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Microwave Filter Company is a leader in the design, development and manufacture of high quality passive electronic filter products in the 5 Hz to 50 GHz frequency spectrum.

SkyRoof is an open-source, 64-bit Windows application designed for amateur radio operators and satellite enthusiasts, combining satellite tracking and Software Defined Radio (SDR) functionality in a unified platform. The software provides real-time satellite tracking, pass predictions, and visual representations through Sky View, Earth View, and Timeline displays. It features an SDR-based waterfall display covering VHF/UHF satellite segments with Doppler-corrected frequency scales, automatic satellite labeling, and visual tuning capabilities. SkyRoof supports various SDR devices (Airspy Mini, SDRplay, RTL-SDR), external transceiver CAT control, and antenna rotator integration. The application automatically downloads satellite data from SatNOGS and other sources, offers voice announcements for satellite passes, and includes comprehensive frequency control with Doppler tracking, manual corrections, and RIT functionality for enhanced satellite communication operations.

Showcasing German engineering, ANjo Antennen develops and manufactures a diverse portfolio of amateur radio and commercial antenna products. Their offerings span a wide frequency range from 1.8 MHz to 3000 MHz, emphasizing electrical and mechanical precision for longevity. The company actively participates in events like FUNK.TAG Kassel, providing opportunities for direct engagement and order pickup. ANjo's product line includes high-performance **Yagi antennas** optimized for Tropo and EME, along with multi-stacked Quad antennas designed for contest operations, featuring wide horizontal and narrow vertical beamwidths. They also produce circularly polarized satellite antennas, some with switchable LHCP/RHCP, leveraging their commercial satellite antenna expertise. Beyond amateur applications, ANjo provides flexible, custom antenna solutions for commercial sectors such as BOS, EMC measurements, and telemetry. Their commitment to quality is evident in the Premium-Line antennas, which utilize **1.4301 (V2A) stainless steel** for mast clamps and connectors, ensuring durability and corrosion resistance. They also offer end-fed HF multiband wire antennas, known for their compact footprint and discreet installation.

TFilter is a free online tool for designing linear phase, optimal, equiripple finite impulse response (FIR) digital filters. It utilizes the Parks-McClellan algorithm implemented in JavaScript. Users can specify the sampling frequency, desired number of taps, passbands, and stopbands to generate a filter. An example configuration is provided for easy testing.

This project introduces the Loggi, a hybrid antenna merging the wide frequency coverage of log-periodic dipole arrays (LPDA) with the high gain and front-to-back ratio (F/B) of Yagi antennas. Traditional LPDAs span broad frequencies with moderate gain and low VSWR, while Yagis provide high gain and F/B over narrow bands. By analyzing high-Tau LPDA designs, it was found they could nearly match the gain of VHF/UHF Yagis while maintaining excellent patterns, F/B, and front-to-rear ratios (F/R). Optimizing specific elements for target frequencies (e.g., 144.1 MHz) led to the Loggi, which uniquely features all driven elements without passive directors or reflectors. This design effectively functions as a narrowband optimized LPDA, with front elements acting like Yagi directors and rear elements like Yagi reflectors, thus enhancing gain and directional characteristics while retaining broad frequency versatility.

This project delves into the development of a compact WSPR beacon, building on earlier experiences with weak-signal modes. Inspired by QRP Labs kits and modified open source designs, it integrates a Si5351 frequency generator, GPS module, and class E PA for efficient operation. Extensive optimizations—addressing drift, heat management, and power stability culminated in a portable, serviceable device. The beacon offers insights into propagation while minimizing reliance on main station equipment. Lessons learned highlight the importance of careful component selection and iterative design improvements for robust amateur radio experimentation.

The Dipole Bazooka Antenna for 40 meters is a popular choice among amateur radio operators. Its design allows for easy construction using materials like RG58 coaxial cable and PVC. Measurements are calculated using specific formulas; for instance, at a frequency of 7,100 MHz, the total length is approximately 19.74 meters. This antenna offers a performance range of 97% to 99%, with an impedance of 49 to 52 ohms. Additionally, it can handle up to 1 kW of power and requires no modifications for connection.

This article explores the nuanced design challenges of Band Pass Filters (BPF) in radio receivers, balancing low insertion loss, high stop band rejection, and narrow bandwidth. The focus is on the "Series-Trap, Shunt-C" topology, resonator count impact, and meticulous layout design for superior stop band performance across various frequency bands

This project describes the construction of a W3HH (T2FD) antenna for HF bands (3-30 MHz). While less efficient than a tuned dipole, it offers broad frequency coverage with a maximum SWR of 3.4 and reduces QRM (noise) significantly. On the 80-meter band, it shows slightly weaker signals than a dipole but with improved signal-to-noise ratio. The design includes non-inductive resistors, a 13:1 balun, and a "frog ladder" transmission line. Though not a high-performance antenna, it is compact and versatile, making it ideal for wide-band HF communication. Article in French

Learn how to design a Hentenna antenna, a portable asymmetrical double-loop antenna ideal for amateur HF or VHF bands. This page provides details on constructing and optimizing the antenna for maximum performance in DX communications. Discover how altering the antenna's vertical feed section can adjust the VSWR resonant frequency and how changing the support pole's position can alter the beam direction. Originally developed by Japanese 6-meter operators, the 'Hentenna' offers a unique design that allows for horizontal polarization when vertically oriented. Explore radiation patterns, VSWR charts, and antenna currents diagrams to optimize your antenna's performance for long-distance contacts.

Morsle.fun is a user-friendly web application designed for practicing Morse code reception by guessing transmitted text, which can be either words or call signs. Users can adjust the volume and tone frequency of the Morse code playback. The application tracks performance and generates activity statistics. Call signs are typically more complex than words, containing up to six characters and at least one digit. Users can practice Morse code at speeds ranging from 10 to 60 wpm.

OM0ET manufacture high capacity variable air capacitor and tuning unit designed for Magloop antennas. OM0ET explains features and benefits of this antenna, such as easy assembly, wide frequency range, and improved efficiency. Ideal antenna setup for indoor or outdoor use, offering better QSO performance and radio listening experience. The author, identified as OM0ET, shares insights on the design and functionality of the equipment, making it a valuable antenna for portable operations.

This article describes an HF upconverter for the FunCube Dongle Pro. Designed for radio amateurs, the converter extends reception capabilities to lower frequencies (0 Hz to 30 MHz) by mixing them with a higher oscillator frequency (100 MHz). This translates the desired signal into a range detectable by the FunCube Dongle (64 to 1,700 MHz). Key components include a double-balanced mixer and a low-pass filter to suppress unwanted signals. The project provides schematics, filter specifications, and design considerations for construction.

An **Arduino LC Meter** provides an accessible solution for precisely measuring inductance and capacitance values, crucial for RF circuit design, filter tuning, and troubleshooting in amateur radio applications. This project details the construction of a low-cost, accurate instrument using readily available components, making it an attractive alternative to commercial units for hams and electronics enthusiasts. The build process involves assembling a resonant circuit, integrating an Arduino microcontroller for frequency measurement, and displaying results on an LCD. Key components include an Arduino Uno, a 16x2 LCD, a 74HC14 Schmitt trigger inverter, and a few passive components. The design leverages the Arduino's processing power to calculate L and C values from resonant frequency shifts. Calibration procedures are outlined to ensure measurement accuracy, which is vital for critical RF work. The project includes schematics, a parts list, and the necessary Arduino code, enabling hams to construct a functional LC meter for their workbench.

Effective suppression of harmonics and parasitic radiation from HF transmitters is crucial, especially with the increasing sensitivity of VHF/UHF radio channels to interference. This project details a hybrid low-pass filter (LPF) designed to operate across the HF bands up to 51 MHz, making it suitable for 6-meter band operations while providing deep VHF/UHF suppression. The design addresses the challenge of modern interference landscapes, where even microvolt-level signals can disrupt wireless sensors and other simple VHF/UHF receivers. The filter utilizes a single elliptic link, combining high cutoff steepness with robust suppression in the hundreds of megahertz range. A key feature is the use of only two standard capacitor values, simplifying construction and component sourcing. The article provides a detailed schematic, performance characteristics, and _RFSim99_ model file, demonstrating a reflection coefficient S11 below 0.017 (VSWR < 1.03) across 1-51 MHz, ensuring minimal degradation to the antenna system. Construction notes include coil winding specifications and capacitor selection guidance, with recommendations for _FR-4_ assembly. Two capacitor sets are presented, with the first variant recommended for its lower RF current demands, keeping currents below 3 A at 1 kW passing power at 51 MHz. Fine-tuning involves adjusting frameless coils, with considerations for capacitor tolerance and high-frequency capacitance measurement accuracy.

The UV-K5 HF Fullband receive firmware version 0.3 introduces enhanced SSB capabilities using the SI4732-A10 chip. Released separately from UV-K5 CEC firmware, it offers improved HF reception, mode changes, frequency fine-tuning, and user modifications. New PCB designs and detailed usage instructions are included.

Learn how to build a VHF 144MHz transverter connected to an LMR SDR radio using easily accessible components. The transverter works by mixing the 144Mhz input frequency with a 116 MHz local oscillator frequency. Explore the challenges of finding a 116 MHz crystal and the solution of using a programmable Si5351A oscillator. Follow the provided schematic for the RX and TX sections. The transverter design is still a work in progress, with ongoing trials to achieve optimal results.

When new to the 2-meter FM transceiver, securing a quiet frequency for chatter seems straightforward, but it's essential to navigate FCC rules and band plans effectively. Even though frequency allocations are consistent above 50 MHz for Technician licenses, adherence to specific segments within the 2m band—ranging from 144 MHz to 148 MHz—is crucial. This includes respecting designations for different modes like CW, SSB, and FM to prevent interference, particularly with satellites and exotic modes like EME. Understanding and following the structured band plans not only ensures legal compliance but also optimizes frequency use and minimizes disruptions in the amateur radio community.

When installing a mobile antenna, optimal placement significantly impacts performance. Factors such as gain, antenna type, ground plane availability, mounting style, and environment must be considered. Antenna designs, such as 1/4 wave and 5/8 wave, have distinct radiation patterns ideal for specific settings—urban areas or flat terrains, respectively. Ground plane size requirements differ by frequency, impacting effectiveness. Among vehicle mounting options, the car roof center provides the best ground plane and minimal obstruction, ensuring peak performance, especially at higher frequencies like 800 MHz.

The FT101ZD DDS VFO project replaces the original VFO in the Yaesu FT101Z/ZD rigs with an AD9850 DDS module, providing enhanced frequency control. It uses the original optical encoder and clarifier for compatibility, with a custom 6V power supply modification. The project includes selectable step sizes, a frequency save function, and works with both RX and TX modes. The design involves mechanical and electronic modifications, including SMD components and a custom PIC processor. Calibration ensures accurate frequency output, with further improvements under consideration.

This PDF document contains construction notes for a Yagi antenna designed for the 146 Mhz frequency range. It provides detailed instructions and information on how to build the antenna, making it a valuable resource for hams looking to improve their radio setup. The document covers the materials needed, step-by-step construction process, and tips for optimizing performance. Whether you are a beginner or an experienced ham radio operator, these construction notes can help you enhance your antenna system for better communication.

This article explores the powerful features of AutoEZ as an Excel application working with EZNEC antenna modeling software. The article demonstrates how variables, equations, and formulas enable versatile antenna design and automatic optimization. Through practical examples including dipoles, inverted vees, delta loops, and monopoles, the author shows techniques for achieving resonance, implementing transmission line resonators for broadbanding, and optimizing antennas across frequency ranges. The step-by-step demonstrations cover unit conversion, coordinate calculations, segmentation considerations, and SWR optimization. This practical guide illustrates how AutoEZ extends EZNEC's capabilities, making complex antenna modeling more efficient and accessible.

KISS703 is a 703 Hz narrowband digital mode for amateur radio, designed for simple, low-power operation without computers. A 500 Hz pilot tone ensures frequency alignment, replaced by unique tones for 37 symbols (letters, numbers, space). Built from common discrete components, it draws about 40 mA at 12 V, ideal for SOTA/IOTA use. The receiver uses amplification, wave shaping, and a pulse-counting frequency meter for manual decoding via a calibrated meter. Transmitter and receiver calibration involves marking meter positions for each tone, enabling fully self-contained messaging with minimal hardware in portable or fixed operations.

Improve the FRG-7 operation adding a home made digital frequency display. The author explains the challenges of using the analogue dial on the FRG-7 and how a digital display can be a useful solution. The page provides detailed information about the FRG-7's design and frequency conversion process. It also includes step-by-step instructions on how to connect an external frequency counter to display the kHz part of the frequency.

YAGio 1.01 is a Windows-based software for designing DL6WU long Yagi antennas on VHF and UHF frequencies. It supports Windows 2000, XP, Vista, 7, and likely 8. Using keyboard commands, users input specifications such as frequency, gain, and element diameters, and YAGio generates the design. You can download latest Yagio version from this page. Results can be saved in YIO, NEC, YAG, MMA, and YC6 formats, or printed directly.

This resource details the construction and performance of a compact broadband magnetic loop antenna designed for portable receiving applications with devices like the _ATS MiniRadio_. The antenna utilizes approximately 3 meters of 0.5–1 mm copper wire wound in two turns on a rhomboidal wooden frame, measuring 50 cm by 70 cm. It connects via a modified 9:1 unun, where the primary center tap is isolated from ground to improve common-mode noise rejection. The design provides untuned operation across a frequency range from the longwave band up to approximately 25 MHz. Performance characteristics include observable directivity for noise suppression and the ability to connect directly to a radio or via a 50 coaxial cable for remote operation. The article specifies the unun's 3:1 turns ratio and its SMA output for connectivity. The methodology focuses on practical construction and observed reception quality.

A dual insert microphone design for the Icom IC-7300 transceiver utilizes a **Besson BZ2400 M4 Rocking Armature** insert for frequencies from 500 Hz to 3 kHz, exhibiting a rising response of approximately 11 dB. A generic Electret Condenser insert, powered by the transceiver's microphone line, covers the low-frequency range from 100 Hz to 500 Hz. A Low Pass Filter is incorporated after the Electret insert to prevent frequency overlap, and a pre-set potentiometer (VR1) adjusts the low-frequency response, balancing the output of both inserts. The design emphasizes a "Close Talking" arrangement and addresses audio "colorization" by housing the Besson insert in a thick rubber holder with a foam boot, separate from the circuitry, with the Electret insert also wrapped in a foam boot. Critical importance is placed on using the correct BZ2400 M4 insert with 12 holes in its face plate. The frequency response table for the BZ2400 M4 insert shows 0 dB at 500 Hz, rising to +11 dB at 3000 Hz, while the Electret insert with the Low Pass Filter provides 0 dB at 100 Hz, rolling off to -9 dB at 500 Hz and -50 dB at 3000 Hz. This combination ensures a broad, balanced audio spectrum for SSB operation. The project includes a circuit diagram, a comprehensive parts list detailing components like a 1 Henry iron-cored inductor (L1) and various capacitors, and a board layout within the metal tube. The completed unit provides a tailored audio profile for the IC-7300, enhancing transmit audio quality.

DXLog.net Cluster functions as a dedicated client application designed to enhance DXLog.net contest logging operations. It facilitates simultaneous connections to multiple DX cluster nodes, providing a consolidated view of DX spots. The software also supports integration with local CW skimmers, enabling real-time reception of CW signals and their automatic decoding into spots. The utility broadcasts UDP data across the local area network, allowing DXLog.net to receive and process these spots efficiently. A key feature includes CAT control integration, which automatically QSYs connected CW skimmers to the frequency of interest, optimizing spot acquisition. The system also incorporates duplicate spot filtering to reduce redundancy and offers blacklist management for unwanted callsigns or frequencies. Programmable commands and dynamic skimmer bandwidth control further refine its operation, adapting to varying band conditions and contest strategies. Automatic reconnection capabilities ensure continuous operation, maintaining reliable access to DX information crucial for competitive contesting.

145 MHz is the target frequency for this 2-meter Skeleton Slot Yagi Stack antenna project. The design focuses on feeding two stacked Yagi antennas using a skeleton slot radiator, which is a unique approach for VHF enthusiasts. The project details the construction process, including the loop tapered matching section for impedance matching, ensuring optimal performance. The use of specific components like the EH789 element holder and MB456 main mast bracket is highlighted, providing clarity on the assembly process. The construction utilizes 20x20 box aluminum bar for durability and precision. Key dimensions, such as the element length (ER-ED4) and main boom spacing (MM123), are meticulously outlined. This attention to detail aids in replicating the antenna design accurately. The downloadable PDF offers comprehensive instructions, making it accessible for amateur radio operators interested in VHF antenna construction. This project is particularly beneficial for those looking to optimize their 2-meter band operations. The inclusion of a skeleton slot radiator and loop tapered matching section demonstrates advanced techniques in antenna design, catering to both intermediate and advanced builders.

The Icom IC-9700 transceiver, a popular choice for VHF/UHF/1.2 GHz operations, gains enhanced remote control capabilities through Pycom Radio Controller. This software provides direct _CI-V based control_, enabling operators to manage frequency, mode, memories, and tones from a connected computer. It integrates a built-in rigctl server and supports popular satellite tools like Gpredict and SatPC32, facilitating full duplex Doppler control for satellite passes. Key features include real-time meters, a waterfall display, and remote RC-28 integration. Designed for practical amateur radio use, the application streamlines voice and digital satellite operations. It allows for full duplex remote Doppler control, crucial for maintaining accurate frequencies during satellite contacts. The software also incorporates callsign lookup and logging functions, alongside enhanced memory management. Documentation pages offer configuration guidance and operating examples, ensuring users can effectively set up and utilize the software for their satellite communication needs, potentially improving success rates for contacts and contests.

The article discusses the construction of a UHF band-stop stub filter to protect an APRS receiver from potential damage during a balloon launch. The author, who communicates using a 441 MHz transmitter, needed to ensure that the RTL-SDR dongle receiving at 144 MHz wouldn't be damaged by the transmissions. The solution involved creating a quarter-wavelength open stub filter using coaxial cable, which attenuates the 441 MHz signal while allowing the 144 MHz signal to pass through. The filter's design is based on the principles of constructive and destructive interference, with careful measurement and trimming to achieve the desired frequency response. The final filter provided 34.8 dB of insertion loss at 441 MHz and minimal loss at 144 MHz, effectively protecting the receiver.

The Olivia digital mode, a **Multi-Frequency Shift Keying (MFSK)** radioteletype protocol, is specifically engineered for robust communication under difficult propagation conditions on shortwave radio bands from 3 MHz to 30 MHz. Developed by Pawel Jalocha in 2003, Olivia signals can be decoded even when the noise amplitude exceeds the digital signal by over ten times, making it highly effective for transmitting ASCII characters across noisy channels with significant fading and propagation phasing. Early on-the-air tests by Fred OH/DK4ZC and Les VK2DSG on the Europe-Australia 20-meter path demonstrated intercontinental contacts with as little as one-watt RF power under favorable conditions. Common Olivia modes are designated as X/Y, where X represents the number of tones and Y is the bandwidth in Hertz, with examples including 8/250, 16/500, and 32/1000. The resource clarifies that Olivia, unlike some other digital modes, produces a constant envelope, allowing RF power amplifiers to achieve greater conversion efficiencies and making it less prone to non-linearity. Operators are advised that **Automatic Level Control (ALC)** can be set higher than no meter movement for MFSK modulation, as long as it's not driven past its high limit, contrary to common misinformation about other digital modes. The Olivia community encourages voluntary channelization on suggested calling frequencies, such as 14.0725 MHz for 8/250, to facilitate initial contacts, especially for signals below the noise floor. The Olivia Digital DXers Club provides links to Groups.io, Facebook, and Discord for community engagement and offers details on QSO parties.

Twenty 1-watt carbon film resistors are configured in parallel to construct a 50-ohm **dummy load** for amateur radio applications. The design incorporates a heatsink for thermal dissipation and an **SO-239 connector** for RF input, making it suitable for QRP operations. This budget-friendly project details component selection, soldering techniques, and mounting procedures, achieving a continuous power rating of 10 watts and intermittent handling of up to 100 watts across HF and VHF frequency ranges. The resource provides a step-by-step guide for assembly. This construction offers an economical solution for essential shack tasks such as antenna tuning, transmitter testing, and SWR meter calibration without radiating an RF signal. The utilization of readily available components significantly reduces the overall build cost compared to commercial alternatives, providing radio amateurs with a functional and reliable test accessory. While specific VSWR measurements are not provided, the design prioritizes practical utility for low-power transceiver diagnostics and general RF experimentation.

The project details the construction of a GM3OXX OXO transmitter, designed to accommodate **FT-243 crystals** using 3D-printed FX-243 holders from John KC9ON. It presents specific frequency adjustments, noting a 7030 KHz HC-49/s crystal could be tuned from 7029.8 KHz to 7031.7 KHz with an internal 45pF trimmer capacitor. The build incorporates a modified keying circuit to prevent oscillator run-on key-up and includes a TX/RX switch for sidetone via a connected receiver, with the transmitter output routed to a dummy load on receive. Practical construction aspects are thoroughly covered, including the process of cutting a rectangular opening in a diecast enclosure for the FT-243 socket and the selection of a **low-pass filter** (LPF) based on the QRP Labs kit, derived from the W3NQN design. The author achieved approximately 800mW output power from a 14.75V supply, measured with an NM0S QRPoMeter, using a 16.5-ohm emitter resistor in the 2N3866 final stage. The article also touches upon the potential for frequency agility across the 40M band using multiple FX-243 units with various crystals. The narrative includes a brief diversion into Bob W3BBO's recent homebrew projects, such as his Ugly Weekender MK II transceiver, highlighting the enduring appeal of classic QRP designs. The author reflects on the personal satisfaction derived from building RF-generating equipment, irrespective of DX achievements, and shares experiences of making local contacts with the 800mW OXO transmitter on 40 meters.

The article details how to eliminate Radio Frequency Interference (RFI) from the Behringer HA400 headphone amplifier when used in ham radio setups. While the HA400 is praised for its quality and affordability, it was not designed for RF environments, causing distortion when used with a 500-watt radio station. Initial attempts using clamp-on ferrites on the headphone and power cables only partially resolved the issue. Upon opening the unit, the author discovered the circuit lacked RF bypassing components. The solution involved installing 0.1μF (104) capacitors at key points in the circuit: the power supply input, audio circuits, and op amp inputs. This modification, combined with the external ferrites, completely eliminated the RFI problem, making the unit suitable for ham radio operations.

This page provides an introduction to the ZL2PD LED Frequency Counter. It covers the design, construction notes, and downloads related to the project. Created by Andrew Woodfield, ZL2PD, this resource offers valuable information for hams interested in building their own frequency counter using LEDs. The content is dated June 12, 2010, with a revised version 2.0. The page also credits the template design by Andreas Viklund.

The **Yaesu FRG-100** shortwave receiver, introduced in 1992, operates across a frequency range of 50 kHz to 30 MHz, accommodating AM, LSB, USB, and CW modes, with an optional narrow-band FM capability. Its physical dimensions are 238 x 93 x 243 mm, with a weight of 3 kg, making it suitable for both portable and fixed station deployments. Power options include standard mains voltage or 12VDC, providing operational flexibility for diverse listening environments. The front panel integrates a manual tuning knob, an analogue signal strength meter, and an LCD display that provides critical information such as frequency, operating mode, memory channel, and time. Users can configure various operational parameters, including tuning steps and bandwidth filters, to optimize reception for specific signals. This review highlights the FRG-100's straightforward interface and its utility for shortwave listening enthusiasts. The design emphasizes user-friendly adjustments for settings, which contributes to its appeal among those interested in general coverage reception.

Demonstrates the construction of an active loop converter specifically designed for the Low Frequency (LF) bands, addressing common localized noise interference in LF reception. The design integrates a sharply tuned circuit and a tuned loop antenna, utilizing the loop as the sole tuned inductive element. By applying positive feedback, the converter significantly increases the loop's effective Q, achieving factors between 1000 and 2000, which sharpens tuning and reduces noise. The circuit employs an _NE602_ mixer stage, feeding its output to an HF receiver, with a crystal-locked local oscillator at 4 MHz. A 20-turn, 0.8-meter square loop antenna with 500 uH inductance is detailed, connected via 2 meters of figure 8 flex cable. The converter offers three selectable frequency bands: 195-490 kHz, 150-220 kHz (including the New Zealand amateur band), and 128-160 kHz (covering the European amateur band). Performance measurements indicate an effective 3dB bandwidth of approximately 100 to 200 hertz at 200 kHz. The article provides insights into component selection, including an _LF353_ op-amp and a trifilar wound transformer on a ferrite core. Sensitivity figures are presented, showing 7.5 uV of converted output per 1 uV/meter signal strength into a 50-ohm load, or 37.5 uV into an _FRG7_ receiver, highlighting its capability to extract weak signals from noise.

Demonstrates the construction of 'The Virgin', a **direct-conversion receiver** specifically designed for the 40m amateur radio band. This project, completed in February 2016, features a fixed operating frequency determined by a crystal oscillator, requiring a physical crystal change to alter the reception frequency. The design incorporates two integrated circuits and a power regulator, emphasizing simplicity with a single control knob. The author details the initial design, subsequent modifications to the front end, and troubleshooting steps addressing common issues like audio motorboating and power supply instability. The resource presents the final design of the receiver, reflecting the author's first experience building such a unit between December 2015 and February 2016. It offers practical insights into basic circuit construction and the iterative process of refining a homebrew radio project. The content is particularly relevant for those interested in fundamental receiver principles and hands-on **QRP** transceiver building.

Examines the AOR AR-7030 communications receiver, detailing its technical specifications and operational characteristics. The resource describes its compact design, CNC machined aluminum cabinet, and a frequency range spanning 0-32 MHz. Key features include a ceramic metal cased 4 kHz AM filter, with typical bandwidths of 2.2 kHz, 4.0 kHz, 5.3 kHz, and 9.5 kHz, alongside 400 memory channels and multi-timer functionality. It emphasizes the receiver's high-quality components and a design philosophy focused on reliable performance without superfluous features, making it a dedicated tool for serious listeners. The review assesses the AR-7030's performance within its price class, particularly for **medium wave** and **shortwave** reception. It provides insights into how the receiver's design choices, such as its robust construction and specific filter options, translate into practical listening experiences. The analysis highlights its suitability for users prioritizing signal clarity and operational stability over extensive, complex features, offering a clear perspective on its utility for dedicated DXers and broadcast listeners.

The W6PQL 23cm Beacon Project describes a **1296 MHz** beacon designed for microwave propagation studies and equipment testing, capable of 30 watts output. It utilizes a PIC 16F628A microcontroller to generate CW and FSK keying for a crystal oscillator, followed by a series of frequency doublers and triplers to reach the target frequency. The final power amplification stage employs a Mitsubishi M57762 module, providing a robust 10-watt RF output. The design emphasizes stability and reliability for continuous operation, with the microcontroller code, written in assembly, provided for customization of the beacon's callsign and message. Originally located in CM97am and aimed at 140 true, the beacon used four 4-foot Yagis stacked vertically for a total ERP of 3kW. The article includes schematics, parts lists, and construction notes to guide builders, along with antenna pattern measurements. Although the beacon itself is no longer in service as of August 2010, the detailed documentation remains a valuable reference for amateur radio operators interested in building similar **microwave** projects or understanding beacon operation.