My first hotspot was a ZUMspot from HAM Radio Outlet, which I bought in Plano,TX. Well it is a PI-Zero in a nice housing, running in simplex mode and has a small OLED display. It worked fine at the beginning but for whatever reasons (never investigated deep into it) it became unstable. As I had to Raspberry 3B at home I ordered two china-made Dual-Hat MMDVM’s for the pistar software. They run much faster and quite unproblematic and in Duplex mode. My setup here is that one Hotspot run’s DMR, the other DStar with the latest pi-star beta-software. The DStar one has an OLED display the DMR one has a colour Nexion display which needs a bit more attention in terms of configuration and preparation for this job.
The latest hotspot I bought is the SharkRF openSPOT3 which plays in a much higher league than the MMDVM ones, as it starts within 5 sec. has a build in lithium battery which is nice in the car, cause starting the car always takes for a short moment the power away and the raspberries do not really like it (use a power-bank in this case).
The MMDVM is quickly installed to the raspberry pi, the only soldering work are the antenna sockets which have to be soldered on the PCB and maybe the connectors for the displays. The OpenSPOT3 comes ready made and needs some easy configuration, much easier than the pi-star software.
If you want to know much more about hotspots, try this website, it gives you tons of information. In addition the pi-star website maintained by Andy Taylor (MW0MWZ). Information about the openSPOT3 can be found at the SharkRF website.
I will not dive deeper into the technology or configuration of hotspots, as there are thousands of excellent articles about it in the internet – google is your friend.
Hotspots are ideal if you have antenna restrictions, or you are on the road and do not want to have a repeater list for your whole country or state in the radio, you are in a hotel, clinic or too far away from a repeater. Together with your mobile in tethering mode (mobile is set to WLAN access point) or you have a small LTE/WLAN Router, these hotspots are simply great. Especially the SharkRF one, as it can bridge by hardware transcoding automatically with the built-in AMBE® vocoder chip to other technologies for instance to DMR from C4FM, DStar and vice versa.