OpenGD77

I perfectly understand that PA control is not trivial. Moreover, the manufacturer may have implemented tricks you did not think about or require hidden commands. For example, if you look at the image "RD-5R official firmware", you see a ramp-up of the PA before the DMR pulse. I intend to re-install ...

Edit: Please disregard this message, the spectrum analyser was probably saturated. This is the DMR modulation. First, the Baofeng: dmr_baof_150ks.jpg We still notice the spikes and they are a bit higher than in FM, relative to the signal. This is the GD77 with the open firmware: dmr_rad_150Ks.jpg I...

Edit: Please disregard this message, the spectrum analyser was probably saturated. This is difficult to analyse with a spectrum analyser, so take the following messages with a grain of salt. I noticed some erratic spikes on the GD77 with the open firmware when pressing the PTT. This is how it looks...

Increasing the spectrum bandwidth to 100 KHz allows us to understand what happens with the Baofeng. These are the pictures, taken without modulating signal: This is the GD77. fm_rad_100Ks.jpg This is the Baofeng. fm_baof_100Ks.jpg We notice that the Baofeng power amplifier adds spikes ever 10 KHz. T...

I tried that today. As I am not quite sure what kind of measurement you need, I was a bit in the dark, but maybe the results will be interesting. I had the Baofeng and the GD77 connected to a dummy load and transmitting with 1W. A quick test at 5W did not show much difference.A quick check with a na...

I do not own a spectrum analyser, apart from a TinySA, so I don't know if the spectral output with the OpenGD77 firmware is worse than the official firmware. I have a spectrum analyser. The output from the GD77 did not look much different that the output from other radios I tried. But if you tell m...

Roger, I am very grateful for your open firmware efforts. On my side as a user, I think I noticed a bug, so I am reporting it because I understood that this is what is wanted. I would appreciate if you could look into it, but I am not asking. If you tell me that you don't have the time now, I can wa...

I have access to a 100 MHz oscilloscope and I could indeed check the voltage levels. But the question was about interference and I don't really see how an oscilloscope would check that. Why do you say that the modulation is not good, how did you find out?

I can understand that. What kind of test equipment could be use to determine if there is interference? Would some kind of SDR do?

I would suggest looking at the output amplitude envelope with a diode detector or a fast scope. It sounds to me as if the RD5R is not controlling the output power fast enough and doesn't like the 30ms bursts. The bursts could be very distorted if the power rise time is slow. How would the original ...