I will solder some more wires to my GD77 "test" board today, to capture the data sent to the AT1846S RF chip during DMR Tx.do1jml wrote: ↑Sat Feb 20, 2021 10:34 pmIf I understood correctly, only the GD77 has separate PA for VHF and UHF. The GD77 works reasonably well when using the open firmware, therefore the correct PA is most probably used. If the wrong PA was used, we would not get reasonable results as to spectrum and power, yet we do.
There are still some finesses that need to be found out, as: "why does the ticking sound disappear when using the manufacturer's firmware on the same radio?", but they are relatively unimportant.
Again, if I understood correctly, the RD-5R uses one PA for the whole band. Yet, the open firmware does not work optimally on that radio. The power level is lower than expected and the spectrum adds spikes. The manufacturer found a way to operate the hardware which you did not find out.
(This is not easy...)
Its possible that the official firmware controls some other values during DMR Tx.
Re: Ticking sound on the RD5R
This is probably caused by bad regulation of voltages in the radio, but somehow the official firmware limits the change to current and hence limits the noise because of bad voltage regulation.
PS. I think there is a schematic online for the FM radio which we think is similar to the RD5R, but I can't remember the model number of that Baofeng radio.
I will look on the github issues to see if I can find the name that the Russian Ham said was a similar (non DMR version)