Saturday, December 8, 2018


SVT MMDVM first calls

The Digital Voice ( DV ) for the ham radio have started a few years ago but to build a hotspot ( a tiny personal half duplex repeater ), you will need some pricey equipments like DVStick with AMBE-3000 vocoder and USB interface plugged into a Raspberry Pi with an Arduino Mega to drive the UHF transceiver. 

It all started around Sept 2017 when the price of DMR radio was getting below RM1,000 and a few of us purchased a TYT MD-2017, one of the more popular DMR radio at that time.

Secondly, without a DV hotspot, having a DMR radio is kinda useless unless you are within the range of a DMR repeater in your area.


Thanks to Jonathan Naylor G4KLX ( ) (and many many people people) that created the MMDVM, a software that integrated multiple hardware ( teensy, Arduino DUE, STM32F1, STM32F4 ) and Raspberry Pi running pi-star ( ).

When I saw the hardware requirements, I noticed that I actually have ALL the hardware with me, STM32F103 red-pill, Raspberry Pi and they were also using a version of Arduino called stm32duino

A few STM32 red-pill I purchased previously

The only missing piece was the UHF transceiver called RF7021SE module plus changing the TXCO to 14.7456Mhz. So I started doing my research on different board designs and immediately design a single board layer to test out my design.

MMDVM boards

MMDVM boards

Here is the first version after many iterations and because it was a single layer board, I had to place the SMD LED at the bottom of the board.



Once my designed was almost finalised, I bring it to Uncle Chow ( 9M2CF ) to convert my PCB design to a single layer PCB.

SVT MMDVM negative

SVT MMDVM etched

SVT MMDVM copper removed

After some UV exposure and chemical baths, I got the SVT MMDVM board ready to be soldered.

SVT MMDVM fully soldered

SVT MMDVM top side with red-pill

SVT MMDVM running

Fully connected to the RPI 1 and pi-star software loaded.

SVT MMDVM connected to RPI 1

1 comment:

  1. Hi Bro, I've PM you on FB trying to learn more on DMR and MMDVM hot-spot but could not really understand it. I've purchased a dmr by anytone few days back.hope you can help me understand it better and to have a hotpot at home.