I have been casually using DMR, D-STAR and YSF (Yaesu System Fusion) modes for a couple of years, using a ZUMSpot. The ZUMSpot is a small board that sits on a Raspberry Pi Zero W. It incorporates a Multimode Digital Voice Modem (MMDVM) and a 10mW UHF transceiver that operates YSF, DMR, YSF2DMR, D-Star, P25 and NXDN modes. The ZUMSpot uses Pi-Star digital voice software. Pi-Star is a custom, pre-configured SD Card image for the Raspbperry Pi, with configuration and operation performed through a web browser. The Amateur Radio Notes website has an excellent tutorial on setting up and configuring Pi-Star. While the Pi-Star configuration appears daunting at first, it is easy to set up by following the tutorial. There are also several videos on YouTube with instructions for configuring Pi-Star.
A few days ago, I was attempting to update the Pi-Star software and the ZumSpot firmware, but kept seeing errors during the firmware update. After several attempts to update the firmware, the ZumSpot wasn’t operating properly*, so I decided to purchase an openSPOT 3, which is made by SharkRF in Estonia.
The openSPOT3 is a battery powered, portable, standalone digital radio internet gateway (aka hotspot). The openSPOT 3 is also configured through a web interface, but the interface and steps for configuration are different than Pi-Star’s. The openSPOT 3 user manual is a web page that is updated frequently when there are firmware updates or features added to the device. Having learned the basics of DMR, D-STAR, and YSF with the ZUMSpot, I found configuration of the OPENSpot 3 to be fairly easy.
* After I had the openSPOT 3 up and running for a few days, I decided to attempt the ZUMSpot firmware upgrade again. It turns out I had missed a step in my earlier attempts, and this time the update was successful. So now I have two MMDVMs!
Both the ZUMSpot and OpenSPOT 3 are excellent MMDVMs. Both are capable of operating the most popular digital voice modes using a DMR, D-STAR or C4FM radio. Also, they both require a wi-fi connection and are configured through a web interface. The openSPOT 3 is great for portable operations since it has a built-in battery and the configuration web page works very well on a mobile phone web browser. Since the ZUMSpot is based on a Raspberry Pi Zero W, it could also be used portable with a USB power bank. The openSPOT 3 costs a bit more more than the ZUMSpot. There are also many other MMDVMs on the market, including inexpensive generic boards and kits available on Amazon and eBay. Digital voice modes with MMDVMs are a great way to talk to hams from all over the world using a VHF/UHF digital radio and an Internet connection.