This is an attempt at making a 70cm DMR repeater which supports VoCoders AMBE+2 and Codec2. It will also support connecting to the Brandmeister DMR network.
Second attempt:
Will be with two Analog devices IC's ADF7021 and a 12.2880Mhz +/- 1ppm TCXO
ADF7021 module cards from Aliexpress: Aliexpress link
First attempt:
The first version is an experiment model with Silicon lab Si4463 for RX and TX. The modules with Analog devices ADF7021 is connected to a Raspberry Pi 3.Si4463 Module: Aliexpress...
Si4463 is not suited for DMR since it does not have the possiblity to make an RRC-filter on Tx. I also need to use a PLL refrence wich has at +/- 1ppm stability!
I found out which RF IC I need, its the ADF7021 from analog devices and also a 12.2880Mhz +/- 1ppm TCXO from Golledge in the UK
Started writing some more code just for using one module to test the code a bit.
Did hookup one module to Raspberry Pi 3:
Managed to get SPI communication up and running with one Si4463 RF IC.
Hookup with one radio module to Raspberry Pi 3| Si4463 module | Raspberry Pi 3 |
|---|---|
| 1, GND | 6, GND |
| 2, SDN | 18, GPIO24 |
| 5, nSEL | 16, GPIO23 |
| 6, MOSI | 19, MOSI |
| 7, MISO | 21, MISO |
| 8, SCK | 23, SCK |
| 9, IRQ | 13, GPIO27 |
| 12, VCC => +3,3VDC | 1, +3,3VDC |
73&88 de LA7LKA