A week after receiving my DV4 Mini dongle I thought it would be helpful to give a review and my experiences with it.
Firstly, a note of caution if it is intended to use the dongle with a PC running Windows XP - Helitron don't recommend using XP, even though they supply software, and I can confirm that on two of my XP equipped laptops the software isn't suitable. It works fine on Vista and above but I have found the most reliable platform is via a Raspberry Pi.
The control software is good and easy to follow, and is relatively straightforward to use. It gives options for power levels and which server to connect to as well as giving a display as to which reflector you are connected to and the traffic through.
On the Pi (and Windows Vista on) the dongle needs no drivers as it is automatically recognised (with XP a driver has to be downloaded - although I haven't been able to run the software on XP).
As a result of monitoring and using the DV4 Mini, I have observed that users accessing via Dstar have good connection and superb audio, and Fusion users have reported that it works very well on that system. DMR is a different matter though. The connection suffers from drop outs and missing syncs, which makes the use of the dongle very challenging. I have used various methods to try to address these problems; low power on the handheld, wrapping the dongle in foil and using an external antenna and siting it well away from the dongle to minimise excess RF getting to the dongle, but it would seem that these measures haven't improved matters much; which leads me to believe that the software needs some attention. Fusion and Dstar users report that it works fine. I have investigated my Internet connection and although connecting via wi-fi is ok, a direct connection through an ethernet cable is marginally more reliable.
So, my conclusion is :-
Very good idea and it works reasonably well. Software glitches need to be sorted for DMR use and once these are addressed the whole experience will be improved. It's early days for the DV4 Mini and I'm sure that the Amateur Radio Community and the software developers will work towards a solution - let's hope that it comes soon.