Search results

This guide provides step-by-step instructions for constructing a tin can waveguide antenna, commonly known as a cantenna, for enhancing WiFi signal range. The project is budget-friendly, costing under $5, and utilizes easily accessible materials like a food can and basic electronic components. The design is suitable for 802.11b and 802.11g wireless networks, operating within the 2.4 GHz frequency range. To start, gather the necessary parts including an N-Female chassis mount connector, nuts, bolts, and a suitable can. The assembly process involves drilling holes in the can for the connector and mounting the probe. The guide emphasizes the importance of can dimensions and placement for optimal performance, encouraging experimentation for best results. This project is ideal for amateur radio operators and DIY enthusiasts looking to improve their wireless connectivity without significant investment. Safety precautions are advised, as the author does not hold electrical engineering credentials. Users are encouraged to take responsibility for their equipment and ensure proper assembly. With this simple yet effective antenna, users can extend their WiFi coverage and enjoy enhanced connectivity.

Constructing a 2.4 GHz high-gain _cantenna_ for wireless networks is detailed, providing a practical approach to extending WiFi range. The author, WB8ERJ, shares insights into building these devices, noting their application in amateur radio for projects like Hinternet or HSMM (High-Speed Multimedia) networks. The article outlines the necessary components and steps, emphasizing the DIY aspect for hams interested in digital modes and local area networking. The resource explains how to determine the correct probe placement within the can, a critical dimension for optimal performance at 2.4 GHz. It references specific measurements, such as the 1.25-inch distance from the can's bottom, derived from calculations for the 2.4 GHz band. This precision ensures the antenna functions effectively for its intended purpose of signal amplification. Readers gain actionable knowledge for fabricating a functional antenna from common materials, suitable for experimentation or practical deployment in a ham shack or field environment. The focus remains on the hands-on construction and the measurable results of improved signal strength.

Dissects the internal components of the popular _Antron 99_ vertical antenna, revealing its unique design elements. The analysis details the construction of the coaxial phasing sections, which contribute to its multi-band performance across 10, 12, 15, and 17 meters. Observations include the use of fiberglass tubing for weather protection and the specific arrangement of conductors within the antenna's structure. The examination highlights the antenna's reliance on a series of coaxial stubs to achieve resonance on multiple HF bands without external tuning. This internal architecture provides insights into how the _Antron 99_ manages impedance matching and radiation patterns for effective DX operation. Further details cover the antenna's base mounting and overall physical dimensions.

Amateur radio operators often seek reliable equipment for various modes and bands, from QRP operations to high-power DXing. Historically, Ten-Tec has been a notable manufacturer in the amateur radio market, known for its range of products including HF and VHF transceivers, RF amplifiers, and antenna analyzers. Their product line also encompassed specialized items such as QRP transceivers and kits, catering to enthusiasts of low-power communication, and antenna tuners for impedance matching. The company's offerings included test equipment vital for shack setup and maintenance, like SWR meters and RF analyzers, which assist in optimizing antenna systems and ensuring efficient power transfer. Additionally, Ten-Tec provided various accessories and components, supporting both commercial products and homebrew projects. The brand was recognized for its _made in the USA_ manufacturing, appealing to operators who prioritize domestic production. While the website currently displays limited product information, it mentions upcoming items like the _MODEL 594 PHOENIX_ and the _Tune-A-Tenna_, indicating potential future product releases.

The project details a DIY SWR/Wattmeter designed around an _Arduino Uno_ shield, providing capabilities to measure RF power from 2 to **200 watts** and Standing Wave Ratio (SWR) for HF amateur radio bands. This construction features a compact design, integrating the measurement circuitry directly onto a custom PCB that interfaces with the Arduino Uno microcontroller. Key components include a directional coupler for sensing forward and reflected power, precision rectifiers, and analog-to-digital conversion for processing RF signals. The Arduino firmware handles calibration, calculations, and displays the results on an integrated LCD, offering real-time feedback on antenna system performance. The design prioritizes simplicity for homebrewers. Performance specifications indicate accurate readings within the **2-200W** power range, suitable for typical QRP to medium-power HF operations. The project provides schematics and a basic overview of the software logic.

Demonstrates the construction of a **remote antenna tuner** utilizing a standard radio-controlled (RC) servo mechanism to adjust a variable capacitor. The design focuses on enabling remote tuning for narrow-bandwidth antennas, specifically mentioning frame and packing crate antennas, from within the shack. It covers the mechanical arrangement for integrating the servo with a capacitor and provides a circuit diagram for a control unit that generates the necessary 0.5mS to 1.5mS pulse-width modulation (PWM) signals to drive the servo's 180-degree rotation. This setup was successfully tested with up to 20 watts RF power without arcing or adverse effects on the servo, though tuning was performed at 1 watt for VSWR readings. The resource highlights the use of inexpensive, readily available components, such as Futaba servos, and details critical considerations like power supply decoupling with a 47uF capacitor to prevent unintended servo movement upon power-off. The system provides a practical solution for optimizing antenna performance for specific frequencies without manual adjustment at the antenna itself.

An inexpensive external GPS antenna, for 1.5 GHz band for GPS receiver, If you operate APRS or just need an external antenna for your GPS receiver, here's one that is easy to build yet offers surprisingly good performance in a compact size. Best of all, it uses commonly available components and materials.

The directory lists several files, including `_template1.html` and `_template2.html`, last modified in 2006 and 2004 respectively, indicating a historical web project. Key scripts like `hfcc_cfm.pl` and `index.cgi`, updated in 2011, suggest a **CGI-based application** for searching shortwave broadcast schedules. The presence of `_template1.tpl` and `_template2.tpl`, both modified in 2015, points to a templating system for dynamic content generation. The file `hfcc_create-fill_mys..>` (likely `hfcc_create-fill_mysql.pl`) implies interaction with a database, possibly MySQL, for storing and retrieving **HFCC (High Frequency Co-ordination Conference)** schedule data. The `lang.cgi` script, last updated in 2002, suggests early support for multilingual interfaces or language-specific content delivery. The `q.txt` file, a small 804-byte text file, could be a query log or a simple data file. The overall structure indicates a system designed to process and present shortwave broadcast information, likely by querying a database of scheduled transmissions on various HF frequencies. The file modification dates suggest the project was actively developed and maintained over a period spanning more than a decade, with core components last updated around 2011 and templates in 2015.

Catalogs a diverse array of Software Defined Radio (SDR) projects and realizations, systematically classified by their sampling methodologies and underlying hardware architectures. The resource delineates projects into categories such as those utilizing soundcard sampling of traditional transceiver audio outputs (Type Ia), mono soundcard sampling of intermediate frequencies (Type R1x-x-xx), stereo soundcard sampling of I/Q IFs (Type Q1x-x-xx), dedicated stereo audio ADC sampling of I/Q IFs (Type Q2x-x-xx), direct antenna RF signal sampling with off-the-shelf acquisition boards (Type R3x-x-xx), dedicated RF ADC sampling of analog IFs (Type R2x-x-xx), dedicated RF ADC sampling of direct antenna RF signals with ASIC-based processing (Type R4x-A-xx), FPGA-based processing (Type R4x-F-xx), and specialized IF chipsets combining ADC and DDC functions (Type Dxx-S-xx). Each entry provides a brief description, often including pricing, availability of source code, and specific hardware components like ADCs, DACs, DDS, and FPGAs. The compilation presents various practical applications, from PSK31 and Packet radio implementations to adaptations of the DRM standard for amateur radio bandwidths, such as Hamdream and WinDRM. It features specific hardware designs like the SoftRock-40 for the 40-meter band, the Firefly SDR for 30m and 40m, and more complex systems like the Quicksilver QS1R, which employs a 16-bit 130 Msamples/s ADC and an Altera Cyclone III FPGA. The resource also lists sample processing software, RF front-end designs, and academic/commercial SDR initiatives, offering insights into different approaches for I/Q conversion and digital signal processing in SDR systems.

Constructing a **2-meter** J-pole antenna from readily available copper plumbing components offers a robust and cost-effective solution for VHF operation. This design, dubbed the "Plumber's Delight," functions essentially as a half-wave dipole fed by 50-ohm coax via a **gamma match**. It incorporates a quarter-wave copper tubing support, which, when affixed to a metal mast or tower, enhances forward power in the direction of the radiating elements. The original configuration utilized a small ceramic trimmer capacitor for the gamma match, suitable for up to 10 watts. A subsequent modification replaced this with a 50 pF variable capacitor housed in a plastic enclosure, accommodating higher RF power and improving weather resistance. The antenna elements are secured using a copper "T" fitting, and an SO-239 connector mounts directly to this fitting. Performance includes gain away from the support mast, and tuning is straightforward by adjusting the gamma match capacitor for a 1:1 SWR. The total cost for materials, excluding the capacitor and coax, can be under $10.

Presents Telstar Electronics as a manufacturer specializing in amateur radio accessories, detailing its history since 1995 and highlighting key product offerings. The resource specifically mentions the _VoiceMax Transceiver Speech Processor_, designed to enhance audio fidelity and punch for SSB transmissions, and the _SkyWaveDX350_, indicating a focus on signal processing and reception improvement for DX operations. The company's product categories span ham radio accessories, microphones, and RF amplifiers, catering to various aspects of a station setup. The site implies a direct-to-consumer model for these specialized components, providing technical solutions for Icom, Yaesu, and Kenwood transceivers, and supporting homebrew enthusiasts with components and technical references.

The homemade CW paddle key design, inspired by a QRP homepage, utilizes soldered PC board material for its construction. The builder, DL5NEJ, modified an existing design to achieve a smaller footprint, preferring a compact setup for portable operations. This paddle was specifically built to complement a Wilderness Radio SST20 QRP transceiver kit, demonstrating its suitability for low-power operations. The project details suggest a straightforward assembly process, with the primary components being readily available PC board scraps. The design emphasizes simplicity and functionality, aiming to provide a reliable keying experience comparable to commercial paddles like the Bencher. Performance evaluations indicated the simple paddle operates effectively, prompting further exploration into similarly minimalist QRP rig designs. Additional construction details for a similar paddle are available from PA0CMU.

The Elecraft K3, a popular HF transceiver, is often benchmarked against new market entrants. This article critically compares the Kenwood TS-590S to the K3, focusing on key technical specifications and operational aspects relevant to serious amateur radio operators. The author proposes three distinct evaluation methods: a circuit diagram comparison, an independent review analysis (referencing Peter Hart, G3SJX, in RadCom), and a real-world "ear test" by experienced contest operators on 40 and 80 meters. The analysis delves into specific receiver components, including the first mixer design, RF and IF amplifier performance, and the presence of an image noise filter. It highlights the K3's switched mixer and the potential for the TS-590S to utilize similar or improved designs, such as a classic filter with enhanced selectivity. The article also scrutinizes the second mixer stage, noting the K3's SA612 chip and its associated IP3 limitations, suggesting Kenwood might achieve benefits with a different mixer architecture. Further points of comparison include DSP capabilities, where the K3's high-performing DSP with KK7P's involvement is noted against the TS-590S's potential reliance on newer IC technology but possibly less refined software. The discussion extends to DDS and PLL implementations for phase noise and spurious emissions, and the utility of a second receiver for DX chasing and contesting, acknowledging its importance for some operators while being less critical for others. The article concludes by emphasizing personal preference in equipment selection.

Over 75 years of engineering expertise underpins Bird Electronic's offerings in RF power measurement, critical for maintaining peak performance in amateur radio stations and professional communication systems. The company specializes in a range of test equipment, including wattmeters, SWR meters, and antenna analyzers, essential for optimizing antenna systems and ensuring efficient power transfer. Their product line extends to various RF components such as filters, cables, and connectors, all designed to meet stringent technical specifications for reliability and accuracy across diverse frequency bands. Bird Electronic's instruments, like the _Bird 43_ Thruline Wattmeter, are widely recognized for their robust construction and precise measurement capabilities, providing hams with confidence in their station's operational parameters. These tools enable accurate assessment of forward and reflected power, SWR, and modulation characteristics, which are vital for troubleshooting and maximizing radiated power. The company's commitment to innovation ensures that its products remain relevant for modern RF challenges, from HF through microwave applications, supporting both traditional analog and advanced digital modes.

PA3FWM's software defined radio (SDR) page documents his extensive hardware and software development efforts between 2004 and 2009. Initial experiments utilized a direct conversion receiver with 90-degree phase difference, feeding a PC soundcard at 48 kHz sample rate, covering 24 kHz of spectrum around a 7080.5 kHz local oscillator. This setup, similar to AC50G's QEX 2002 article, allowed for basic I/Q signal processing to distinguish signals above and below the LO frequency. Limitations included fixed crystal frequencies, 16-bit dynamic range, and narrow bandwidth. Subsequent hardware iterations aimed for enhanced performance, incorporating external 24-bit ADCs with 192 kHz sample rates, connected via 10 Mbit/s Ethernet. A **MC145170-based PLL** and programmable octave divider provided a 58 kHz to 30 MHz tuning range. The **Tayloe mixer** was employed, with differential outputs feeding a PCM1804 ADC. An ATmega32 microcontroller handled serial data conversion to Ethernet frames, though without CRC calculation due to processing constraints. Later designs integrated AD7760 2.5 Msamples/second ADCs and a Xilinx Spartan-3 FPGA, enabling direct reception of 0-1 MHz spectrum and eventually 2.5 MHz bandwidth across the shortwave spectrum. Software was refactored to use an initial 8192 non-windowed FFT for efficient high-bandwidth processing. The project culminated in a two-way QSO on 21 MHz using the developed hardware and software, demonstrating transmit capabilities with a D/A converter. The system exhibited a 2.5 MHz wide spectrum display and a zoomed 19 kHz display, capturing signals like ionospheric chirp sounders and RTTY contest activity. Challenges included noise leakage from digital circuitry and cooling for high-power dissipation components.

RSCW demonstrates a Linux/Unix command-line utility engineered for **Morse code** decoding via a computer's sound card. It specifically targets the extraction of weak CW signals from noise, operating on 8-bit, 8000 samples/second audio input, typically from `/dev/dsp`. The program outputs decoded characters to `stdout`, supporting user-specified speeds in words per minute (WPM) and carrier frequencies. While effective for machine-sent signals, it exhibits a 2-second decoding lag and requires manual speed input, making it less suitable for general-purpose, real-time contest operation. The resource details the program's components, including `rscw` (the main decoder), `rscwx` (an X11 graphical auxiliary for spectrum and internal signal visualization), `rs12tlmdec` (a specialized decoder for RS-12 amateur radio satellite telemetry), and `noisycw` (a utility for generating noisy Morse signals for testing). Installation instructions involve downloading a `.tgz` file, compiling with `Make`, and requiring the FFTW library (and GTK 2.0 for `rscwx`). Performance is illustrated with a .wav file example of a 12 WPM, 800 Hz CW signal at 12 dB Eb/N0, showcasing RSCW's near-error-free decoding of a test message. The site provides command-line examples utilizing `sox` for audio conversion and `noisycw` for signal generation, inviting comparisons with other decoding software and human operators, particularly for weak signal conditions.

The Buddipole website showcases a range of portable amateur radio antenna systems, including the **Buddipole**, Mini-Buddipole, Buddistick PRO, and BuddiHEX, designed for rapid deployment and multi-band operation from 40 meters to 2 meters. Each product page details specifications, operational modes (dipole or vertical), and compatible accessories like tripods, masts, and baluns. The site also features portable DC power management systems such as the PowerMini 2 and PowerPlus, which include integrated battery chargers and solar controllers, catering to off-grid or field day setups. Instructional videos demonstrate antenna assembly, tuning, and deployment techniques for various configurations, including the VersaTee vertical and Mini-Buddipole. Customer testimonials and DXpedition highlights, such as operations from Montserrat (VP2M) and Dominica (J38), provide real-world examples of the equipment's performance in challenging environments. The company, established in 2001, emphasizes modularity, versatility, and efficiency in its product line, all manufactured in the USA. Shipping information, a 30-day return policy with no restocking fee, and contact details for their Heber City, Utah facility are clearly presented. The site serves as a direct sales portal, offering a comprehensive catalog of antennas, power solutions, and components for portable amateur radio enthusiasts.

Constructing a linear focus parabolic antenna for WiFi operation involves precise metalwork, as detailed in this project. The author, AB9IL, shares a build that can be completed in a few hours, emphasizing the hands-on process of shaping and assembling metal components. This design aims to provide enhanced signal range for 2.4 GHz wireless networks, a common challenge in many ham shacks and home setups. The project outlines the practical steps required, from initial measurements to the final assembly, including cutting, bending, and bolting various metal parts. While specific gain figures are not provided, the parabolic design inherently offers significant _directional gain_ compared to omnidirectional antennas, making it suitable for point-to-point links or extending network coverage over distances. The construction process focuses on readily available materials and basic shop tools, aligning with the DIY spirit prevalent in amateur radio. This antenna project is presented as a straightforward build, requiring attention to detail in fabrication to achieve optimal performance.

Modifying the _ICOM IC-706MKII_ transceiver for out-of-band transmit capability involves specific surface-mount device (SMD) removal on the main circuit board. This procedure enables transmit functionality from 0.5 MHz to 200 MHz, excluding the commercial FM-Wide broadcast band, significantly expanding the radio's operational frequency range. The modification requires careful handling of small components and a fine-tipped, low-wattage soldering iron. Prior to beginning, all programmed memories and initial setup configurations must be noted, as the modification process will erase them. The instructions detail the necessary tools, preparation steps, and the precise location of the two SMD diodes to be removed. These diodes are situated near an oblong crystal can and a test point labeled _CP3_ on the main board. Successful completion returns the unit to its default configuration, necessitating manual reprogramming of memory channels and initial settings. This project is suitable for operators with experience in SMD work and fine soldering.

Constructing a Lindenblad antenna for 137MHz NOAA satellite reception involves specific design considerations for optimal performance. The resource details the use of 4mm galvanised steel fencing wire, 300-ohm television ribbon cable, and wood/plastic components for the antenna structure. Key dimensions for a 137.58MHz-resonant antenna are provided, derived from the ARRL Satellite Handbook, specifying s, l, w, and d as 42, 926, 893, and 654mm respectively. The antenna is designed for Right Hand Circularly Polarised (RHCP) signals, requiring the four folded dipole elements to be tilted clockwise by 30 degrees. A significant aspect covered is impedance matching between the antenna's 75-ohm impedance and a typical 50-ohm receiver input. A twelfth-wave matching transformer, constructed from 117mm sections of 50-ohm RG-58 and 75-ohm RG-59 coax with a 0.66 velocity factor, is described. The article also addresses coaxial cable and connector selection, recommending 75-ohm Type-N connectors for RG-6 cable in professional setups and F56/F59 connectors for general use, while strongly advising against PL-259/SO-259 connectors for VHF. Strategies for mitigating Radio Frequency Interference (RFI) are discussed, including antenna placement to shield from local TV transmitters and the use of commercial or DIY band-pass filters, such as cavity resonators or helical notch filters, along with ferrite chokes on coaxial cables. Antenna orientation is explored, noting the Lindenblad's 'cone of silence' directly overhead and its maximized sensitivity towards the horizon. An experimental vertical tilt of 90 degrees is presented as a method to improve overhead reception and reduce interference from strong horizontal signals, particularly relevant in high RFI environments like the Siding Spring Observatory site.

LOGvrr, a **freeware logging software** developed by IN3VRR, provides amateur radio operators with essential tools for managing their contacts. The resource details various downloadable components, including the core LOGvrr application, an international callbook with approximately 1.8 million callsigns, and utility programs for installation and data conversion. It supports functionalities like logging QSOs, managing awards, and interfacing with PacketCluster systems, with specific instructions for installation on Windows operating systems, including compatibility notes for Windows 10 and 11 using Hyper-V or DOSBOX. The site also offers external tools and documentation, such as the FAQ_VRR.PDF manual which covers installation, printer configuration, ADIF conversion, and Packet setup. It references third-party software like Mercurio and BV QSL Management for QSL printing, and ADIF2QSL for label printing, highlighting LOGvrr's ability to export QSOs in **ADIF format** for integration with services like LoTW. The resource includes historical updates, with the latest core component update in August 2014, and notes on the CallBook's maintenance up to 2015.

Presents the design and construction of the OK2FJ Bigatas, a portable, automatically tuned vertical antenna covering 80 through 10 meters. It details two distinct control systems: one utilizing BCD band data from Yaesu FT-857/897 transceivers, and another employing voltage level sensing for the Yaesu FT-817. The resource provides specific instructions for building the antenna's radiating element, loading coil with switchable taps, and the control circuitry, emphasizing the use of readily available components. The article outlines the physical construction of the antenna, including the use of duralumin tubes for the radiator and a PVC tube for the coil form. It specifies coil winding details, tap points, and the integration of radial wires for ground plane operation. The control electronics section provides schematics and component lists for both the BCD decoder (using a 74LS42 IC) and the voltage comparator (using an _LM3914_ bargraph driver), enabling rapid, automatic band switching without the minute-long tuning delays common in other systems. Crucially, the antenna achieves rapid band changes, with typical SWR values centered on common operating segments, such as **3.7 MHz** for 80m SSB. It also discusses modifications for CW operation on 80m and the trade-offs between antenna efficiency and full-range automatic tuning on higher HF bands, where manual adjustment of radiator length is suggested for optimal performance on 15m, 12m, and 10m. The resource includes construction photos and a discussion of cable requirements for reliable operation.

JJ0DRC's HF multi-band delta loop antenna project, initially conceived during the waning peak of Cycle 23, addresses the common challenge of achieving effective DX operation from a small residential lot in Japan. Dissatisfied with a ground plane antenna's performance in SSB pile-ups, the author sought a beam-like solution without a tower, drawing inspiration from a JJ1VKL article in CQ Ham Radio Sep. 2000. The antenna, constructed in October 2000, employs two 7.2-meter fishing rods (37% carbon fiber, reinforced with cyano-acrylate glue and aluminum tape) and 1mm enameled wire, fed by an Icom AH-4 external antenna tuner. While the exact beam pattern remains unmeasured, JJ0DRC observed a significantly higher callback rate compared to dipole antennas, particularly on higher bands. The system's circumference length of 15-20m is crucial for maintaining a good beam pattern across HF bands, though performance on lower bands like 80m, 40m, and 30m becomes less directional as the length deviates from a full wavelength. Ongoing maintenance addressed degradation issues, including aluminum tape cracking and wire breakage at connection points due to strong winds (often exceeding 10-15m/s in winter). The author reinforced rod connections with IRECTOR PIPE SYSTEM components and INSU-ROCK ties, and improved wire attachment methods using Cremona rope and epoxy bond to enhance durability.

This project outlines the construction of a 3-element reversible quad antenna specifically designed for the 40-meter band. The materials required include pushup towers, pressure-treated posts, insulated wire, and various electrical components such as relays and a balun. The construction process is straightforward, beginning with the installation of the posts in a straight line, followed by the assembly of the antenna elements and their elevation to the desired height. The antenna's design allows for directional signal reception, making it ideal for operators looking to enhance their communication capabilities on the 40-meter band. The project includes detailed instructions on tuning the antenna for optimal performance, ensuring that operators can achieve the lowest SWR possible. Additionally, the design can be adapted for other bands by extrapolating dimensions, providing versatility for amateur radio enthusiasts. Overall, this reversible quad antenna project is suitable for both beginners and experienced operators, offering a practical solution for improving signal strength and directionality in 40-meter communications.

The project outlines the process for constructing a low-power FM broadcast transmitter using a Raspberry Pi Zero, a simple wire antenna, and battery power. It details the software installation steps for PiFM and MPG123, essential for generating and transmitting audio. The resource provides instructions for configuring the Raspberry Pi to broadcast FM signals, including command-line operations for initiating transmission and playing audio files. It specifically focuses on the Raspberry Pi Zero's capabilities for this application, highlighting its cost-effectiveness and minimal hardware requirements. The content presents a practical, hands-on approach to creating a basic FM transmitter, suitable for short-range, experimental broadcasting. It includes guidance on testing the FM output and ensuring proper operation of the software components. The project emphasizes the use of readily available components and open-source software to achieve functional RF output.

Constructing a functional spectrum analyzer for the 0-100 MHz range presents a significant challenge for radio amateurs, often requiring specialized components and careful calibration. This project details a homebrew spectrum analyzer design utilizing common integrated circuits like the _SA605D_ FM receiver IC and _MAR-6_ MMIC amplifiers, aiming for a cost-effective solution. The design incorporates a low-pass filter, RF amplification, a voltage-controlled oscillator (VCO) for downconversion, and multiple IF stages at 150 MHz and 10.7 MHz, with a resolution bandwidth (RBW) of 15 kHz. Critical components such as the _SBL-1_ mixer and varicap diodes are specified, alongside instructions for winding inductors and tuning filters. The analyzer's performance is discussed in terms of input level limitations, specifically the 1dB-compression point and third-order intercept point, to ensure accurate measurements and prevent component damage. The _SA605D_'s logarithmic Received Signal Strength Indicator (RSSI) output serves as the detector, driving the Y-input of an oscilloscope, while a _TL084_ op-amp generates the sweep signal for the X-input. Potential enhancements include adding a step attenuator, improving front-end filtering, and implementing switchable IF filters for variable RBW, allowing for greater versatility in analyzing RF signals.

This page displays a 404 error, indicating the original content describing a simple _RS232 interface_ circuit is unavailable. The circuit was reportedly designed for older Kenwood transceivers and featured in chapter 22 of the _ARRL Handbook_. It likely involved basic electronic components for level shifting and signal conditioning between a computer's serial port and the radio's control interface. The intended project would have detailed the construction of a hardware interface, enabling CAT control for specific Kenwood models. Such interfaces typically convert TTL or CMOS logic levels from the radio to the +/-12V levels required by RS232, often utilizing ICs like the MAX232 or discrete transistor circuits. While the specific schematics and bill of materials are absent due to the page error, the context suggests a DIY electronics project for enhancing legacy amateur radio station functionality through computer control.

HD Communications Corp specializes in **RF and microwave amplifiers** engineered for demanding communication, defense, and industrial applications. Their product line includes precision-built, high-power solutions, along with RF connectors, filters, HF cables, and various accessories. The company also supplies tower hardware, valves, and tubes, catering to a broad spectrum of radio frequency infrastructure needs. Beyond amplifiers, HD Communications offers a range of **RF filters**, including low-pass filters, antenna filters, and solutions for RFI/TVI mitigation. Their inventory encompasses essential components like coaxial cable and various connector types, supporting both amateur radio and professional installations. The company operates as a manufacturer and vendor, providing direct sales of its specialized RF products.

The Icom IC-7300 is a popular HF transceiver among amateur radio operators, known for its advanced features and performance. This modification guide focuses on enabling extended transmission capabilities, specifically for MARS and CAP frequencies. The instructions are based on the work of PA2DB and include detailed steps for removing specific diodes to unlock additional frequency ranges. Before proceeding with the modification, users are advised to take necessary precautions, such as ensuring the radio is powered off and using ESD protection. The guide emphasizes the importance of using appropriate soldering techniques and tools to avoid damaging sensitive components. A video demonstration is also provided to assist users visually in performing the mod. While this modification can enhance the functionality of the IC-7300, it is crucial to note that it may void the warranty and should be undertaken at the operator's own risk. The guide serves as a valuable resource for those looking to expand their operating capabilities with this versatile transceiver.

Ferrite Toroids. Iron Powder Toroids. Ferrite Beads. Split Cores. Cable clamp-ons. Balun Cores. W2FMI Baluns and Ununs. Inductive components for EMI Suppression and RFI Suppresion, power supplies, HAM radio.

SSB-electronic gmbh based in Germany produces coax cables and connectors, rf parts and components, SDR receivers and transceivers, transvertes, attenuators, coax relays, precision directional couplers.

About beverage antennas, Enhanced F/B Beverages, Bandwidth of Directivity, arrays. This article describes two phasing systems for Beverage antennas that improve directivity and cancel rearward signals. These systems use lossy elements and require minimal components to achieve broadband performance.

TX RX Systems Inc. offers a robust catalog of RF conditioning products, including **transmitter combiners**, receiver multicouplers, and various RF filters. Their extensive experience, spanning over 45 years in the RF and Land Mobile Radio (LMR) industries, underpins their specialized offerings. They provide solutions for in-building RF coverage, repeater systems, and general RF management, catering to the demanding requirements of professional radio communications. Their product line features **bidirectional amplifiers (BDAs)**, signal boosters, and cavity filters, essential components for optimizing radio system performance. The company emphasizes reliable solutions, leveraging decades of field-proven expertise in designing and manufacturing critical RF infrastructure. From duplexers to cell enhancers, TX RX Systems focuses on delivering high-quality RF components and integrated systems designed to ensure clear and consistent radio signal integrity across diverse operational environments.

The Collins TRC-75 autotune linear amplifier, owned by JF2SVU, is presented with a focus on its internal modifications. This QRO amplifier utilizes three 4CX250 tubes in parallel for its final stage, delivering 1 KW output power. Notably, the amplifier achieves full power with only 100 mW of RF input, a characteristic often associated with Collins designs. The original 400 Hz power supply has been converted for easier shack integration, and the entire RF and power supply sections have been rehoused into a compact, clean enclosure. The control unit, positioned above the amplifier, features three meters for individual vacuum tube IP monitoring and a multi-meter on the right. A dedicated 7 MHz receiver, recently completed, is also part of this integrated system. The autotune functionality means the main amplifier unit only requires connections for power, control, and coaxial cables, simplifying its operation. Key components like the 4CX250 tubes and NF capacitors are visible, along with the gearing mechanism for the final tank circuit. A timer and relay system manages high-voltage delay and cooling fan off-delay, although the cooling fan's airflow is noted as somewhat insufficient. A central volume control, which experienced a contact issue, is also highlighted.

Accurately determining an antenna's feedpoint impedance is crucial for optimal performance, especially when experimenting with new designs or making adjustments. While SWR meters provide basic information, a full complex impedance measurement reveals the resistive and reactive components, which are essential for proper matching. Modern antenna analyzers, like the _Palstar ZM30_ or MFJ259B, simplify this task, but measurements taken through a transmission line require careful interpretation due to impedance transformation. This resource details a calibration method to precisely account for the effects of the feedline. It explains how a transmission line can significantly alter the measured impedance, illustrating this phenomenon with a Smith Chart example where an 80m antenna's [22 + j6] Ohms feedpoint impedance transforms to [82 + j45] Ohms after a 10m line. The guide demonstrates using a transmission line calculator applet, such as the one by W9CF, to reverse this transformation. It outlines the process of calibrating a specific length of RG174 coax, showing how an initial 26ft estimate was refined to **25.85ft** to accurately predict a known 22 Ohm load, significantly improving accuracy over uncalibrated results.

RFAC Solutions specializes in providing a range of RF components, including various connector types, cable assemblies, attenuators, and filters. Their product line features common connector standards such as SMA, BNC, TNC, N-Type, MCX, and MMCX, essential for reliable RF signal paths in amateur radio and commercial applications. The company also offers high-power VHF amplifiers, catering to needs for signal boosting in specific frequency ranges. Their offerings extend to dust caps and adapters, which are crucial for maintaining the integrity and versatility of RF systems. The focus on supplying components from South Korea suggests a commitment to specific manufacturing standards and supply chain practices. This resource details a vendor's product scope, useful for hams sourcing specific parts for shack builds or antenna projects. Jeff is listed as a contact for inquiries.

Radio frequency systems require robust protection against transient voltage events, which can severely damage sensitive equipment. This resource details a range of **RF surge protection** devices, including models with DC Pass, DC Block, Bias T, and Ultra Low PIM characteristics, designed to safeguard critical infrastructure. It also presents various RF filtering solutions and interconnect components, emphasizing their role in maintaining signal integrity and operational continuity across diverse applications. The site provides information on products engineered for both RF and data line protection, highlighting their utility in preventing downtime and equipment loss. Specific product categories encompass coaxial protectors, grounding items, and fiber optic solutions, indicating a broad scope of application from amateur radio installations to industrial and telecommunications networks. Furthermore, the resource mentions the availability of NOM-certified products and offers same-day shipping for many items, underscoring a commitment to rapid deployment and compliance with industry standards.

Industrial Communication Engineers (ICE) was a manufacturer specializing in **RF components** and solutions for amateur radio and commercial applications. Their product line included a range of RF parts, various types of filters, and RF switching products designed to enhance station performance and mitigate interference. These components were critical for hams engaged in contesting, DXing, or general operating, providing means to improve signal integrity and manage complex antenna systems. The company's offerings addressed common operational challenges such as RFI and TVI, with products like **low pass filters** and antenna filters. While the specific technical specifications of their product range are no longer available, such components typically provided significant attenuation of unwanted harmonics and out-of-band emissions, crucial for maintaining a clean signal and preventing interference with other electronic devices. The current status indicates the domain is for sale, suggesting the manufacturing operations have ceased.

Hidden transmitter hunting, often called fox hunting or Amateur Radio Direction Finding (_ARDF_), presents a unique challenge for radio amateurs. This resource details the _PicCon_ controller, a specialized device designed to automate the transmission of signals for such events. It integrates with a standard radio transceiver, functioning similarly to a packet radio TNC, by controlling the Push-To-Talk (PTT) line and injecting audio tones or modulated CW Morse code into the microphone input. The _PicCon_ unit is field-programmable using DTMF tones received via the radio, storing all settings in EEPROM for power-off retention. Its compact design and low power consumption (a few milliamps from a 7-35VDC source) make it suitable for remote deployment. An onboard LED indicates operational status, and a push-button allows manual start/stop of transmissions without DTMF. Typically supplied as a kit, _PicCon_ includes a PCB, components, and a comprehensive manual (available in HTML, RTF, and PDF formats). The kit provides a six-conductor interface cable, but users must supply radio and power plugs due to varied configurations. Byon, _N6BG_, developed this controller, which is available from the Byonics website.

Presents a QRP AM/CW transmitter project specifically designed for the 10-meter band, utilizing a crystal oscillator and a collector-modulated AM oscillator. The design employs a 2N2219(A) transistor in a Colpitts configuration, generating 100 to 350 mW of RF output power depending on the 9-18 Volt supply voltage and modulation depth. Frequency stability is maintained by a 28 MHz crystal, with fine-tuning possible via a Ct1 trimmer capacitor for approximately 1 kHz adjustment. The resource details the RF oscillator stage, implemented with a 2N2219 NPN transistor, emphasizing frequency stability and low power dissipation. It also covers the amplitude modulation stage, managed by a 2N2905 PNP transistor, which impresses audio information onto the carrier. Selective components (C3, C4, C7, C5) enhance voice frequencies within a +/- 5 kHz bandwidth, and modulation depth is controlled by R2 and R3. The project includes a 3-element L-type narrow bandpass filter (Ct3, L3, C10) to suppress harmonics and ensure a clean output signal. The project provides a complete schematic diagram, a comprehensive parts list including specific capacitor, resistor, and inductor values, and construction notes for the coils (L1, L2, L3). It also offers practical advice on enclosure requirements, suggesting an all-metal case or a PVC box with graphite paint for RF shielding. Operational parameters such as current draw (27mA@9V to 45mA@16V) and input impedance (50 Ohms) are specified, alongside guidance on antenna matching and the importance of a valid amateur radio license for 10-meter band operation.

Electronic components dealer stocking RF adapters and many other popular items.

Showcasing a specialized product line, Advanced Receiver Research presents a comprehensive catalog of **low noise preamplifiers** and microwave **Gunnplexers**. The offerings span a broad spectrum of radio frequencies, from VLF, LF, MF, and HF bands up through VHF, UHF, and microwave, catering to diverse applications including amateur radio, commercial installations, and military systems. Their product range includes mast-mount preamplifiers, inline attenuators, power dividers, and various coaxial components. My own experience with similar low-noise front ends for weak-signal work on 2 meters and 70 centimeters underscores the critical role such components play in maximizing receiver sensitivity, especially when chasing distant DX or engaging in EME. The detailed product descriptions and technical specifications provided on the site allow operators to select the optimal preamplifier for their specific band and noise figure requirements, essential for improving signal-to-noise ratio. The site also lists specialized products for unique applications like Nuclear Magnetic Resonance (NMR) and Studio Transmitter Links (STL), demonstrating a depth of engineering capability beyond typical amateur radio fare. This breadth of offerings, coupled with clear ordering and warranty information, positions Advanced Receiver Research as a key supplier for high-performance RF components.

Demonstrates the adaptation and construction of a 7-element DK7ZB Yagi antenna for the 4-meter band (70 MHz), utilizing components from a defunct 2-meter CUE DEE Yagi. The resource details the modifications made to the original DK7ZB design to fit the shorter CUE DEE boom length, specifically adjusting element lengths for 6mm rod elements while reusing existing mounting holes for the reflector and last director. It provides precise element lengths for the reflector, dipole (12mm aluminum tube), and five directors, along with a note on cutting elements for transport. The article includes a 4NEC2 simulation file for performance analysis and an SWR plot, confirming the antenna's electrical characteristics. It also specifies the calculation for the quarter-wavelength matching cable using SAT752F coaxial cable, resulting in a 909mm length. Practical application is shown with the finished antenna in operation at JO20XC, listing several activated Maidenhead squares such as JO56PA and JP40KS, validating its effectiveness for portable 70 MHz operations.

Demonstrates the construction of a custom programming cable for Yaesu VX-7R and VX-5R handheld transceivers, enabling computer interfacing for memory management and frequency coverage adjustments. The resource details a six-transistor circuit design, powered by the computer's RS232 interface, utilizing readily available and inexpensive discrete components. It includes a complete bill of materials, specifying transistors like the _2N2222_ and _2N3906_, diodes, and resistors, along with a matrix board layout for compact assembly within a 75x50x25mm enclosure. The guide provides practical tips for working with matrix board, such as scoring and snapping, track cleaning, and component soldering order. It outlines the specific connection requirements for both the VX-7R (via Yaesu's CT-91 breakout lead with a 2.5mm stereo jack) and the VX-5R (via CT-44 or a four-section jack), detailing signal and ground pinouts. The author successfully tested three circuits, documenting the one with complete two-way communication, allowing users to program their rigs with software like _VX-7 Commander_ and achieve capabilities beyond commercial cables, including band adjustments.

1500 watts PEP output from a Kenwood TL-922 amplifier requires careful attention to parasitic suppression and component selection to ensure stability and longevity. This resource critically examines common modifications, often based on anecdotal evidence rather than sound engineering principles, that can degrade performance or introduce new issues. It highlights how replacing aged components often gets misattributed to the efficacy of unnecessary modifications, leading to widespread misinformation within the amateur radio community regarding amplifier stability. The article details specific, effective modifications for the TL-922, such as shortening anode-to-chassis and anode-to-grid paths to improve VHF stability and efficiency. It addresses issues like incorrect capacitor types in the tank circuit, inadequate grid grounding, and poor RF sheet metal design, providing practical solutions like adding direct ground connections for the plate tune variable capacitor. The author also discusses proper parasitic suppressor design, emphasizing the importance of lead length and component selection for optimal performance and harmonic suppression, contrasting these with less effective or detrimental 'magical suppression kits'.

Protecting amateur radio equipment from transient overvoltages requires robust lightning and surge protection, which is the focus of Electronic Specialty Products. The company provides various devices, including coaxial lightning arrestors for antenna feedlines and surge protectors for AC power lines and data circuits. These devices are engineered to divert high-energy surges, such as those caused by direct or indirect lightning strikes, away from sensitive transceivers, amplifiers, and computer components, thereby preventing catastrophic damage. Key products include the _Coaxial Lightning Protector_ series, designed for various impedance levels and frequency ranges up to 3 GHz, and the _AC Line Surge Protector_ for shack power distribution. Effective deployment of these protection devices can significantly reduce the risk of equipment failure and ensure operational continuity during severe weather. For instance, a properly installed coaxial arrestor can handle peak currents of **20 kA**, while AC line protectors offer clamping voltages typically below 400V. Comparing different models reveals varying levels of insertion loss and return loss, with some coaxial units exhibiting less than 0.1 dB loss at 500 MHz, making them suitable for high-performance HF and VHF/UHF operations. Integrating these components into a comprehensive grounding system is crucial for achieving maximum protection against both common-mode and differential-mode surges.

The article details a specific method for performing maintenance on a crank-up tower, focusing on cable and rotator replacement without a full power pulldown. It outlines the necessary equipment, including a 2-section extension ladder with a horn attachment and a two-piece, 6-foot steel pipe, specifying a 1 1/4-inch diameter. The procedure involves lowering tower sections onto the internal pipe to slacken cables, allowing for their removal and replacement, and also describes how to replace the rotator while the tower remains upright. Key steps involve using the pipe to support tower sections, enabling access to the cables and bearings. The author, N5AR, emphasizes safety by instructing the reader to remain on the ladder at all times, rather than climbing the tower itself. The process is presented as manageable for a single operator, with the author having successfully completed the task on a _UST TX472_ tower. Specific tools mentioned include Allen wrenches and end wrenches for cable ends and bearing bolts. The method provides a practical approach for tower upkeep, minimizing the complexity often associated with such tasks and allowing for maintenance of components like cable pulleys and their bearings.

A system designed to automatically tune small transmitting magnetic loop antennas, particularly beneficial for **contest operations** where rapid frequency changes are common. The core of the system involves a PC-based control application, AutoCap, written in C#, which monitors antenna SWR via an external meter and commands a motor interface to adjust the loop's variable capacitor. The software is compatible with Windows and Linux via the Mono framework, offering a graphical user interface for monitoring system status, SWR, power, and motor commands. Key components include one or more magnetic loop antennas equipped with DC or stepper motors for capacitor adjustment, an SWR meter with data output (such as the Telepost LP-100A or a homebrew serial/USB SWR meter), the AutoCap PC software, and a motor interface. The most effective motor interface utilizes an **Arduino-based controller** with custom firmware, providing precise control over both simple DC motors and stepper motors, and supporting features like motor braking for finer adjustments. The system allows for configurable SWR thresholds, pulse widths, and motor effort settings to optimize tuning speed and resolution. Optional radio integration provides frequency hints, enabling the algorithm to learn the relationship between motor actions and resonant frequency, thereby speeding up initial tuning responses. The software also supports antenna profiles, allowing operators to save and recall specific configurations for different loops, including accumulated frequency hint data.

Benelec Pty Ltd specializes in the design and manufacturing of **antennas** and RF components, covering a broad frequency range from 0.002 GHz to 8 GHz. Their product line includes Land Mobile Radio Antennas, such as HF 2-30MHz, VHF 40-180MHz, and UHF 200-520MHz models, alongside specialized Military Antennas for dismounted, UxS, C2, and EW applications. The company also produces Cellular Antennas, including 4G/5G and GPS/GNSS types, and Marine Antennas for both vessel-mounted and fixed-site installations. Additionally, Benelec offers a comprehensive range of coaxial cables, connectors like N-Type and SMA, and various radio accessories. The company's offerings extend to RF components such as duplexers, diplexers, and 50 Ohm loads, as well as DAS components like directional couplers and hybrid combiners. Benelec provides EMP and lightning protection solutions, including 1/4 Wave Stub protectors and replaceable GAS capsules. Their product catalog also features P25, DMR, and FM Analog radios, along with portable and mobile radio accessories like batteries, chargers, and cabled headsets. The company supports various sectors with robust communication solutions.

Mitigating RF noise in a mobile operating environment, particularly within a _Jeep TJ_ vehicle, presents unique challenges due to the vehicle's electrical system and chassis characteristics. This resource details practical methods for identifying and suppressing various forms of radio frequency interference (RFI) that can degrade receiver performance for both CB and amateur radio transceivers. It covers common noise sources such as ignition systems, alternators, fuel pumps, and computer modules, explaining how these components generate broadband or specific frequency noise that impacts radio communications. The guide offers actionable solutions, including proper grounding techniques, the strategic use of ferrite beads and toroids on power and data lines, and the installation of bypass capacitors. It discusses the effectiveness of different filtering strategies for DC power lines and antenna feedlines, illustrating how a clean power supply and shielded cabling can significantly reduce conducted and radiated noise. The information presented helps operators achieve a lower noise floor, improving signal-to-noise ratio and enabling clearer reception of weak signals, which is crucial for effective mobile DXing or local ragchewing.