OpenHPSDR

Lore & Background

The OpenHPSDR project began in 2005 when Phil Covington, Phil Harman, and Bill Tracey merged their separate efforts into a single group. The design is centered on a modular concept, allowing users to experiment with techniques such as SDR and Envelope Elimination and Restoration without replacing the entire hardware set. The project has expanded beyond the original founders, with several additional people contributing to recent module designs.

The core modules consist of the Atlas passive backplane, the Ozy interface providing a USB 2.0 data channel between the system and a host PC, and the Mercury and Penelope receiver and exciter boards. Mercury uses a 16-bit 135 MSPS analog-to-digital converter, offering performance from DC to 55 MHz comparable to conventional analog HF radios. It can also operate in VHF and UHF ranges using mixer image or alias responses. The host computer processes the digital bitstream using DSP techniques, and the hardware has been interfaced with the Flex-Radio PowerSDR Windows-based software, which is licensed under the GPL.

As of February 2011, released modules include the Atlas backplane, Magister control board, Janus I/Q interface board, Mercury receiver, LPU linear power supply, Pandora enclosure, Excalibur frequency reference board, PennyWhistle 20 watt amplifier, Hercules 100 watt amplifier, and Metis 1 Gbit PC interface board. Modules nearing release include the Alex RX/TX filter bank. The Ozy USB control board has been replaced by Magister, and the Penelope exciter has been replaced by PennyLane, which is provided by a new commercial organization rather than TAPR.

Reader's Guide

The OpenHPSDR project's significance lies in its modular, open-source approach to software-defined radio, which has enabled a community of experimenters to explore advanced techniques without needing to replace entire systems. The project's hardware, provided in cooperation with TAPR, has been made available as assembled units, bare circuit boards, or kits, fostering broad accessibility. The Mercury receiver, with its 16-bit 135 MSPS ADC, demonstrated that direct-sampling SDR could match the performance of conventional analog HF radios, while also offering VHF/UHF operation through alias responses. The project's open-source software licensing and use of the GPL-licensed PowerSDR software have encouraged collaborative development. Several complete transceivers, such as the Anan-10, Anan-100, Anan-100D, Anan-200D, Anan-7000DLE, and Anan-8000DLE, have been built upon the OpenHPSDR concept, indicating its influence on commercial and hobbyist radio designs. The modular architecture, with modules like the Atlas backplane and Metis interface, allowed incremental upgrades and experimentation with new devices, such as Envelope Elimination and Restoration, without obsolescence of existing boards.

Did You Know?

• The Mercury receiver uses a 16-bit 135 MSPS analog-to-digital converter for direct conversion from DC to 55 MHz.
• The Ozy USB control board was later replaced by the Magister control board.