Amateur radio firmware for the GD-77, GD-77S, DM-1801, DM-1801A, RD-5R, MD-9600/RT-90, MD-UV380/RT-3S, DM-1701/RT-84 and MD2017/RT-82 radios
https://www.opengd77.com/
This change is now in the "latest" released version, http://opengd77.com/viewtopic.php?f=13& ... 5e3bb69723
Thanks a lot Roger!VK3KYY wrote: ↑Sat Feb 22, 2020 6:54 amThis change is now in the "latest" released version, http://opengd77.com/viewtopic.php?f=13& ... 5e3bb69723
which also has 1 or 2 other fixes.
Google translator -->EB2EAS wrote: ↑Sat Feb 22, 2020 11:43 amBuenos días Roger.
No sé si será interesante pero he incluido en el menú de opciones el que se pueda modificar este dato. Las pruebas que he realizado son satisfactorias. Así la gente podrá modificar el valor sin cargar un nuevo firm.
Un saludo de EB2EAS José.
EB2EAS wrote: ↑Sat Feb 22, 2020 11:43 amGood morning Roger.
I do not know if it will be interesting but I have included in the options menu the one that can modify this data. The tests I have done are satisfactory. This way people can change the value without loading a new firm.
Greetings from EB2EAS José.
This change happened over 6 months ago. But from what I can remember the change was the number frames which needed to enter the audio buffer before the audio decoding, and hence the audio output would start.EB3AM wrote: ↑Sat Oct 17, 2020 8:12 amHi, up this post momentarily so it's easier to know what I'm talking about.
I've been playing with GD77 for the area I live in, full of mountains. We now have a major network of DMR repeaters, but the orography means that we do not always have them in reach. As you know, the DMR requires a little more signal level than the FM to start decoding audio.
Well, if I remember correctly, a margin of 390ms (13 frames) was left to lose synchronism.
Can an experimental firmware be made with a switch where this time can be increased?
During the February tests it was seen to be enough, but I think a higher time would help in mountain areas.
How about that?
Hi Chaps. I have found the posts that I was referring to but do not understand how I am able to implement this.. My GD77s use a firmware version Mar 4 2023 efc2c8b D . Have the firmware versions since these posts include the alteration to improve the dmr receive side. Can this timeout be adjusted or what please ? 73 de Les G0FAJVK3KYY wrote: ↑Wed Feb 19, 2020 9:48 pmG4EML wrote: ↑Wed Feb 19, 2020 9:39 pmI am currently running with a timeout of 13. No issues so far.
It is still only a third of a second. Fading and flutter can easily cause dropouts of that sort of duration.
I would expect some audio artifacts in that situation but it would recover instantly the signal returns. The AMBE Codec is pretty good at handling data errors so the resulting audio would be a lot more usable than having total dropouts.
The problem with low values is that the code drops back to DMR_STATE_IDLE. When the signal returns it has to re-establish the timeslot timing and go through the late entry process, both of which take time.
We probably need to tune this value for Ham radio use.
E.g. for very weak signals, perhaps an even larger value could be better. But there will probably be disadvantages to both large and small values
This thread releates to a post I made in 2020, so the information in it is totally obsolete.