Radioberry preamp board.
This board is a nice addition to turn the radioberry into a small QRP radio.
The design is based on all the amazing work of Hermes Lite 2 Group!
Power in : 12V
HF Power in : Tx from radioberry.
HF Power out: 5W
The board (2-layers) must be plugged on top of the radioberry.
- DASH/DOT for CW using pihpsdr.
- External PTT
RX/TX Switching is done using a relais.
I do use this board with my power amplifier (100 W) using built in LPF filters.
The board contains 2 fets for getting the HF power.
Furthermore the board contains two i2c sensor devices.
MCP4662 Dual digital potentiometer.
This device is used to set both bias settings for the Radioberry preAmp.
The setting can be made permanent (non volatile) by saving the bias values in the EEPROM of the device.
The bias is a specific setting stored and determined specific per preAmp board. (Setup only once).
MAX11613 4 Channel Slow ADC
This device is measuring:
- the temperature of the PA finals
- the PA current during transmit.
The temperature and current are visible in the SDR program.
Control the PA by gateware and firmware:
- the bias voltage and power supply (swith the PA on/off)
- switch off the attached power amplifier if the current and temp could not be measured.
- supports the setting of the pa bias setting
- if temperature of PA is higher than 50C; PA will be switched off!
- PA recovery after high temperature; switch PA on again if PA temp is in range for 10 seconds.
The control of the i2c devices is not done by the gateware as done in the HL-2 but in the firmware
by use of the i2c module running on the RPI, so the i2c module must be selected.
Connecting the board (12V is not required to connect) and by opening a command window
it is possible to detect the attached devices: sudo i2cdetect -y 1
Radioberry Software Changes:
To support the board I have changed the gateware, firmware and device driver. Need to update github and make a release.
Update of wiki is also required.
I have some assembled boards available please let me know if you are interested?
development process... sometimes hard for someone who is colorblind....
PA protection.... also visible in the log!