Ryan's Blog
Sainsmart Ham Radio Hotspot.
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Introduction

Ham Radio Hotspots have gotten extremely popular. These hotspots allow an operator to connect to DMR, Yaesu Fusion, and D-Star digital networks without a local repeater nearby. Many operators build their own hotspot with a Raspberry Pi, though, recently, I obtained a Sainsmart Hotspot to try out these digital modes.

Information

The manual is hard to find. The key information found within the manual are:

  • Simplex repeater
  • Setting up the wifi
  • The radio hardware: STM32-DVM/MMDVM_HS-Raspberry Pi Hat (GPIO).
  • The LED setup info: OLED Type 3 / /dev/ttyAMA0 / G4KLX

Radio Firmware

Running pistar-findmodem is extremely important to figure out which modem is on your hotspot. Flashing the wrong firmware will leave the modem in a bad state, though reflashing the correct firmware appears to work.

# sudo pistar-findmodem
Detected MMDVM_HS (GPIO): /dev/ttyAMA0 (MMDVM_HS_Hat-v1.5.2 20201108 14.7456MHz ADF7021 FW by CA6JAU GitID #89daa20FF37066A3432434257012227)

My hotspot has the MMDVM_HS_Hat v1.5.2 14.7456 modem and firmware. MMDVM_HS_Hat comes in at least two versions: 14.7456 MHz or 12.288 MHz. Make sure to note which frequency is yours!

If you have an older version of the firmware it can be upgraded with:

# sudo pistar-mmdvmhshatflash hs_hat

Usage

Pi-Star allows for multiple digital modes to be enabled. This is a great feature since it allows us to leverage the different modes. On a simplex hotspot only one mode can be transmitting or receiving at a time.

Yaesu Fusion

Most Yaesu radios have built in Fusion or Wires-X buttons. The hotspot might not register the Wires-X button press, since it polls the modem for which mode (DMR, D-Star, or Fusion) it should be in.

I have found that keying up for around 1.5 seconds will set the YSF mode, and then pressing the Wires-X button will work. The RF Hangtime defaults to 20 seconds, and bumping this up to 60 seconds might be beneficial to some.

Problems

There is still an issue with joining a room. My FT-3D radio shows an FCS room when joining a YSF room. I opened a Github Issue to track it.