SDS100/200 won't reliably follow p25 p2 systems

[djmorgan]

We have two of these systems in my community (San Antonio). I am well within the coverage area of both (both are using sites from previous EDACS or P24P1 implementations). I have tried downloading the sites without modification from RR (into Sentinel) and I have manually entered one site from one system into my radios (SDS100 and SDS200). I have also analyzed these two P25P2 systems using Unitrunker and with SDR#/DSD+. It is clear, just from listening to these systems with either radio, that they do not reliably follow conversations. When I hear a message I do hear the whole transmission but I don't always hear the response. Or I only hear the reply and not the original transmission. This occurs even with only monitoring one site. Unitrunker and SDS# confirm that there were transmissions it should have heard. Is any one else having a similar problem? I can see no problem with any of the decoding on SDR# and signal strength is strong. This is really frustrating with such expensive radios. If I can't get these working in a few months I will have a completely useless setup as virtually all our public safety and general government are converting. I'm down to listening to a one site DMR the zoo uses. Does anyone else have the same issues? Am I missing something stupid? Thanks for any thoughts or help.

 

[darkness975]

What kind of antenna are you using?

 

[djmorgan]

The SDS200 uses an attic mounted omni 800 mhz gain antenna with ground plane. The SDS100 uses the included antenna (although at this distance from the sites there is minimal loss of performance). The Unitrunker and SDR# use a magnetic mount omni 800mhz gain antenna inside the house o with a "pie tin" for a base.

The sites in question transmitting on 800 and 700. I have near line of site to one of the transmitters...about three miles. Signal strength is high.

Note that the existing EDACS Provoice and P25p1 sites also operate fine with these same antennas (well, perfectly for an EDACS system that is falling apart).

 

[donc13]

What it sounds like to me is it's scanning more than just 1 system and 1 site. And perhaps too short of a delay after the end of transmission.

I could be wrong too.

 

[MStep]

We have two of these systems in my community (San Antonio). I am well within the coverage area of both (both are using sites from previous EDACS or P24P1 implementations). I have tried downloading the sites without modification from RR (into Sentinel) and I have manually entered one site from one system into my radios (SDS100 and SDS200). I have also analyzed these two P25P2 systems using Unitrunker and with SDR#/DSD+. It is clear, just from listening to these systems with either radio, that they do not reliably follow conversations. When I hear a message I do hear the whole transmission but I don't always hear the response. Or I only hear the reply and not the original transmission. This occurs even with only monitoring one site. Unitrunker and SDS# confirm that there were transmissions it should have heard. Is any one else having a similar problem? I can see no problem with any of the decoding on SDR# and signal strength is strong. This is really frustrating with such expensive radios. If I can't get these working in a few months I will have a completely useless setup as virtually all our public safety and general government are converting. I'm down to listening to a one site DMR the zoo uses. Does anyone else have the same issues? Am I missing something stupid? Thanks for any thoughts or help.

No, I don't think you are missing anything. Even at $700 USD, these are just "hobbyist" devices that will not provide 100% dependable operation on all trunked systems that they are designed to follow. I have found that here in the New York City area, many times it can be "hot or miss", even when I am locked onto just one system, as you had mentioned. When you throw "scanning" into the mix, and the complexity of communications systems, the "digital" factor, and a host of other variables, it's actually amazing that these radios can work as well as they do.

Perhaps someone in your area can offer more tips or suggestions on maximizing the settings on your SDS radios for specific systems.

 

[gtaman]

If have the same issue with mine following the AEP Phase 2 system. It’s nearly identical to simulcast distortion on the non SDS scanners. I can track the system fine with my KNG2 radio. The scanners bounces around looking for the voice channel then it drops the control channel. Im not sure if the system is using a Phase 2 control channel. I also have this same issue on a CON+ system near me. It behaves pretty close.

 

[900mhz]

Filter settings and proximity to cell sites are something to consider.

 

[blackbelter]

I have similar experiences with my SDS 200 while my Unication G5 never misses a key up ever . I do realize the limitation of these pagers however my monitoring experiences has been more complete .

 

[900mhz]

I have similar experiences with my SDS 200 while my Unication G5 never misses a key up ever . I do realize the limitation of these pagers however my monitoring experiences has been more complete .

agreed. The Unication deals with everything so much better. No filter settings to tinker with, selectivity around cell sites makes it a no brainer if you are serious about monitoring. Plus the dealer support is second to none.

 

[werinshades]

Try Attenuator and Wide Invert filter settings on specific sites.

 

[ChrisABQ]

Or the SDS radios are just "damn" slow. My SDR Trunk gets everything and that's the difference. SDR Trunk picks up every transmission as it comes in, a scanner, well it's just a scanner and has to go through the entire process of "scanning". Here in Albuquerque, to make things worse, there is a 5 second carrier time-out (all scanner delay settings set to zero), it feels like I'm not getting anything on the radio. The SDR Trunk transmissions never stop. Two completely different animals and the SDR blows away the Uniden scanners.

 

[gtaman]

Or the SDS radios are just "damn" slow. My SDR Trunk gets everything and that's the difference. SDR Trunk picks up every transmission as it comes in, a scanner, well it's just a scanner and has to go through the entire process of "scanning". Here in Albuquerque, to make things worse, there is a 5 second carrier time-out (all scanner delay settings set to zero), it feels like I'm not getting anything on the radio. The SDR Trunk transmissions never stop. Two completely different animals and the SDR blows away the Uniden scanners.

That’s the big thing that bothers me with the Uniden is the damn hang time. My KNG goes back to the control channel the second someone unkeys.

 

[ChrisABQ]

Would love to have a BK (wallet is not built for that), so utilizing streaming to the phone using SDR Trunk. No carrier delay, no simulcast distortion, great audio wherever I go.

 

[gtaman]

Would love to have a BK (wallet is not built for that), so utilizing streaming to the phone using SDR Trunk. No carrier delay, no simulcast distortion, great audio wherever I go.

You can always finance one for 24 months.

 

[donc13]

That’s the big thing that bothers me with the Uniden is the damn hang time. My KNG goes back to the control channel the second someone unkeys.

We'll... Err... Humm.... So why did you buy a $700 Uniden when you had a $2,500 KNG?

Seriously.... You bought a hobby class "scanner" and expect it to be as good as a professional fixed service radio that's also a transmitter?

That's like you saying, wow.. Your Corvette runs so much better and quicker than your Chevy Spark.

Or maybe I missed the sarcasm.

 

[IAmSixNine]

Having a similar situation (G4, KNG2-P800 and SDS100) it took me some time but ultimately the fix (for me) was better antenna and learning to use filters. Several systems i monitor 700mhz P25 P1 and P2 and 1 UHF Connect Plus system all needed me to test out different filters before i was finally happy with the performance of the scanner. Leaving it strictly stock (stock antenna and no filters) the device is not great. Currently have the old school radio shack 800 antenna on mine and even going with that i notice a big difference in signal quality. Remember this is a digital signal so any interference represents packet loss and the more of that the worse the decoding is.

 

[gtaman]

We'll... Err... Humm.... So why did you buy a $700 Uniden when you had a $2,500 KNG?

Seriously.... You bought a hobby class "scanner" and expect it to be as good as a professional fixed service radio that's also a transmitter?

That's like you saying, wow.. Your Corvette runs so much better and quicker than your Chevy Spark.

Or maybe I missed the sarcasm.

Well my order went KNG-800 (Pre SDS was even a thing) SDS-200 that I got for 400bucks then I upgraded to a KNG2-800. The SDS does a fantastic job with pretty much everything. But there seems the be an issue with systems that use a TDMA control channel. I’m just stating that I also have the issue. My KNG will always be my go to.

 

[sallen07]

systems that use a TDMA control channel.

Ding-ding-ding we have a winner.

Uniden scanners do not currently track TDMA control channels. According to the Uniden rep, "it's on the high-priority list".

 

[KevinC]

Well my order went KNG-800 (Pre SDS was even a thing) SDS-200 that I got for 400bucks then I upgraded to a KNG2-800. The SDS does a fantastic job with pretty much everything. But there seems the be an issue with systems that use a TDMA control channel. I’m just stating that I also have the issue. My KNG will always be my go to.

Does your KNG2-800 work on a TDMA CC?

 

[gmclam]

When I first started using an SDS scanner, it quickly became apparent that you don't want to scan more than one trunked system (or include scanning of any conventional frequencies) if your goal is not missing stuff. As soon as it's not monitoring the control channel, you risk missing something.