Update to the new v0.95 release
: https://github.com/DF4IAH/RedPitaya_RadioBox/releases/tag/RB_v0.95.01Find the updated app at the Bazaar
--- --- ---Thank you Rainer for asking for documentation. Here I bring up a list of further documentation
The RadioBox is a complete transmitter and receiver done in the FPGA. You can directly connect an antenna at the SMA RF In 2 port
for receiving. At the SMA RF Out 2 port you can listen to the demodulated signal.
The transmitter does it at the same time on the SMA In/Out 1 connectors. When an external SDR-software is desired, you can
select the Linux AC97 sound driver as stereo channels in both directions to feed the FPGA or to grab the data streams.
For connecting a SDR you can set the two AC97 channels to the I- and Q-signals of the modulation QMIXers. Feel free to test
To allow streaming from the Red Pitaya additional software packages are needed. A script for upgrading all needed stuff is called
by executing that shell script: /opt/redpitaya/www/apps/radiobox/bin/RadioBox_Upgrade.sh
.Additionally I give you a first starter, here:
When starting the application you can see a set-up that is organized into four big rows on the blue desktop.
- The Connection matrix connects all output lines (RF Out 1, RF Out 2 and the LEDs as scope) to any internal node you wish. Preset is to use RF Out 1 for
the RF signal of the transmitter, RF Out 2 is preset for audio output of the receiver. Feel free to re-arrange that mapping.
- Second row is the Transmitter section. Here you can set the carrier frequency on the left, select the modulation variant on the right side. The input line
you wish to use is just a field above. You are free to ship a modulation on any free ADC input channels (RF In 1 for audio speech microphone, RF In 2 is
preset for the receiver). Alternately you can enable the modulation oscillator to give a sine wave of any frequency and modulation strength / deviation.
- The Frequency row gives you a short-hand for entering frequencies into the TX or RX carrier frequency fields. You can either key in the frequency, or
you are free to up/down the digits for each one. With the help of the mouse wheel you can access these by another variant. Right of the dialer pad you
are able to do a automatic increase or decrease of the frequency. To stop the ride, move the slider to the middle position again. During frequency
incrementation / decrementation ("scanner mode") the modifiers for the frequency digits are blocked. Move the scanner slider to the middle position
to return control to the digits. Right of the frequency controller you find the two quick views of the transmitter and receiver.
- Last row the receiver is controlled here. On the right side select which ADC channel should be taken for the RF input signal. Also switch to the modulation
variant you desire. Switching to FM and PM gives loud noise when no carier is present, but that is no new information for a radio amateur.
With this short help you are able to play around. Beware that Red Pitaya output channels are designed to have a 50 ohms load at the port - or a matched
antenna. When that load is connected you can change the termination type of the output selectors to "50 ohms". This control makes sure, that no high
voltage swing comes out of the RF Out port when unloaded, especially where the frequency is around 17 MHz.
Have fun playing around. Feel free to connect a scope for checking modulation. Go low as 1 Hz if you wish. All mixers are multipliers, no condensor takes
you the freedom to go that low in frequencies.
In the first row, the Connection matrix, you can enable the LEDs on the Red Pitaya board to give a simple "scope". The amplitude is logarithmic that
allows for a wide range of signal amplitudes to be shown. To minimize RFI the high speed signals for the LEDs are turned to low frequenies first.
I would love to hear, if students are willing to play and learn about modulations. Which HAM operators will have the first QSO between two RedPitayas?