RadioBox - the radio amateur's toolkit for RF

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Posts: 6
Joined: Mon Feb 29, 2016 1:12 am

Re: RadioBox - the radio amateur's toolkit for RF

Post by DJ6OA » Fri May 20, 2016 9:00 pm

Hello Uli,

Seems to be a very interesting project, but is there any documentation for dummies how to connect to the audio input and output system or program, and to operate the whole thing, preferably on a Linux system?

Some hints would be helpful.

Thanks in advance

73, Rainer, DJ6OA

Posts: 14
Joined: Thu Aug 20, 2015 12:19 am
Location: JN49HL / Germany nr. Heidelberg

Re: RadioBox - the radio amateur's toolkit for RF

Post by DF4IAH » Sat May 21, 2016 1:54 am

Update to the new v0.95 release: ... B_v0.95.01

Find 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/
  • when starting RadioBox, you get two quick views in the height of the frequency dialer. The redish one is for the transmitter part,
    the greenish one for the receiver. Simply press those big buttons, to open a bigger view of these overview map. I am sure you see
    the know parts of a receiver and/or transmitter, where mixers are named QMIX ("quadrature mixer").
  • more details of the project is found at the Wiki of RadioBox, which you find here:
  • find even more details which data path for each modulation variant is taken on my Dropbox folder for all releases: ... 663Za?dl=0
    Step into the release directory and go ahead to the docs directory. There you find much more file entries about the RadioBox application.
  • for programmers a detailed FPGA RadioBox register set documentation is found within the radiobox directory called RedPitaya_RadioBox_Development_Manual.pdf.
    I post the link to that document here: ... Manual.pdf

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.
  1. 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.
  2. 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.
  3. 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.
  4. 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?
Have fun! :D

Vy 73
Uli, DF4IAH.


Posts: 14
Joined: Thu Aug 20, 2015 12:19 am
Location: JN49HL / Germany nr. Heidelberg

Re: RadioBox - the radio amateur's toolkit for RF

Post by DF4IAH » Fri Jul 15, 2016 8:42 pm

The latest news about RadioBox:
  • UPDATE RadioBox application at the bazaar:
  • find more information about RadioBox on the Red Pitaya:
  • receiver part includes AGC (automatic gain control) at three sections:
    1) at the input equalizer,
    2) in front of the IF mixer,
    3) at the SSB decoder stage
    resulting into an equalized receiver without over- und underruns of each stage giving brilliant sound. Give it a try! ;)
Have fun with the free RadioBox app!


Posts: 4
Joined: Mon Jan 02, 2017 8:52 pm

Re: RadioBox - the radio amateur's toolkit for RF

Post by videticj » Mon Jan 02, 2017 8:53 pm


Is there an easy way to input the carrier signal from an RF input?
I have a unique application where I want a ~70Hz FM tone at a fixed amplitude and want to step the carrier frequency.


- John


Posts: 7
Joined: Mon Feb 22, 2016 12:01 pm

Re: RadioBox - the radio amateur's toolkit for RF

Post by TECH_DD » Wed Nov 22, 2017 6:35 pm

Bulova wrote:Hello Uli,

now I finally found the time to manage it and -- had fantastic success! RadioBox works great. I tested i. e. 1 MHz carrier and 1 kHz AM with 80 % grade. You certainly could imagine, what this is for. Yes, it is for EMC test. It would be very good to complete a functionality, where you can go frequency steps of 1 % and with a set time delay. This is for testing and observing the influence to a probe (EUT). It is not possible to go up to 80 MHz with RP, but at least to 50 MHz.
I will test the RadioBox for some more functions.


Hi Bulova, can you explane how is composed your test equipment please? I mean: do you use an amplifier? How kind of coupler network do you use? I'm very interesting to do some pre compliance test with my redPitaya. At the moment I try to find a good results on the Conducted Emission regarding the EN 55011 standard, I try to use a LISN and the Spectrum Analizer App.

Thank you in advance! :D

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