Receiving DMR Signal But No Audio
Receiving DMR Signal But No Audio
Hello all, I'd like to thank everyone involved with the development of this firmware first of all but I am running into a problem. When connected to any of my hotpsots at my QTH sometimes I will be receiving a signal but not hearing the audio. I can change channels and go back to the channel that I was not hearing and audio will be passing through. It doesn't matter which station is transmitting and it is very random. I am using a TYT MD-UV390 with Firmware version 20250207. Any help is greatly appreciated.
Re: Receiving DMR Signal But No Audio
Is your hotspot duplex or simplex?
Is your CPU is STM32 or TYT? (check this in Menu -> Firmware info)
I have experienced the same in the past on my TYT CPU radio with duplex hotspot. The problem goes away after I have decided to stop using duplex hotspot.
Is your CPU is STM32 or TYT? (check this in Menu -> Firmware info)
I have experienced the same in the past on my TYT CPU radio with duplex hotspot. The problem goes away after I have decided to stop using duplex hotspot.
Re: Receiving DMR Signal But No Audio
Duplex hotspots and DMR seems to be tricky, I have one that works fine with D-Star but running a TDMA protocol with two timeslots seems
to be much more sensitive.
And our 70 cm band in the Nordic countries is only 432-438 MHz which makes it difficult to get TX/RX separation , especially if you follow the
bandplan where the repeater shift is 2 MHz.
Re: Receiving DMR Signal But No Audio
Yep, totally agreed, I've tried 10 MHz shift, still have de-sensitization issues. I've a thought of doing notch filter and duplexer to make the hotspot act more like the repeater, but it seems too much. I ended up config it to run as simplex.SA0BUX wrote: ↑Wed Feb 12, 2025 1:56 pm
Duplex hotspots and DMR seems to be tricky, I have one that works fine with D-Star but running a TDMA protocol with two timeslots seems
to be much more sensitive.
And our 70 cm band in the Nordic countries is only 432-438 MHz which makes it difficult to get TX/RX separation , especially if you follow the
bandplan where the repeater shift is 2 MHz.
Re: Receiving DMR Signal But No Audio
SA0BUX wrote: ↑Wed Feb 12, 2025 1:56 pmDuplex hotspots and DMR seems to be tricky, I have one that works fine with D-Star but running a TDMA protocol with two timeslots seems
to be much more sensitive.
And our 70 cm band in the Nordic countries is only 432-438 MHz which makes it difficult to get TX/RX separation , especially if you follow the
bandplan where the repeater shift is 2 MHz.
The more than 5Mhz separation is suggested on Dual HS in order to avoid issues on ADF7021 ICs.
Any other "dual" nodes, don't need to follow that suggestion if good quality resonant splitter used on RX/TX radios.
Obviously 2Mhz shift is hard and expensive to get property working anyway not impossible.
Maybe a special request to admin for those situations will help you getting more than 2Mhz...
Re: Receiving DMR Signal But No Audio
With "admin" you mean the Swedish Telecommunication authorities ?EA3FA wrote: ↑Wed Mar 05, 2025 1:09 amSA0BUX wrote: ↑Wed Feb 12, 2025 1:56 pmDuplex hotspots and DMR seems to be tricky, I have one that works fine with D-Star but running a TDMA protocol with two timeslots seems
to be much more sensitive.
And our 70 cm band in the Nordic countries is only 432-438 MHz which makes it difficult to get TX/RX separation , especially if you follow the
bandplan where the repeater shift is 2 MHz.
The more than 5Mhz separation is suggested on Dual HS in order to avoid issues on ADF7021 ICs.
Any other "dual" nodes, don't need to follow that suggestion if good quality resonant splitter used on RX/TX radios.
Obviously 2Mhz shift is hard and expensive to get property working anyway not impossible.
Maybe a special request to admin for those situations will help you getting more than 2Mhz...
I doubt they would care about such request, they are not so amateur radio friendly.
Anyway it's no big deal , I adjusted the oscillator on the MMDVM Dual HS with my GPSDO referenced frequency counter now so it much better.
BER is down into the "green area" and no "Timeout" on TX anymore.
And I noticed that a TG4000 Unlink have no effect when someone is talking on the TS ( TG91) anyway which would have been a "feature" sometimes
Re: Receiving DMR Signal But No Audio
You cannot unlink while there is activity. You can use "drop call" in your BM account and quickly send 4000 from your radio.
Re: Receiving DMR Signal But No Audio
Re: Receiving DMR Signal But No Audio
Unlink command mist be sent when your system is not receiving not RF nor network.SA0BUX wrote: ↑Wed Mar 05, 2025 6:59 amWith "admin" you mean the Swedish Telecommunication authorities ?EA3FA wrote: ↑Wed Mar 05, 2025 1:09 amSA0BUX wrote: ↑Wed Feb 12, 2025 1:56 pm
Duplex hotspots and DMR seems to be tricky, I have one that works fine with D-Star but running a TDMA protocol with two timeslots seems
to be much more sensitive.
And our 70 cm band in the Nordic countries is only 432-438 MHz which makes it difficult to get TX/RX separation , especially if you follow the
bandplan where the repeater shift is 2 MHz.
The more than 5Mhz separation is suggested on Dual HS in order to avoid issues on ADF7021 ICs.
Any other "dual" nodes, don't need to follow that suggestion if good quality resonant splitter used on RX/TX radios.
Obviously 2Mhz shift is hard and expensive to get property working anyway not impossible.
Maybe a special request to admin for those situations will help you getting more than 2Mhz...
I doubt they would care about such request, they are not so amateur radio friendly.
Anyway it's no big deal , I adjusted the oscillator on the MMDVM Dual HS with my GPSDO referenced frequency counter now so it much better.
BER is down into the "green area" and no "Timeout" on TX anymore.
And I noticed that a TG4000 Unlink have no effect when someone is talking on the TS ( TG91) anyway which would have been a "feature" sometimes
At this point, in Pi-Star or WPSD, for BM is quite useful to have the API KEY installed. This allows you to MUTE the current talker and being free to TG4000 keying.
