By Hadrian - YO2BTW 
Hermes Lite 2 is a compact, affordable, and highly regarded Software Defined Radio (SDR) transceiver within the amateur radio community. It was designed to deliver decent performance in a cost-effective format and is inspired by the original Hermes transceiver, though it uses a simplified architecture and more accessible components. Here are some key details:
Main Features
- Frequency Range: Covers HF bands (0–30 MHz), making it suitable for traditional HF applications.
- Output Power: Delivers about 5W of output power, making it an ideal QRP (low power) transceiver for outdoor operations or for enthusiasts seeking to minimize power consumption.
- SDR Technology: As an SDR-based transceiver, signal processing is largely handled through software. This allows it to be extremely flexible and easy to upgrade.
- Open-Source Software Compatibility: Works well with programs like OpenHPSDR and other compatible applications, enabling users to experiment with various operating modes and customize the interface.
Advantages
- Affordable Price: Much cheaper than most SDR transceivers of similar performance, making it an ideal choice for amateurs wanting to explore SDR without a major investment.
- Compact Size: Due to its minimalist design, it’s easy to transport and install in tight spaces.
- Easy to Assemble and Use: Many enthusiasts prefer it because it’s easy to set up and doesn’t require special equipment to operate.
Disadvantages
- Limited Output Power: With only 5W, it is more suited for short- to mid-range communication or working with efficient antennas.
- Simplified Interface: Some advanced functions found in higher-end transceivers may not be available.
Usage
Hermes Lite 2 is ideal for amateur radio operators who want to learn about SDR and for those interested in QRP operations. Thanks to its compatibility with open-source software and a large user community, it is a great choice for experimentation and custom projects.
If you’re interested in trying out an affordable and user-friendly SDR solution, Hermes Lite 2 can be an excellent option.
History
Hermes Lite 2 was designed by a small team of engineers and passionate radio amateurs, coordinated by Steve Haynal (KF7O). The project started as a simplified version of the original Hermes transceiver developed within the OpenHPSDR project, which aimed to create open-source SDR equipment for amateur radio.
Development History
The idea behind Hermes Lite 2 was to offer a performant but affordable SDR transceiver without the complexity and high costs of advanced SDR equipment. To achieve this, Steve Haynal and his team reduced the initial functionality of the original Hermes transceiver, making it more suitable for users looking for a simple but capable device.
The first version, Hermes Lite 1, was launched in 2016, and its success led to the development of the improved Hermes Lite 2. This version brought significant enhancements in performance, stability, and software compatibility, quickly becoming popular among amateur radio enthusiasts looking for an affordable and customizable SDR transceiver.
Open-Source Nature and Community
Hermes Lite 2 is part of a tradition of open-source SDR equipment, and its development has been influenced by user feedback and volunteer contributions. Since both the hardware and software are open-source, many independent developers and radio amateurs have contributed to improving the operating software and creating additional functionalities.
This model continues to benefit from community support, which actively contributes to optimizing and adapting related software such as OpenHPSDR and other compatible applications. In this way, Hermes Lite 2 has become more than just a transceiver – it’s also a learning and experimentation platform for radio amateurs interested in SDR.
Development Team
Although Steve Haynal (KF7O) is the lead developer, Hermes Lite 2 has also benefited from contributions by other enthusiasts and developers in the amateur radio community. The team collaborated closely with engineers, hams, and software developers worldwide, managing to deliver a high-quality, affordable, and versatile product to the community.
Thetis Compatibility
Hermes Lite 2 also works with Thetis software, a variant of PowerSDR specially developed for SDR platforms compatible with OpenHPSDR, including Hermes Lite 2. Thetis offers a modernized interface and improved functionalities compared to PowerSDR, and is optimized to work well with Hermes-based transceivers.
With Thetis, Hermes Lite 2 users gain access to advanced DSP settings, configurable filters, multi-mode operation features, and tools for detailed signal monitoring and control. This software enables you to fully leverage Hermes Lite 2’s SDR capabilities and enjoy a much more flexible and interactive operating experience.
Setting up Thetis with Hermes Lite 2 requires some specific configurations to optimize connection and synchronization, but there are detailed guides and user communities that offer support for proper integration.
Differences Between PowerSDR and Thetis
PowerSDR and Thetis are both popular programs for operating SDR transceivers compatible with OpenHPSDR, but there are several key differences between them in terms of interface, features, and software optimizations:
- User Interface
- PowerSDR: Has an older, simpler interface with basic features, still sufficient for SDR operation. It’s easy to use but lacks modern graphic design.
- Thetis: Offers a more modern and visually pleasing interface with refined design and graphic improvements. It is more flexible and customizable, allowing users to adjust layouts and better visualize the spectrum and waterfall.
- DSP Performance and Optimization
- PowerSDR: Optimized for older hardware, but its DSP is less advanced. Signal processing is good but somewhat limited in filtering and noise reduction.
- Thetis: Uses more advanced DSP algorithms, providing better noise filtering and improved signal clarity. Thetis delivers clearer audio and quicker response times.
- Stability and Hardware Support
- PowerSDR: Stable and mature software, but no longer actively developed, so it lacks support for newer hardware.
- Thetis: Actively developed by Apache Labs and the OpenHPSDR community, allowing for frequent updates and support for modern SDR devices like Anan and Hermes Lite 2.
- Advanced Features
- PowerSDR: Includes basic features needed for SDR operation, with limited advanced options.
- Thetis: Adds advanced features like real-time spectrum monitoring, sampling rate control, and detailed audio signal processing (AGC, equalizer, etc.).
- SDR Compatibility
- PowerSDR: Mainly compatible with older SDRs like FlexRadio and early HPSDR models.
- Thetis: More flexible and compatible with most modern OpenHPSDR-based SDRs like Anan and Hermes Lite 2.
Conclusion: Thetis is a more modern and powerful option than PowerSDR, offering a more advanced and enjoyable user experience. It is recommended for users with newer compatible SDRs who want to benefit from advanced DSP capabilities and a more attractive interface.
Thetis – Development History
Thetis was developed by Apache Labs in collaboration with the OpenHPSDR community, which played a key role in creating software for high-performance SDR transceivers. Thetis is a continuation and modernization of the PowerSDR software, initially created by FlexRadio, but adapted and improved for HPSDR-based platforms such as Anan and Hermes Lite.
The OpenHPSDR community, composed of radio amateurs and engineers, actively contributes to Thetis by fixing bugs, optimizing DSP functions, and adding new features. This open and ongoing collaboration ensures that Thetis remains relevant and up-to-date for modern amateur radio needs.
Thetis was developed by Apache Labs with a small team of engineers and volunteers from the OpenHPSDR community. While there’s no official development team list, it is largely supported by independent developers and hams worldwide.
Key contributors to SDR architecture in the HPSDR community include Phil Harman (VK6APH) and Warren Pratt (NR0V), who helped improve DSP algorithms. Apache Labs, as a hardware provider for compatible platforms (e.g., Anan), also contributes to Thetis support and development.
The OpenHPSDR community is made up of numerous volunteers, many of whom are amateur radio operators who continually improve Thetis features and provide support for updates.
Manufacturing of Hermes Lite 2
Hermes Lite 2 is mainly produced by small-scale manufacturers and amateur radio communities in the United States and other countries, as it is not mass-produced by a large company. The Hermes Lite 2 project is open-source, and hardware schematics are publicly available for anyone interested in building or assembling the device.
Independent producers and small distributors offer kits or fully assembled transceivers, usually built in home workshops or in collaboration with PCB manufacturers.
This approach helps keep Hermes Lite 2 an affordable and customizable device, though availability may vary depending on demand and each local producer’s capacity.
Summary
Hermes Lite 2 is a compact and affordable SDR transceiver created for amateur radio use, inspired by the original Hermes model developed through the OpenHPSDR project. It was designed by Steve Haynal (KF7O) and a small team of engineers and radio enthusiasts who aimed to create a simplified and accessible version for the ham radio community.
The initial project, Hermes Lite 1, launched in 2016, was successful and led to the improved Hermes Lite 2 version, which features better performance and open-source software compatibility.
One of the key software options is Thetis, an advanced program developed by Apache Labs and the OpenHPSDR community, as a continuation of PowerSDR. Thetis provides a modern interface, enhanced DSP capabilities, and extensive compatibility with Hermes Lite 2 and other modern SDR platforms.
Hermes Lite 2 remains a flexible and educational SDR platform, widely appreciated by amateurs worldwide.
Hadrian Portase Feldmann – YO2BTW