DMR MMDVM does not see my radio

Help with DMR issues
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KL6M
Posts: 2
Joined: Fri Jan 17, 2020 8:38 pm

DMR MMDVM does not see my radio

Post by KL6M » Mon Feb 10, 2020 10:37 pm

I have a Pi-zero-w and a MMDVM I got on Ebay for $18.98 from, you guessed it, China. I cannot get the radio portion to work. The MMDVM does not respond to my radio TX. I have Pi-star running and have checked and rechecked all configuration entries and see nothing wrong.

My MMDVM has a STM32F103 and ADF7021. On the Admin page it detects the hat as FW HS_HAT:v1.4.17. I selected modem type STM-DVM/MMDVM_HS-Raspberry Pi Hat (GPIO).

It boots up with all the LEDs flasing and settles with green power on solid and rapid flashing red SVC. If I press reset button on the hat, the red flashes much slower.

I changed TX & RX frequencies on both Pi-star and my radio from 446.5 to 433.2 which made no difference.

I fiddled with a few RXDCOoffsets and RXOffsets in Pi-star expert with no luck. I checked the TCXO frequency with a counter and it measured 14.74556, so only 40Hz low. I also checked frequency on my Retevis RT3 and it is only 20Hz low.

Any other ideas? Pleeeeeze? [email protected]

VK3HAW
Posts: 39
Joined: Sat Dec 14, 2019 3:31 am

Re: DMR MMDVM does not see my radio

Post by VK3HAW » Wed Feb 12, 2020 5:26 am

Had any luck? You could try changing the RX/TX offsets by -150 at a time and see if it starts hearing each time, maybe go as far as -1000.

This post may help viewtopic.php?f=5&t=1983

KL6M
Posts: 2
Joined: Fri Jan 17, 2020 8:38 pm

Re: DMR MMDVM does not see my radio

Post by KL6M » Thu Feb 27, 2020 6:29 pm

I tried varying offsets over a wide range and still not working. So I borrowed another MMDVM known to be working and plugged it in. Everything worked perfect. Then I realized once connected to a TG I could turn off the hotspot and plug in the bad MMDVM and the system would stay connected to that TG. So the bad MMDVM DMR LED and PTT LED were active for any incoming signals. So I looked at the output of the bad MMDVM with a spectrum analyzer and there was NO OUTPUT. So my conclusion is that the ATF7102 is bad, or the STM32 is not communicating the setup info to the 7102. I tried reflashing the MMDVM and that did not help. I believe my board is NO GOOD. I may troubleshoot further when I have time.

sm7rdx
Posts: 8
Joined: Sun Aug 04, 2019 11:38 am

Re: DMR MMDVM does not see my radio

Post by sm7rdx » Fri Mar 13, 2020 2:35 pm

I suppose you have set the right password in Brandmeister dashboard? That was my problem when I started
with DMR. The same password should be set in Pi-star DMR-setup.

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