APX6000/SRX2200 Isolated TX Issue

[ExpatLMRGuy]

Hello guys and gals, this is my first post here so forgive me if I'm breaking any rules!

I've been having an issue transmitting on a particular TDMA/FDMA DDM enabled Talkgroup.

- CH 1 and CH 2 are under a single personality as two different talkgroups. We'll refer to CH 1 as "LMR" and CH 2 as "COMM".

I've gone over every menu item of the codeplug and have yet to determine why I have no problem transmitting on COMM but when I switch to LMR, I get no audio being pushed out. The funny thing is, I can RX on LMR perfectly.

Things to consider:

- The Personality is not RX only.
- Only COMM accepts the transmit
- I can see the radio affiliated on the network via Zone Watch
- Zone Watch drops the call 3 seconds after.
- I have no problem pushing an AES key over OTAR to the KMF
- The TX indicator light displays, and stays activated throughout the PTT

What makes even less sense to me is that the two other SRX-2200's that I have, work perfectly fine with the same exact codeplug.

The only differences I spotted were the Flashcodes. The two radios that work, both have the same Flashcodes and the radio that doesn't work - has a different Flashcode. But then again, why would the COMM channel work if it were a flashcode related error?

I know there is a lot going on in this thread and hopefully I didn't confuse you! If you need more details, I'll share as much as I can!

 

[KevinC]

Dropping the channel after 3 seconds is a good indication the bandplan is incorrect. The channel is waiting for the radio, but it never arrives since the bandplan is wrong, so it drops the call after about 2 seconds.

I bet some radios are flashed for TDMA and some aren't. Can you make the TG FDMA only and test again?

 

[KevinC]

Thinking about more. When the 2 radios that talk to each other keyup does ZoneWatch show the call as TDMA or FDMA? And does that change when the oddball radio keys up?

 

[ExpatLMRGuy]

Thank you for the response Kevin! I verified the Bandplan and everything seems to be correct. When I key up, Zonewatch does recognize my radio as TDMA. This problem seems to only affect certain channels (9/16) to be specific.

 

[ExpatLMRGuy]

I just realized I mistakenly fat-fingered the title of this post. Can you please change it to:

* APX6000/SRX2200

 

[KevinC]

Have you verified those channels are programmed the same as other channels in the site controller? Such as using the correct band plan element?

And are these channels set properly in UNCW?

The reason the channel drops after 2-3 seconds is because it's been told to expect an inbound signal, but never receives one. We just need to figure out why. This can be caused by the following...

Incorrect bandplan
Incorrect NAC
Mismatch in programming in the site controller vs the individual station.

 

[ExpatLMRGuy]

Kevin,

I ended up reverting my Talkgroups back to FDMA-only in the User Configuration Manager and that seemed to fix the problem and get rid of the busy tones and dropped calls... well, sort of... Because now my radios are programmed for TDMA DDM in the "Trunking System" bandplan (In CPS R16.0) but the feature isn't being utilized due to the fact that I had to revert back to FDMA in my User Configuration Manager.

I will have to try and figure out why only some of the channels worked in Dual Dynamic Mode and others didn't... Maybe it is as you said, something in the bandplan just isn't right.

Well, that's a project for later this evening!

 

[KevinC]

Since everything seems to work in FDMA, I'd look at the bandplan of the radios that make TDMA stop working.

 

[ExpatLMRGuy]

Since everything seems to work in FDMA, I'd look at the bandplan of the radios that make TDMA stop working.

Thank you Kevin, that's exactly what we did. Apparently some radios on the network had the incorrect bandplan programmed while others had the correct one. We've developed a solution and are implementing it

Thank you all for your feedback and help, I don't come on here often as my work days are pretty long, but I do appreciate those who regularly frequent this site and provide people like myself with the help we need!