I think the OpenGD77 Hotspot mode firmware is probably stable enough for more people to Beta test it, so I am making it publicly available for download.
Since I’ve now pushed all the source code to GitHub, I’m also updating my “Daily builds” version on github.The latest version of the complete OpenGD77 firmware, including Hotspot mode, can be downloaded from here
This version also has some new features to the non-hotspot use of the firmware, including audible Timeout warning beeps, and DMR audio mute, for use when you only want to receive Private Calls
This firmware can be loaded onto the GD77 using the official firmware loader.
- This firmware is still in the early stages of development.
- It only supports DMR audio. i.e It does Not support SMS messages at the moment, and won’t support SMS until after Tier 2 functionality is working, as Tier 2 is our priority for our development time.
- You use it at your own risk.
- It may not be completely stable and is likely to have bugs.
- Using high power settings may overheat the PA in the radio, because the radio is not designed to be constantly transmitting.
- There is a potential bug where Tx does not turn off. So the hotspot should not be left unattended for extended periods
Default power in the OpenGD77 firmware is approximately 1W, and this is the value that will be used by the Hotspot unless you change either the Power (PA drive) value in the Utilities menu, or you change the RF Level setting in PiStar’s Expert -> MMDVMHost settings.
If you change the power setting in PiStar to any other value apart from the default value of 100%, the firmware will use the value from PiStar.
Hence 99% will give almost 5W, which is unsustainable over a long period of time.
0% will almost turn the PA off completely, but you will find at short distances that the 5mW produced by the AT-1846S Tx/Rx chip in the GD-77 can still be received.
The power display in Hotspot mode, is currently only a rough approximation of power, as its actually the percentage of PA drive, multiplied by 5000mW to give a mW figure.
However since the PA output is non linear with respect to PA drive voltage this value is not accurate.
If you want to set your Hotspot to a specific power level, which you measure using your own power meter.
- Turn off PiStar (Power off)
- Exit from Hotspot mode using the red menu key.
- The radio will probably now be in VFO mode.
- Connect a power meter
- Press the * button and look at the top left of the display to confirm the radio is in FM mode (or press * again until you toggle into FM mode)
- Go into the Utilities menu, and select a PA drive setting (approx 1700 gives 1W)
- Adjust the value by pressing the left and right buttons.
- Press the PTT to transmit in FM and confirm the power level
- When you are happy with the power level. Press the green menu key.
- Turn the GD77 off and on again, go back into the Utilities menu and confirm the power setting has been saved
- Exit back to the VFO (or Channel screen) by pressing the green menu key.
- Turn PiStar back on, and wait for the radio to enter Hotspot mode.
- Make sure the RF level is set to 100%, as this will use the value you just assigned in the radio