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Sherwood Engineering Inc. (SEI) offers a repository of technical presentations and white papers focused on optimizing amateur radio transceiver and receiver performance. Content includes detailed analyses of _roofing filters_, transmitted IMD, and receiver characteristics, with specific discussions on products like the Drake R-4C and Icom IC-781. Presentations from events such as Dayton Contest University (2008-2014) cover topics like "How To Optimize Rig Performance," "Transceiver Performance: 10 Years of Change," and "Choosing a Transceiver: Far from Simple." Additional white papers address HF mobile antenna efficiency, ground screen alternatives to buried radial systems, and common receiver problems with solutions. The site also provides historical product information for items like the SE-3 MK IV synchronous AM detector and various 455 kHz mechanical and crystal filters, though many products are no longer in production. Receiver test data and alignment tips for the R-4C are also available, offering insights into rig modifications and performance enhancements.

Over 45 years of dedicated work by Robert Sherwood, NC0B, culminated in a wealth of technical insights, particularly concerning **receiver performance** and the intricacies of transceiver design. The site provides access to numerous presentations from events like Dayton Contest University and W4DXCC, covering topics such as optimizing rig performance, the evolution of lab testing, and the impact of roofing filters on transmitted IMD and receiver characteristics. These resources offer detailed analyses and practical advice for serious operators and contesters. While product manufacturing, including the SE-3 MK IV synchronous detector and various Drake R-4C accessories like roofing filters and cooling kits, has ceased, the legacy of technical documentation remains. The site details specific products like the Icom IC-781 and R-9000, and offers insights into 455 kHz mechanical and crystal filters, along with DSP protection strategies. Crucially, the site features extensive receiver test data, allowing radio amateurs to compare the performance of various transceivers. This data, often presented in white papers and slide shows, includes detailed measurements and explanations of key performance metrics, serving as a valuable reference for understanding and selecting high-performance HF gear.

Receiver performance test of the Icom IC-7610 transceiver done by Rob Sherwood

Receiver performance review of the Kenwood TS-890S HF,50MHz,70MHz amateur radio transceiver by Sherwood Engineering

Jose B Rivera, N2LRB, shares his initial experiences with the Icom IC-7300, recounting a shift from skepticism to appreciation for the transceiver. He details how the radio's impressive Sherwood Engineering test results, ranking it #12, significantly influenced his decision, especially considering its competitive price point against higher-end options like the Elecraft K3s. The review highlights the IC-7300's strong receive capabilities, a key factor in N2LRB's purchasing decision, and notes the advantages of its SDR architecture for future updates. He describes the straightforward setup process, from unboxing and connecting PowerPole connectors to making a first contact with N0HQ, a special event station. N2LRB expresses satisfaction with the radio's clear audio and ease of tuning, even if the pan-adapter's utility for his operating style remains to be fully explored. He concludes that the IC-7300 offers exceptional value, providing SDR features and receive performance comparable to more expensive rigs at half the cost.

Filters and replacement parts for the Drake R-4C receiver by Sherwood Engineering Inc

A growing set of pages with tools and analyses of various elements of data elements based on Sherwood RX tests

Collection of test reports done by Rob Sherwood on the Elecraft K4D, this version of the K4 does not have the hybrid front-end.

Presents an extended-period review of the Yaesu FTDX10 HF transceiver, focusing on its operational usability and long-term reliability after approximately ten months of alternating use. The analysis details aspects such as the radio's interface logic, menu navigation, and overall functional consistency, contrasting these with published specifications and common user expectations. It addresses specific operational scenarios and evaluates the radio's behavior under various conditions, providing observations on potential discrepancies between advertised features and practical application, including issues like panel timing, knob placement, and DNR aggressiveness. The review compares the FTDX10's performance and user experience against the Icom IC-7610 and Icom IC-7300 transceivers, particularly regarding receiver performance, roofing filters, APF, and dedicated width/shift controls. It highlights disadvantages such as disabled functions during transmit, slow internal ATU performance, lack of spectrum scope averaging, and various quality assurance issues like volume knob faults, failing screens, and FT8 harmonics. The document also includes commentary on Yaesu's product support, noting a lack of response to user feedback, and observed reliability of the FTDX10 unit over time, offering a perspective beyond initial laboratory measurements like those from Sherwood Engineering.

The page presents a collection of blog posts tagged with "yaesu-ftdx10" from the VE3IPS WordPress site. It serves as an index for content related to the Yaesu FTdx10 transceiver, often in comparison with other popular HF rigs like the Icom IC-7300 and Yaesu FT-710 AESS. The aggregated content details specifications such as 100W output power and various SDR architectures. Specific articles linked from this tag page likely delve into operational aspects, including receiver performance, audio clarity, and user interface characteristics of these transceivers. Mentions of features like the IC-7300's real-time spectrum scope and USB integration, or the FTdx10's roofing filters and contest-proven Contour and DNR filters, indicate a focus on technical distinctions. The resource also highlights limitations, such as the basic 3:1 internal tuner in some models and the absence of VHF/UHF coverage in the IC-7300. The Yaesu FTdx10's superheterodyne and SDR approach, along with its placement on the Sherwood Engineering receiver performance list, are key points of discussion within the linked posts.

The Yaesu FTDX-10 transceiver features a hybrid receiver design, integrating a dual superheterodyne front end with an SDR chip for advanced DSP. This architecture aims to mitigate front-end overload, a critical consideration for HF operations. Performance data indicates a Reciprocal Mixing Dynamic Range (RMDR) that places the FTDX-10 at number two on Sherwood Engineering's ranking, highlighting its strong signal handling capabilities. The unit includes a 5-inch TFT touch screen and an internal antenna tuner effective up to 3:1 SWR, covering receiver frequencies from 30 kHz to 75 MHz. Operational aspects include a spectrum scope with 2D and 3DSS display modes, offering adjustable frequency spans from 1 kHz to 1000 kHz and five waterfall speeds. The review evaluates the efficacy of the noise blanker and Digital Noise Reduction (DNR) functions, essential for mitigating interference in various operating environments. Connectivity is supported via USB drivers for N1MM and HRD software, alongside DVI output for external display mirroring. The Multi-Purpose VFO Outer Dial (MPVD) enhances user interaction. The FTDX-10's design and features cater to serious amateur radio operators seeking high performance in a compact HF/50 MHz platform.

The Yaesu FTdx10 HF transceiver underwent comprehensive laboratory testing by Sherwood Engineering, with results documented on December 29, 2020. Key receiver performance metrics include IF bandwidth measurements at -6 dB and -60 dB for 2400 Hz and 500 Hz filters, showing ultimate rejection exceeding 100 dB and 105 dB respectively. Front-end selectivity and first IF rejection at 9005 kHz were measured at 91 dB. Receiver dynamic range, both with and without preamps, was consistently 107 dB at 20 kHz, 10 kHz, 5 kHz, and 2 kHz spacings without preamplification, and 106 dB with Preamp 1 at 20 kHz. Blocking performance reached 141 dB at 100 kHz offset with a 1uV signal. Phase noise was normalized across offsets from 2.5 kHz to 500 kHz, with a value of -145 dBc/Hz at 2.5 kHz and -155 dBc/Hz at 500 kHz. Reciprocal Mixing Dynamic Range (RMDR) peaked at 128 dB at 500 kHz spacing. Noise floor measurements for SSB and 500 Hz bandwidths at 14 MHz and 50.125 MHz showed -133 dBm with Preamp 2 at 14 MHz SSB. Sensitivity figures and S-meter accuracy were also documented, with one S unit equating to 3 dB from S3 to S9. Transmitter composite noise was measured at 100 watts and 30 watts, with values like -123 dBc/Hz at 2 kHz offset for 100 watts. Operational observations from the January 2021 CQWW 160m CW contest highlighted ergonomic issues, such as VFO knob placement and small buttons. A significant firmware limitation noted was the band scope and waterfall data being erased upon transmission, which severely reduces its utility for search and pounce operations.