Some problems were found by several people with the initial test version 0.0.7 so all testers should update to the latest version 0.0.71 and retest
Some, but not all problems that people reported seem to be associated with the host sending Tx and Rx frequencies which were not the same.
This caused the underlying DMR subsystem to think the radio needed to operate in Tier2 Passive mode, like it does when connecting to repeaters.
A legacy of how the official codeplug works, there isn’t a parameter in the Channel data which specifies whether the radio is communicating with a repeater in in Tier2 Passive (semi duplex), or Tier2 Active (simplex operation).
The firmware can only check whether the Tx an Rx frequencies are the same or different, and if they are different the DMR subsystem is put into Tier2 Passive mode (where the repeater is the synchronisation master) and if the frequencies are the same, it goes into Tier2 Active mode (where the GD-77 is the synchronisation mater)
Strangely some programs like BlueDV seem to send Tx and Rx frequencies which have small offsets e.g. 7Hz in one case, but PiStar can also do the same thing, as there seem to be rounding errors in the calculations somewhere in the host system.
You may have noticed sometimes in PiStar, especially with Duplex hotspots, if you enter a frequency eg 439.125 but the page updates and you find the frequency has changed to 439.1249999 . And this casued a problem for the OpenGD77 firmware
Some of the problems in the host software, seems to come from the way frequency offsets are handled. The MMDVMHost communication protocol does not have a way to send the offset frequencies, but instead it simply adds the offset (or subtracts for negative numbers), the offset frequency from the main frequency, and sends the resultant frequency to the hotspot.
This is regardless of which type of hotspot you use.
But this does not cause a problem on the normal simplex hotspot boards, as they only ever operate in simplex mode and analyse the frequencies they are sent.
Anyway. The fix I have put into version 0.0.71 is to take the average value of the Tx and Rx frequencies that are sent by BlueDV or PiStar and use that for both the Tx and Rx frequency.
In the longer term, I probably need to overhaul the DMR subsystem so that the Tier2 mode (Passive or Active) can be controlled separately from relying on comparing the Tx and Rx frequencies, but thats a much bigger change and would potentially cause bugs in the normal operation of the radio.
There was another potential problem where the Rx bandwidth filters could potentially be left set to 25kHz of the radio was on a channel with that bandwidth prior to hotspot mode being entered, so I’ve also fixed that problem in version 0.0.71
I know that 0.0.71 does not fix the problems for everyone, but I’d advise all testers to update to the Tier2Latest as it definitely fixes 2 potential causes of problems
I will simultaneously be rolling out other fixes in next few days, but hopefully they won’t impact on the Hotspot mode functionality