Audio interruptions with Radioddity GD-77

[IZ0MXY]

Hi Roger,

I recently restored the manufacturer's original firmware on some OM friends' GD-77s, because they noticed that the audio returned by the devices in DMR with the Open GD77 firmware, is affected by interruptions and irregularities, compared to listening with the original firmware
(currently ver. 4.3.3)

The problem manifests itself when listening with hotspots and nodes based on MMDVM hotspots with mobile radios (eg. Motorola eg. GM340 - GM350 -GM950) and with the classic simplex and duplex hotspots but it is also noticeable by listening to native dmr repeaters, but the problem is noticed by less.
The devices (3) were purchased at different times, from various suppliers and the production dates are different.

I repeated the same test also on my old GD-77, installing the manufacturer's firmware and in fact I found an improvement in listening both with simplex and duplex hotspots, with dmr simplex nodes based on mobile radios and DMR repeaters.

With native digital repeaters it is less noticeable but irregularities are still present compared to listening with other DMR transceivers
(eg. Tyt MD390, Anitone 878, Retevis rt3.)

When I reinstalled the Open GD77 firmware, the problem came back again.

We noticed that even running the MMDVMCal utility in Pi-Star the problem occurs only with the open firmware.
(eg. DMR Simplex 1031Hz Test pattern)

Any idea about it?
Have other OMs reported similar problems before?

Thanks in advance for any information you may have about it.

73 '
Antonio IZ0MXY

P.S. I apologize for my bad English translation....

[YT5HOK]

...
We noticed that even running the MMDVMCal utility in Pi-Star the problem occurs only with the open firmware.
(eg. DMR Simplex 1031Hz Test pattern)
...

You addressed Roger, but if I may...

If you have cutouts with 1031Hz test pattern using MMDVMcal utility, then your devices are not on the same frequency, you should re-calibrate hotspots and even handhelds, as you said you have problems with repeaters too.

[IZ0MXY]

Every suggestion is useful and precious .....

the nodes used for the test are 3, the first with pi-star 3.4.17 mmdvm and Motorola GM350, in the 2 meter band
the second with pi-star 4.1.2, mmdvm and Motorola GM340 in the 70 cm band, the third with pi-star4.1.2, mmdvm and Yaesu FT897/D in 70 cm band,(in this case I can manually change the transmission and reception frequency)
The frequencies of the carriers measured with the frequency meter do not detect important deviations between the devices and nodes used and are in any case within tolerance.
The error rate always stays within the 0.5% range for all nodes and with all three GD77s tested on the two bands.

I also repeated tests with my duplex hotspot with mmdvm dual hat in 70 cm band, with even lower average error rates around 0.3% but even if in a less obvious way the problem occurs simply by switching from the original firmware to the modified one.
Surely the two firmware work very differently so I don't know exactly if for all the added features (an exceptional job) there could be some audio degradation.
I believe that the test set is easily replicable, using the Pi-star's MMDVMCal utility, I am (and we are) curious to know if other OMs have encountered this problem, (although perhaps we are looking for a nit)

Best regards from Rome to all the staff from iz0mxy Antonio and friends