Questions and Concerns on P25 and Simulcast - New SDS-200 Owner

[wolverine871]

Just a heads up, I am very new to scanners and radios so if I make any mistakes I'd like you to please inform me.

Background:​

I recently bought an SDS200 because I've heard really good things about them. I live in the Charlotte, NC area and have looked at the Charlotte UASI page quite a bit. I see that they are using P25p1 and that Mecklenburg County is on a simulcast system. Considering the county utilizes simulcast I figured the SDS200 would work really well in this area.

I am using the SDS200 inside of my house and have tried using the stock antenna it ships with and have also tried this antenna from Amazon.

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Questions and Concerns:​

I have imported the Charlotte UASI system from Sentinel to a favorites list which includes multiple sites: Mecklenburg Simulcast, Union Simulcast, Cabarrus Simulcast, [TEMP] - Steele Creek, Mooresville, Gastonia Simulcast, and Stanly Simulcast. From what I understand, all of these sites make up multiple towers that repeat the digital signals over a broader area. I have it in my mind that the towers are "meshed together" and therefore if somebody transmits on the south side of the city you'd still be able to hear them just as well from the north side if you're relatively near one of the simulcast towers.

Like I mentioned, I currently have the entire Charlotte UASI with all of the sites imported onto the SDS200. Let's say that I want to only listen to Charlotte-Mecklenburg Police department, I could go onto the SDS200 itself and hold on that department which in turn only will scan through the channels inside of the Charlotte-Mecklenburg Police department. I realize that there are certain channels inside this department that are encrypted, although what I'm really confused about is the ability to not hear that many of the non-encrypted P25 channels. There are several conference and dispatch channels that are inside of this department yet I can only pick up around 2 or 3.

Since I'm in the Charlotte area, I figured that I can pick up a ton of what is being broadcast inside the UASI system, but so far I really am disappointed with how little I can hear. I have the attenuator turned off, filter set to global which means it's on normal, and have set the P25 NAC to 2D0. All of these options were set inside of the Mecklenburg Simulcast site on the radio itself. My RSSI is fluctuates between -80 and -105, depending on what site it's scanning through. I've found that if I do the "Site Hold" on specifically the Mecklenburg Simulcast, I will receive an RSSI more towards -80 rather than higher negative values. The noise level seems to fluctuate like crazy... all the way from in the hundreds then it jumps to tens of thousands. At the top of the display I usually see DATA and LINK being shown, when somebody talks it switches to P25 until they stop.

Lastly, another concern/question that I have is about the audio quality of what I'm receiving. If I happen to pick up people talking on the Charlotte-Mecklenburg Police department it sounds incredibly mumbled and robotic to the point where you can only comprehend about 20-30% of what they are saying... Is there absolutely any way to make the voices sound intelligible? That is one of the most frustrating parts of this. Another struggle is voices that get cut off mid sentence. They will be talking and then just out of nowhere it stops completely. The only department that sounds even remotely decent is the Charlotte Area Transit System, which I don't care too much to monitor. That's really the only other department inside of the system that I've been able to hear. I would really like to be able to monitor police, fire, and EMS in the Charlotte area and also be able to understand what they're saying.

Any help would be greatly appreciated, I'm really trying to get this to work!

 

[Randyk4661]

As someone that has been playing with the filters here in So. Calif., I have found that trying all the filters including off varies from system to system. LAPD I use wide invert. Another system I turned the filter off now it's around -40 RSSI, It's now is much clearer to listen to.
There is alot of trial an error using these radios
Make sure that you have as few sites in scan as possible, one or two is best for a single favorites list. The more sites you scan, it will slow down what you hear.
If you have four areas to cover, make a separate favorites list with each site for each area. One favorites list with four sites and all the talkgroups for all the areas will slow the scanner to a crawl.
Also Apply the best filter setting for each site, don't use a global setting as this could also slow down the scanner, don't use "auto" settings.

Good luck, once you dial in the setting you should be good for listening.

 

[Harold]

Delete all but 1 site. Set squelch to 2 or even 0.

 

[WX4JCW]

also forget the RSSI, adjust the filters and get a good antenna like the remtronix, make sure D-Error is active in your display the D-Error is the key and the closer to 0 the Better, if you can achieve 0 all the time thats best

 

[wolverine871]

As someone that has been playing with the filters here in So. Calif., I have found that trying all the filters including off varies from system to system. LAPD I use wide invert. Another system I turned the filter off now it's around -40 RSSI, It's now is much clearer to listen to.
There is alot of trial an error using these radios
Make sure that you have as few sites in scan as possible, one or two is best for a single favorites list. The more sites you scan, it will slow down what you hear.
If you have four areas to cover, make a separate favorites list with each site for each area. One favorites list with four sites and all the talkgroups for all the areas will slow the scanner to a crawl.
Also Apply the best filter setting for each site, don't use a global setting as this could also slow down the scanner, don't use "auto" settings.

Good luck, once you dial in the setting you should be good for listening.

Thank you for your help. I'll have to mess with the filters more per site.

Delete all but 1 site. Set squelch to 2 or even 0.

Yep, squelch is set to 0.

also forget the RSSI, adjust the filters and get a good antenna like the remtronix, make sure D-Error is active in your display the D-Error is the key and the closer to 0 the Better, if you can achieve 0 all the time thats best

I will have to check the D-Error value. I think I'll need to edit the display to be able to see that. I'm not seeing it by default on the detailed display option.

I'm think I may get the BNC 800 MHz REMTRONIX REM-830B Base Antenna (back of set). Do you think this is the best option for indoor antennas? I know it's 700-900MHz only. Are there any other better options for SDS200?

 

[Ubbe]

The noise level seems to fluctuate like crazy...

This is normal for receiving a digital system. Noise level are only making sense with analog systems, and when there's no one talking, just a silent carrier.

Police department it sounds incredibly mumbled and robotic

They will be talking and then just out of nowhere it stops completely.

It's a high level of errors in the digital data you receive that makes it robotic and if it gets to severe it will stop completely to decode the data.
It's a tedious task of trying all filter settings, including Off, and also try them with IFX both On and Off, to try and find one combination that works. All those setting are both frequency and location dependent and it could be that one frequency in a site needs one setting and another frequency in the same site needs a different setting, and that's not possible to do.

/Ubbe

 

[n1chu]

First, I suggest you ask a Radio Reference (RR) Admin to move your post to the Regional Forums… they are listed by state. RR frowns on duplicate posts so, that’s where the admin comes in. And once on the statewide forum you should be able to talk with someone in your area familiar with the systems you are interested in… maybe even meet up with them over coffee and your scanners. You will at very least determine if your reception of only a couple of TG’s is normal or not. And if you do meet up, and after hearing a “known good” SDS200 programmed scanner in action, bring your laptop, to copy the SD card they are using to your SD card… then plug it in to your scanner and see how it plays… they should be identical! (You can edit it later to fit your desires.)

The aftermarket antenna should play marginally better than the stock antenna, I doubt it has any gain. That being said, you’ve now got a mobile antenna to use should you ever go mobile.

As for the agencies that you receive as garbled, you might try the various filter settings. Experiment with them. And know that your results may differ from others, even as close as next door, or the next room. The filters are very “location” dependent. I started out setting all filters off, including global filter settings. I then tried each filter on a system. My results didn’t show any noticeable differences so I run the SDS200 with all filters off, including the global settings. I live in Ct. and listen to the Ct. St. Police who hang out on Connecticut Land Mobile Radio Network (CLMRN), a simulcast system. But so far I am one of those fortunate people who don’t experience simulcast issues. That may change as two abutting towns to mine are moving onto CLMRN, the additional sites that will be built will be closer to me and I suspect may cause simulcast to raise its ugly head. Then it’s back to the drawing board for me.

Uniden recently pushed out a firmware update. You should update your scanner and Sentinel programming, which will be needed to download the new firmware. (When I went after the download I was prompted to first update Sentinel, then attempt the firmware download.)

 

[dave3825]

I recently bought an SDS200

Just curious, did you update the firmware on the scanner and the full database in Sentinel?

 

[n1chu]

No. The Sentinel software is the program you use to update the firmware in your SDS200. In Sentinel find the firmware update and click on it… it should prompt you to first update the Sentinel software. Once that is done start Sentinel again and go for the firmware update.

 

[wolverine871]

This is normal for receiving a digital system. Noise level are only making sense with analog systems, and when there's no one talking, just a silent carrier.

It's a high level of errors in the digital data you receive that makes it robotic and if it gets to severe it will stop completely to decode the data.
It's a tedious task of trying all filter settings, including Off, and also try them with IFX both On and Off, to try and find one combination that works. All those setting are both frequency and location dependent and it could be that one frequency in a site needs one setting and another frequency in the same site needs a different setting, and that's not possible to do.

/Ubbe

I haven't messed with IFX at all yet. I can find any helpful information on this in the SDS200 manual. And yeah it seems to be very location dependent. I just want to ensure that I have a proper hardware config to enable the smooth usage of simulcast. I'm really new to radios and antennas, pretty much everything RF in general. I'm trying to get an idea of what I need to make this work more efficiently for my situation.

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1) First, I suggest you ask a Radio Reference (RR) Admin to move your post to the Regional Forums… they are listed by state. RR frowns on duplicate posts so, that’s where the admin comes in.

2) The aftermarket antenna should play marginally better than the stock antenna, I doubt it has any gain. That being said, you’ve now got a mobile antenna to use should you ever go mobile.

3) As for the agencies that you receive as garbled, you might try the various filter settings. Experiment with them. And know that your results may differ from others, even as close as next door, or the next room. The filters are very “location” dependent. I started out setting all filters off, including global filter settings. I then tried each filter on a system. My results didn’t show any noticeable differences so I run the SDS200 with all filters off, including the global settings. I live in Ct. and listen to the Ct. St. Police who hang out on Connecticut Land Mobile Radio Network (CLMRN), a simulcast system. But so far I am one of those fortunate people who don’t experience simulcast issues. That may change as two abutting towns to mine are moving onto CLMRN, the additional sites that will be built will be closer to me and I suspect may cause simulcast to raise its ugly head. Then it’s back to the drawing board for me.

4) Uniden recently pushed out a firmware update. You should update your scanner and Sentinel programming, which will be needed to download the new firmware. (When I went after the download I was prompted to first update Sentinel, then attempt the firmware download.)

1) How should I ask an admin to move this to the regional forums section? I'm assuming they can see this post anyways, not sure what I have to do to get them to move it to a regional section. That sounds like a pretty good idea.

2) I actually just tried the antenna I mentioned and put it on the roof of my car with the magnet. It seemed to work pretty well on there. It's not tuned to 800-900MHz as far as I know, Amazon says it's 20-1300MHz. Any suggestions on specifically tuned antennas for 800-900MHz, one that I could use indoors and then a separate one for on my car? I prefer not to have to drill any holes or permanently mount something to the car (for now at least), FYI. I'd ideally also want an antenna for indoors too. I don't mind carrying the SDS200 back and forth from inside to mobile, as I'm not actually mounting it in the car.

3) I've been messing around quite a bit with the different filter options and it's really tough to tell what is actually making a difference and what is not. I'm sure if I use it indoors I'll have to have specific settings changed to suit that area v.s. if I have the scanner in my car going mobile. I could just create two different favorite lists and have separate options for each.

4) Yes, I have updated my firmware to 1.23.03 (12/28/23). There was also a CPU update after the firmware installed itself. I used Sentinel to upgrade the firmware and it seemed successful.

 

[AK9R]

How should I ask an admin to move this to the regional forums section?

See the link at the bottom of each message that says "Report". Clicking that button is how you alert a moderator if there is a problem with a post or thread.

Your thread has been moved to the North Carolina Discussion Forum.

 

[phask]

have imported the Charlotte UASI system from Sentinel to a favorites list which includes multiple sites: Mecklenburg Simulcast, Union Simulcast, Cabarrus Simulcast, [TEMP] - Steele Creek, Mooresville, Gastonia Simulcast, and Stanly Simulcast. From what I understand, all of these sites make up multiple towers that repeat the digital signals over a broader area. I have it in my mind that the towers are "meshed together" and therefore if somebody transmits on the south side of the city you'd still be able to hear them just as well from the north side if you're relatively near one of the simulcast towers.

Not quite. All of those simulcast sites are themselves composed of multiple sites or towers. For example - Gastonia by itself could act independently, are they could all be combined and act together. Only someone local can answer that question.

I'd assign quick keys to each one, that way you can turn them on and off to see what works. You can also use the analyze feature to help.

 

[hamstang]

If you want just Charlotte, only program Mecklenburg site with it's 30 frequencies. IMPORTANT: make sure you have nearly all Service Types enabled and you should hear almost constant traffic.

 

[wolverine871]

If you want just Charlotte, only program Mecklenburg site with it's 30 frequencies. IMPORTANT: make sure you have nearly all Service Types enabled and you should hear almost constant traffic.

I am testing this right now. I have the Mecklenburg site as my only one now, none of the others listed under the Charlotte UASI. I also have pretty much all service types enabled.

What departments/talkgroups are you monitoring inside of the Charlotte UASI? I'm mainly only hearing CMPD and Charlotte Area Transit System. Those are really the only ones that are being hit out of all the departments in the system.

 

[hamstang]

I am testing this right now. I have the Mecklenburg site as my only one now, none of the others listed under the Charlotte UASI. I also have pretty much all service types enabled.

What departments/talkgroups are you monitoring inside of the Charlotte UASI? I'm mainly only hearing CMPD and Charlotte Area Transit System. Those are really the only ones that are being hit out of all the departments in the system.

I monitor CFD,CMPD NORTH,MECK COUNTY FIRE/EMS,MECK CO. MUTUAL AID, SYSTEMWIDE MUTUAL AID. CFD is quite active since they respond to all medical calls. You should be hearing near constant calls except early morning.

 

[brian]

Regarding CMPD channels, keep in mind that it's typical for dispatch channels to be patched together. The dispatch center doesn't have enough dispatchers to assign to each division's dispatch channel, so one dispatcher will typically handle 2 or more at a time. In order to eliminate having two channels talking at the same time, the dispatcher patches channels together so they act like a single channel. From your perspective, it's going to show up in the display as one specific channel talking all the time. I'm not particularly familiar with how the SDS scanners display and handle patches, but this may explain why it seems you're only receiving a few channels for CMPD. There used to be a list of dispatch channels that were typically patched together though I haven't seen that in a long time. This page might help you determine which divisions you're hearing on a particular channel: Mecklenburg County (NC) - The RadioReference Wiki.

As others mentioned, regarding sites, if you're in Charlotte, you want to monitor the Mecklenburg County Simulcast site only. Each site somewhat operates as an independent system. With some exceptions, you're not going to hear much from Gaston or Cabarrus County on the Mecklenburg Co site. Likewise, you're not going to hear a lot of Mecklenburg Co channels on the Gaston or Cabarrus County sites. That's the nature of the way this system is set up.

Reliable reception of P25 simulcast sites has a lot of variables, and the additional variable of filters on the SDS scanners makes it trickier. Antenna and location have a lot of do with it also. Sometimes, a better antenna helps, other times it may make things worse. Sometimes moving the scanner a few inches one way or another may make a difference. As others mentioned, trial and error (and the patience that goes along with it) is required to figure out the best configuration in your specific location. Be confident that you have the best consumer scanner available to receive the UASI system. You should be able to get it optimized to work quite well.

Regarding encryption, you should hear everything that's not encrypted. Keep in mind that the RadioReference database may not be 100% accurate/up to date on talkgroups and on what's encrypted or not. Some things not marked encrypted might be, and vice versa. The SDS series will ignore encrypted communications by default, so you won't know what you're not hearing, if that makes any sense. Usually that's a good thing, but as you're getting started and trying to figure things out, it can be more challenging.

Stick with it. Good luck.

 

[hamstang]

If you have Charlotte UASI correctly programmed and set System Option to ID SEARCH, not ID SCAN, you should hear every user of UASI that you have Service Type enabled. Today is a holiday for many city employees, so system not as busy as a normal weekday. On another note, your scanner may stop briefly on active encrypted talk groups and you will briefly see ENCRY instead of P25, Link, or Data at top of display under date.

 

[wolverine871]

Regarding CMPD channels, keep in mind that it's typical for dispatch channels to be patched together. The dispatch center doesn't have enough dispatchers to assign to each division's dispatch channel, so one dispatcher will typically handle 2 or more at a time. In order to eliminate having two channels talking at the same time, the dispatcher patches channels together so they act like a single channel. From your perspective, it's going to show up in the display as one specific channel talking all the time. I'm not particularly familiar with how the SDS scanners display and handle patches, but this may explain why it seems you're only receiving a few channels for CMPD. There used to be a list of dispatch channels that were typically patched together though I haven't seen that in a long time. This page might help you determine which divisions you're hearing on a particular channel: Mecklenburg County (NC) - The RadioReference Wiki.

As others mentioned, regarding sites, if you're in Charlotte, you want to monitor the Mecklenburg County Simulcast site only. Each site somewhat operates as an independent system. With some exceptions, you're not going to hear much from Gaston or Cabarrus County on the Mecklenburg Co site. Likewise, you're not going to hear a lot of Mecklenburg Co channels on the Gaston or Cabarrus County sites. That's the nature of the way this system is set up.

Reliable reception of P25 simulcast sites has a lot of variables, and the additional variable of filters on the SDS scanners makes it trickier. Antenna and location have a lot of do with it also. Sometimes, a better antenna helps, other times it may make things worse. Sometimes moving the scanner a few inches one way or another may make a difference. As others mentioned, trial and error (and the patience that goes along with it) is required to figure out the best configuration in your specific location. Be confident that you have the best consumer scanner available to receive the UASI system. You should be able to get it optimized to work quite well.

Regarding encryption, you should hear everything that's not encrypted. Keep in mind that the RadioReference database may not be 100% accurate/up to date on talkgroups and on what's encrypted or not. Some things not marked encrypted might be, and vice versa. The SDS series will ignore encrypted communications by default, so you won't know what you're not hearing, if that makes any sense. Usually that's a good thing, but as you're getting started and trying to figure things out, it can be more challenging.

Stick with it. Good luck.

Thank you for your helpful insight here. I now only have the Mecklenburg County Simulcast site only, none of the others.

I'm hearing pretty regular voice traffic now and have moved my antenna a bit and seem to have a better RSSI reading. I'm now regularly in the -70 to -85 range. Is this good enough?

I'm still having the same issue with the very hard to understand voices. I feel like the majority of the transmissions I'm hearing are extremely hard to understand, even impossible at times. I really don't get why this is happening or how I could fix this. The times that I do hear people more clearly they are usually talking slower and more emphasized. I'm also running into a problem where sometimes a person will transmit, but they are twice or more quiet sounding than the dispatcher that they are talking to. Is this normal? I usually have my volume set to 15 and squelch set to 0.

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If you have Charlotte UASI correctly programmed and set System Option to ID SEARCH, not ID SCAN, you should hear every user of UASI that you have Service Type enabled. Today is a holiday for many city employees, so system not as busy as a normal weekday. On another note, your scanner may stop briefly on active encrypted talk groups and you will briefly see ENCRY instead of P25, Link, or Data at top of display under date.

Got it. I have set ID SEARCH on the system level now. I didn't have that option turned on before you mentioned this. Hopefully this can improve my issues. If you read above, I'm still running into some pretty annoying problems with being able to hear people clearly.

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Is there an antenna that you suggest buying for the SDS200 specifically? The one that I have right now seems to be better than the stock one that the scanner comes with, but I'm sure it's still not even close to the best option. I've heard good things about the REM-830B, but am unsure of how my overall receiving range will be affected. It just looks so tiny.

 

[hamstang]

I use the antenna that came with the SDS200. UASI is in the 800mhz frequency range so a short antenna is all that's needed. I'm clueless about your bad audio. Did you acquire that radio new from a dealer, or used? Your RSSI is the same as mine.

 

[wolverine871]

I use the antenna that came with the SDS200. UASI is in the 800mhz frequency range so a short antenna is all that's needed. I'm clueless about your bad audio. Did you acquire that radio new from a dealer, or used? Your RSSI is the same as mine.

The SDS200 unit I bought was off of Amazon and was listed as new. It was the full $699.99 price.

Yeah, the bad audio is really annoying. What filter do you have selected for your Mecklenburg County Simulcast site?

Something else that I am wondering if we can try is if you can upload your SDS200 config as a file to here and then I can import it and try it on mine. Yours seems to be working fully without problems. It's worth a shot.