Opera Cake is an antenna switching add-on board for HackRF One that is configured with command-line software either manually, or for automated port switching based on frequency or time. It has two primary ports, each connected to any of eight secondary ports, and is optimized for use as a pair of 1x4 switches or as a single 1x8 switch. Its recommended frequency range is 1 MHz to 4 GHz.

When HackRF One is used to transmit, Opera Cake can automatically route its output to the appropriate transmit antennas, as well as any external filters, amplifiers, etc. No changes are needed to the existing SDR software, but full control from the host is available.

Opera Cake also enhances the HackRF One’s use as a spectrum analyzer. Antenna switching works with the existing hackrf_sweep feature, which can sweep the whole tuning range in less than a second. Automatic switching mid-sweep enables the use of multiple antennas when sweeping a wide frequency range.

Documentation + Technical Information

For open source design files, visit the Opera Cake hardware directory in the HackRF github repository. For documentation, visit the Opera Cake page on Read the Docs or view the raw documentation sources in the docs folder in the HackRF repository.

Getting Help

The answers to many general questions about Opera Cake use and development can be found in the HackRF manual on Read the Docs.

If you still need assistance after browsing the documentation, please visit issues on the HackRF GitHub project. This is the preferred place to ask questions so that others may locate the answer to your question in the future.

Join the Great Scott Gadgets community discussions on Discord. Note that while technical support requests are welcome there, they do not have support staff on duty at all times and your questions are not guaranteed to be answered. Be sure to also submit an issue on GitHub if you’ve found a bug or if you want to ensure that your request will be tracked and not overlooked.