to expand the list of Counties.
Scroll down to Contra Costa, and expand it.
Click on the County Systems folder:
1675142639870.png
The Contra Costa in the right side pane has the conventional frequencies shown on the county's database page.

If you select Contra Costa and,right><click. on it, you'll get a pop-up menu where you can select to Append it to either an existing Favorites list, or create a new one,
1675143008865.png
Similarly, if you select the East Bay system & <right><click. on it, you can append it to a list as well.
1675143148101.png
Both Costa Contra and Alameda Counties have talkgroups on the East Bay system.

If you also wanted the conventional channels for Alameda, click on that county, then on the County Systems folder to get a list of systems in that county. The entry Alameda is the one you would want to append.

If you append all of these, you'll likely end up with things you do not want. Those can be deleted either the Favorites list editor, or by right=clicking on them in the main Sentinel window & choosing the option to Remove from Favorites list
 

n1chu

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Two questions for you… first, have you ever PREVIOUSLY heard comms on the system your original post stated you weren’t? (You may have answered that in this continuing thread but in the interest of brevity-I’m a but pressed for time presently, I haven’t reviewed the entire thread.) If you have not previously heard what you say you are now not hearing it may be the sheriff’s dept uses another county’s dispatch TG
 

n1chu

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Sorry, I hit send before I finished… I continue here… A possible reason for not hearing anything could be no one has submitted to RR a complete listing of all TG’s assigned to the sheriff’s dept in a county. In which case you can do a search while listening to the sheriffs dept in that county and see if your scanner finds additional TG’s assigned to the sheriffs dept. (If we, the users don’t submit, or the admins at RR haven’t explored or updated their DB, the TG won’t be shown. If you do a search and discover other TG’s that are not listed in RR, monitoring those newly found TG’s may give you an indication they are in fact a dispatch TG, your knowledge of the type of traffic one would hear on a dispatch TG should give you a clue. Secondly, a search of FCC records (which takes some detective work) may show what’s missing, if anything, on the RR database. I would look for the system’s FCC listings for the anything that may distinguish the known dispatch TG’s on those county’s you can hear and see if there is anything that may be comparable on the county you can not hear… doubtful that would help but when all else fails… I’d post (or ask an admin to move this thread) to the Calif regional forum and see if there are some locals that are knowledgeable on the subject.
 

gmclam

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The SDS scanner is the way to go for what you want to monitor. I must wonder what antenna you're using? I have mine connected to an outdoor antenna (whether at home or mobile) and it makes a world of difference. When we were listening to analog signals, we could hear interference. Now that we hear a decoded digital signal, the cause of an imperfect signal is not obvious.

A note about trunking. Typically, each transmission is assigned a different frequency. You can watch the display to see what frequency you are actually receiving the voice traffic on. Up on the tower where the signals originate, on frequency's antenna might be pointed toward you while the next one is pointing the other direction. If receiving from the rubber stock antenna, you should be able to see how this can be problematic.

I'll also note that I pick up the Coco/Alameda system from here in Sacramento county quite clearly. San Mateo is beyond my horizon.
 
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