TX audio issue, RX is OK

Help with DMR issues
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VA2DG
Posts: 8
Joined: Tue Dec 25, 2018 4:17 pm
Location: Montreal South Shore

TX audio issue, RX is OK

Post by VA2DG »

Hi everyone,
i am building a DMR Repeater with 2 CMD1550LS, and a Repeater builder MMDVM V3 board.

So far so good the repeater TX is excellent putting TG91 static and i can receive everything on my MD380.

But when i transmit with my MD380, Repeater is receiving and TX is keyed and i see myself on my RPT Pi-Star dashboard.

I also see myself on other repeater or Hotspot Dashboard when testing on TG302233. But on my XPR4580 (900) on TG302233 i do receive the DMR ID but no audio.

Transmitting with my XPR on 900 Repeater and i do received my audio on my MD380 thru the new Repeater.

On thing i dont have duplexor yet but TX is in a dummy load at Low Power and RX is in dummy load too.

Doing a test on the Parrot i got out and when the parrot answer back i get the carrier but no audio.

Here is my component testing.
With a headset with Sleeve to ground and tip as a test lead.
1. i get unsquelch noise at pin 6 of DB9,
2. then between capacitor C14 and R6 100k pot i have noise audio,
3. between capacitor C14 and R6 100k pot i have noise audio,
4. then between R6 100k pot and R10 i have noise audio,
5. then between R10 10k and C20 still have noise audio,
6. then after C20 Cap still have noise audio.

It is like if the RPT builder board is decoding the RX audio, because it does key the TX but no audio hear on other Local radio or other radio on other Repeater.

Any body have a clue of the problem?

Right now i am blocked because did too many short transmission within 60 sec. so i have to wait 1 hour before i can test again.

thanks
STM32_DVM_V3.jpg
STM32_DVM_V3.jpg (60.51 KiB) Viewed 1148 times
73's
Daniel VA2DG
AF6VN
Posts: 821
Joined: Fri Jul 20, 2018 1:15 am

Re: TX audio issue, RX is OK

Post by AF6VN »

Have you confirmed the MD380 is actually sending audio? Activate "talk around" (simplex mode, if you had that option checked in the code plug) and see if your other unit outputs audio when you speak into the MD380.

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AF6VN
Dennis L Bieber
VA2DG
Posts: 8
Joined: Tue Dec 25, 2018 4:17 pm
Location: Montreal South Shore

Re: TX audio issue, RX is OK

Post by VA2DG »

Well just found the issue
i was using a MD380 VHF that i never used and today i decided to use my Kydera CDr300UV and on my first try on the parrot and got the answer with my voice.
So i took the MD380 and when to 146.52 and surprise no audio on transmit but the DTMF are going thru, Try with a external Mic and working.
So probably the Mic cartridge is dead.
3 Day lost trying with this faulty radio.

Case is closed now.
73's
Daniel VA2DG
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