Radioberry QRP

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Feb 14, 2021, 6:42:26 AMFeb 14
to Radioberry

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!

Some specs:

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.

External connections:

- 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.

RPI setting:

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?

Have fun

73 Johan


development process... sometimes hard for someone who is colorblind....

radioberry_preamp -1 (1).jpg

radioberry_preamp -3 (1).jpg

pa running.JPG

PA protection.... also visible in the log!

PA temp.JPG


Apr 2, 2021, 1:06:40 PMApr 2
to Radioberry
Hi Johan,
Congratulations for your beautiful board.
i have just ordered PCB, fro JLPCB.
For your opinion which is the best solution for mechanical connect the board ? I it will be stacked maybe there is no enough space for heat dissipators.
Con you please share your current solution?
Do you have  found a suitable enclosure?
Luca IK2LRN 
Milano Italia


Apr 3, 2021, 8:05:51 AMApr 3
to Radioberry
Hi Luca,

Nice you are planning to build the board. Have fun.

From Steli AE6OR i got the following link for a case:

Also sharing a picture from his setup:


i have not make a final setup.

Hope this helps.

73 Johan 

Op vrijdag 2 april 2021 om 19:06:40 UTC+2 schreef
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