SDS Questions

[shansmi]

First - what is the max signal these devices can handle? In another thread I hooked up an amplified antenna to my SDS200. Seems to be working great. For the most part I see signal levels in the -80dBm range but every so often I see one dip down to -48dBm. Now on the SDS100 I am using the REM820s or the REM842s antennas. I see the same levels at times. My guess is the receivers are capable of much more than -40dBm but just checking. I see nothing in the tech specs for this...

Second - I have several things added as favorites. For the most part I see the LEAs use the different talk groups with one exception. The Sheriff's Dept in the area dispatches for several smaller municipalities. Each has their own Law Talk group. I never see these get used. I see the SD switching between other talk groups just not the ones for smaller cities. This means one of 2 things: either I have something wrong or they are not taking very many calls for these small cities. I have camped on the SD and see the same thing as an open area scan.

 

[W5ATX]

I've only seen -45dB on my sds scanners and that was sitting under a tower, maybe -40, but i'm not certain.

austin police has a bunch of talk channels that i've never seen activity on. it's possible it's encrypted and your scanner is skipping over it. and if you havent already, make sure your scanner is ID Searching and not ID scanning, i've seen typos in the database, example TGID 1243 Sheriff Ch.2 when it was TGID 1234. In ID search mode you'll discover new TGID's that aren't yet in the database. Lastly, you can check broadcastify calls to see if there are TGID's in your area, and with a subscription you can go and listen in on recorded audio on other TGIDs, and even track UID's to see if a sheriff switches channels, and what TGID they are going to. Just throwing some stuff out there, i'm relearning all of this myself, best of luck!

 

[shansmi]

I've only seen -45dB on my sds scanners and that was sitting under a tower, maybe -40, but i'm not certain.

austin police has a bunch of talk channels that i've never seen activity on. it's possible it's encrypted and your scanner is skipping over it. and if you havent already, make sure your scanner is ID Searching and not ID scanning, i've seen typos in the database, example TGID 1243 Sheriff Ch.2 when it was TGID 1234. In ID search mode you'll discover new TGID's that aren't yet in the database. Lastly, you can check broadcastify calls to see if there are TGID's in your area, and with a subscription you can go and listen in on recorded audio on other TGIDs, and even track UID's to see if a sheriff switches channels, and what TGID they are going to. Just throwing some stuff out there, i'm relearning all of this myself, best of luck!

The database is wrong if they are encrypted. I spent a few hours yesterday after deleting all of my favorites setting all the encrypted stuff to "Set Avoid". After that I created new favorites and pushed everything to the radios. I have a 100 and 200.

Seems I am ID scanning. How do I change this?

 

[shansmi]

Found where to change that. Wow that brought in all kinda of crap that I am not interested in. Sounded like school buss and utility / public works folks. Changed it back.

 

[W5ATX]

You have to lock out or avoid all the stuff you don't wan to listen to, like busses, etc. then, when an "unknown" TGID appears it will pop up, it might be a new sheriff channel or something of interest. even if it's a concrete company, if you can identify it, submit it to RR and they will add it to the database.

 

[shansmi]

You have to lock out or avoid all the stuff you don't wan to listen to, like busses, etc. then, when an "unknown" TGID appears it will pop up, it might be a new sheriff channel or something of interest. even if it's a concrete company, if you can identify it, submit it to RR and they will add it to the database.

I will play with that. After thinking about it you may be right. Each municipality does have an encrypted service. They may be using those instead of the open channels. I am suspicious since all of them are doing it. All but one city is like that - both of their channels (dispatch and talk) are open i.e. not encrypted.

 

[W5ATX]

if you have your display lit all the time, sometimes you'll see it stop on a TGID and keep going, if you look carefully in the upper right you'll see "ENCRY" if that's the case then it's encrypted. i wouldn't lock it out because sometimes radios in the clear can still talk on that tgid.

 

[shansmi]

You have to lock out or avoid all the stuff you don't wan to listen to, like buses, etc. then, when an "unknown" TGID appears it will pop up, it might be a new sheriff channel or something of interest. even if it's a concrete company, if you can identify it, submit it to RR and they will add it to the database.

So I played with this tonight after all of the other folks had called it a day. What I did is clear all of the "avoid" entries for the department of interest. I then pushed the fav's list to the SDS100. After that I locked in on the department and modified the fav to do an id search vs an id scan. There were 3 channels that did not come up with info. Turns out one was a city that I had in a separate favorites list and the other was a university pd... I verified this on rr.com and my sds200. I then locked onto the department. Next I locked onto the department and site of interest. Nothing unknown has come up and nothing that is supposedly encrypted has hit either.

I have been watching this for an hour or so with the same result. Now I know one community of interest has had hits because a SD Dispatch call came in having a deputy meet the "reporting party" at that PD but nothing picked up from the PD. Remember this PD does com's through the SD over a Law Tac channel...

Texas >> Collin County >> PAWMCo P25 >> Collin County Sheriff is what I am looking at.

 

[W5ATX]

what agency are you trying to listen to exactly? we have some cities dispatched off a sheriff primary channel, and their "talk channels" are on a different part of the system.

 

[shansmi]

what agency are you trying to listen to exactly? we have some cities dispatched off a sheriff primary channel, and their "talk channels" are on a different part of the system.

If you go here in Sentinel:

USA>> Texas >> Collin County >> PAWMCo P25 >> Collin County Sheriff

You will see several PDs with law tac groups. They never get used. The main SD is all over Dispatch1, Inquiry and Ops1. I just never see/hear anything for the cities under the SD on their resective law tac groups. All other cities that I scan use a variety of the channels but they are all independent i.e. not dispatched by the SD. I guess I could be hearing dispatch traffic to them as well as their response but I would have to know officer numbers to prove that.

 

[Ubbe]

My guess is the receivers are capable of much more than -40dBm but just checking. I see nothing in the tech specs for this...

What I can see it only indicates up to -40dBm. There's an automatic gain control in action that reduces the gain the more signal you input. The receiver chip manufacturer Rafael Micro calls it Smart Power Detector, so it will probably start to reduce the signal above that level so can't show higher signal strengths than that.

/Ubbe

 

[shansmi]

What I can see it only indicates up to -40dBm. There's an automatic gain control in action that reduces the gain the more signal you input. The receiver chip manufacturer Rafael Micro calls it Smart Power Detector, so it will probably start to reduce the signal above that level so can't show higher signal strengths than that.

/Ubbe

Thanks! The strongest I have seen is ~ -48dBm to -50dBm for just a flash before going back into the mid 50s. I should be good.