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FSQ is a Fast Simple QSO mode designed specifically for HF. It works well under NVIS and sunrise/sunset conditions on the lower bands, and also works well for short skip and grey-line on higher bands and can be used also on VHF FM.

This antenna is reported as being lower noise than conventional yagis and had a very low SWR for 500 KHz.

Learn how to easily build a 10-meter vertical antenna, perfect for DX contacts on the amateur radio bands. This flowerpot or T2LT design is portable, efficient, and ideal for ham radio operators looking to improve their DX performance. With just a few basic tools and materials, you can construct this antenna for portable operations or as a home station setup. Discover how to set up the antenna, improve its performance by raising it higher, and start making contacts with stations around the world. Watch a step-by-step guide on YouTube for building and testing this DIY ham radio antenna.

Choking balun for lower HF and MF bands. (1.8MHz - 10MHz). Requiring a choking balun to isolate the potential RF pick up on the coax cable as it runs past equipment such as computer within the radio room at lower HF and MF frequencies a simple method of winding RG58 coax onto a Powdered Iron Toroid Core was constructed.

Learn how to easily improve your handheld VHF performance on the 2-meter band with the Flowerpot antenna. This simple DIY antenna made from coaxial cable requires minimal tools and materials, providing a big range upgrade compared to standard rubber-duck antennas. Discover how to build, tune, and optimize the Flowerpot antenna for excellent performance. Ideal for hams looking for lightweight, portable solutions for handhelds, mobile rigs, home stations, SOTA/POTA activations, and emergency communication.

Operating an amateur radio station effectively requires reliable coaxial cable to minimize signal loss between the transceiver and antenna. SIVA Cavi, an Italian manufacturer, produces a range of coaxial cables, including specific 50 Ohm low-loss types suitable for amateur radio applications. Their product line features cables like **RG 58 SHF1**, **RG 213 SHF1**, and **RF 400 SHF1**, which are commonly deployed in HF and VHF/UHF setups. The company also offers specialized cables such as the **HF 214 UF Ultraflex**, a high-performance broadband low-loss 50 Ohm cable designed for flexibility and reduced attenuation across various amateur bands. These cables are engineered with solid or foam dielectric materials, impacting their electrical characteristics and suitability for different power levels and frequency ranges. For instance, foam dielectric cables often exhibit lower loss at higher frequencies, a critical factor for VHF/UHF operations. Beyond amateur radio, SIVA Cavi manufactures cables for digital video broadcast, offshore marine use, and fire detecting systems, demonstrating a broad engineering capability in coaxial cable technology.

This article introduces an Arduino-based QRP CW Transceiver designed for lower HF bands. The journey begins with the Wotduino, evolving from a keyer to a multi-mode beacon. The development includes a QRP transmitter and culminates in a receiver inspired by Roy Lewallen design. The transceiver, controlled through a control bus features a signal path, modulation, filtering, and adjustable frequency settings. Despite initial testing intentions, successful QSOs on 80 and 40 meters showcase its functional capabilities.

This project revisits a minimalist software-defined radio (SDR) receiver built using a Raspberry Pi Pico, now optimized for simplicity and affordability. Designed for breadboard assembly with through-hole components, the receiver covers 0–30MHz, supporting CW, SSB, AM, and FM modes with an OLED display and spectrum scope. Key improvements include enhanced frequency accuracy, reduced op-amp saturation, and lower-cost components. Powered by three AAA batteries, it delivers standalone operation for global signal reception. Ideal for hobbyists, the design fosters experimentation and is documented with firmware and schematics available online.

The Shiawassee Amateur Radio Association (SARA), operating under the call sign W8QQQ, serves as a non-profit amateur radio organization in lower central Michigan's Shiawassee County. Its primary objectives include public service, emergency communications, and advancing amateur radio through education and technical excellence. The club maintains a weekly _Skywarn_ 2m net on the N8VDH repeater at 147.02 MHz (+.6 MHz, 100 Hz tone) every Monday at 7:00 PM, actively seeking more local hams to participate. SARA also facilitates VE testing, with upcoming sessions like the one scheduled for April 23, 2026, at 6:30 P.M., requiring pre-registration by April 20. SARA holds monthly meetings at the James P. Capitan Building in Corunna, typically on the second Tuesday of each month at 7:00 PM local time, excluding December's social event. They offer Zoom meeting options for members unable to attend in person. Annual dues are $15.00, with a reduced rate for new licensees, making it a very low-cost club. The organization actively seeks more EMCOMM assistance from all Shiawassee County hams, not just club members, to bolster their ARPSC (ARES/RACES) capabilities, noting that only about **10** out of **200+** county hams are currently active in ARES. They also maintain a Google Group, "W8QQQ," for electronic notifications and club communications.

A Trapped dipole inverted V antenna for lower HF Bands. Construction details are for temporary installation. Permanent installations will require additional ruggedising and waterproofing however the basic electronics concepts remain the same. This project includes SWR plots for the three bands and pictures details of the homemade traps.

An cheap and efficient wire antenna for lower HF bands. This closed loop antenna, radiates perpendicular to its plane with a bi-directional radiation pattern. With a gain of 2 dB over a diplole it is a low noise sensible antenna. Requires a tuner if you want to use as a multiband antenna.

Filter Free is the shareware version of Filter Solutions and Filter Light. Filter Free is limited to 3rd order or lower low and high pass filters, 2nd order or lower band pass and band stop filters, and 10 tap or lower FIR filters, and does not include most of the advanced design capabilities of Filter Solutions and Filter Light.

This study details a reception comparison between vertical and horizontal active loop antennas, specifically two identical _Wellgood active loop antennas_, on various HF bands. The experiment, conducted in a densely populated QRM-prone area, monitored FT8 signals over a 24-hour period using two identical receivers. The methodology involved direct comparison of signal reception across the HF spectrum, aiming to identify performance differences based on antenna orientation. The results indicate that vertical loops demonstrated superior performance on higher bands (10m, 15m, 20m), while horizontal loops excelled on lower bands (30m, 40m, 160m), particularly for receiving long-distance (DX) signals. The horizontal loop's advantage on lower bands is attributed to potentially better low-angle performance and reduced sensitivity to man-made noise, yielding a **2-3 S-unit** improvement on 160m. The study provides practical insights for optimizing antenna placement in challenging urban environments, noting that the horizontal loop consistently showed a **10-15 dB** signal-to-noise ratio improvement on lower bands.

A 10-meter half-wave vertical antenna, designed by Thomas 4L/G8BAG, offers a practical solution for hams with limited space and materials. This "flower pot" design utilizes common hardware store items such as 60mm plastic drain pipes and 75 Ohm coax cable, demonstrating that effective HF operation doesn't require specialized components. The author details the coax preparation, including stripping the outer sleeve and braid at specific measurements like **2510 mm** and 2450 mm, and integrating it into the pipe structure. The construction emphasizes simplicity and low cost, providing an accessible path to getting on the air on the 10m band, especially when a horizontal beam is not feasible. The article notes an SWR of _1.5:1_ with 75 Ohm coax, managed by an MFJ 258 for impedance matching. This temporary solution proved robust, withstanding various weather conditions and achieving contacts across continents, including W, VK, BG, G, JA, and VR2, using 100W SSB from Georgia.

Documents the design and construction of a **four-band Moxon beam** antenna, covering 20, 15, 10, and 6 meters. Author W7JMP shares his journey from initial research and computer modeling using 4NEC2 to the final on-air testing and optimization. The project aimed for gain over a dipole on 20 meters, with a budget under $500, including the antenna rotor. The design incorporates fiberglass spreaders and a single feedpoint, avoiding complex relay switching. The article details the selection of materials, assembly techniques, and the critical tuning process. W7JMP describes fabricating the hub, mounting spreaders, and attaching elements made from stripped THTN wire. A notable innovation is the use of a half-wave tuning stub with a loading coil for in-situ adjustment of the 20-meter reflector, optimized via remote S-meter readings using a webcam and smartphone. This method allowed for fine-tuning the **front-to-back ratio** without lowering the antenna. Initial testing revealed a dipole-like pattern, which was significantly improved after tuning, resulting in reported 2 to 4 S-unit front-to-back ratios and enhanced signal strength for DX contacts on multiple bands, including sporadic E on 10 and 6 meters.

This article explores the conventional wisdom about antenna height in amateur radio operations, challenging the common belief that "higher is always better." Through practical examples and computer modeling, it examines how low-height antennas like Beverage antennas, VP2E, and End-Fed Half Wave (EFHW) configurations can perform effectively in various scenarios. The analysis includes radiation patterns and efficiency considerations for antennas at different heights, particularly focusing on portable operations. The article demonstrates that while height affects antenna performance, lower installations can still provide practical and efficient solutions for specific applications, especially in portable and QRP operations.

Demonstrates the ZS6BKW multiband HF antenna, a design by ZS6BKW (G0GSF) that improves upon the G5RV by offering direct resonance on multiple bands without an antenna tuner. The resource details the antenna's 90-foot length and 40-foot 450-ohm twin lead downlead, emphasizing its suitability for hams with limited space or budget. It covers both horizontal and inverted-V configurations, noting the inverted-V's single-support advantage and the importance of maintaining an apex angle of at least 90 degrees to prevent signal cancellation. The author, G3UKV, shares his preference for 450-ohm twin lead over 300-ohm due to its superior strength and lower losses, especially in wet conditions, drawing from his extensive field experience. The document presents recorded SWR and impedance (R) measurements taken with an MFJ Antenna Analyzer, confirming excellent performance on 40m, 20m, 17m, 12m, 10m, and 6m, often with SWRs below 1.3:1. It also discusses the antenna's tunability on 80m with an ATU and suggests a method for 160m operation. G3UKV recounts receiving "excellent reports" on 7 MHz and 14 MHz, validating the antenna's effectiveness. Practical advice includes keeping antenna ends clear of ground by at least a yard to avoid detuning and the recommendation of a 1:1 current balun where the 450-ohm feeder connects to 50-ohm coax.

A vertical delta loop is a practical antenna for low bands, popular for its simple design requiring just one support. Its shape, an equilateral triangle in free space, yields optimal gain and radiation resistance. Deviating from this shape lowers performance. The delta loop can be polarized either horizontally or vertically based on the feed point location. In vertical polarization, it acts as two quarter-wave verticals with the baseline feeding one side. This design minimizes radiation from the baseline while maintaining effective operation.

The Butternut HF2V, originally a two-band vertical antenna for 80m and 40m, was enhanced by the user to include 30m and 20m bands for better digimode DX work during the solar minimum. The additions used components adapted from the HF6V and innovative methods for the 20m addition, either through a parallel vertical element or a lower-mounted independent element, minimizing band interaction. This modified four-band antenna now supports high power across popular HF bands using a single feedpoint.

Presents the digital edition of "The Communicator," a journal from Surrey Amateur Radio Communications (SARC), offering a curated collection of articles, technical deep dives, and operational reports. Each issue, such as the July-August 2026 edition, details specific **homebrew projects** like an NTP Dual Clock, a True RMS to DC Converter, and an Arduino NANO automation mod for the Yaesu FH-2. It also covers historical accounts, including the legacy of SSB pioneer Nicolaas Kooman and the mystery of the Lagercrantz suitcase radio, alongside practical operating advice and contest summaries like Field Day 2026 and the RAC Canada Day contest. The journal consistently features diverse content, from exploring the capabilities of modern transceivers like the Icom IC-9700 for digital modes to discussions on antenna theory, such as building a vertical HF antenna without radials. It also addresses contemporary issues, exemplified by an article unpacking the FAA's "CW interference" directive concerning Boeing 787 transponders, clarifying that the interference is not related to amateur radio Morse code but rather unmodulated carrier signals impacting aviation frequencies around 1030 MHz and 1090 MHz. Furthermore, the publication includes lighter fare like "No-ham Recipes," club meeting minutes, and member profiles, providing a holistic view of the amateur radio community. It offers multiple access options for each issue, including full and lower-resolution PDF downloads, an online magazine reader, and an experimental AI-LLM audio podcast version, making its extensive content readily accessible to a global audience in over 165 countries.

This project addresses the need for a 50 MHz Amplifier providing substantial power for Australian "Advanced Licensees" permitted to use 400W PEP in the 52-54 MHz band. In regions limited to 100W PEP due to TV channel usage, this initiative aims to enhance power output for transceivers with lower capabilities on the 6m band.

Demonstrates practical **rules of thumb** for selecting and utilizing ferrites and coils in amateur radio projects, particularly for RF applications up to 30 MHz. It addresses common challenges like determining appropriate ferrite grades and estimating L/C values without precise specifications. The resource details the author's experience with readily available grey ferrites, noting their suitability for HF work, and provides guidance on constructing **baluns** and RF chokes, balancing inductance for lower frequencies against inter-wire capacitance for higher frequencies. It also outlines a method for estimating power handling based on ferrite weight, suggesting a 1-gram ferrite can manage over 2 Watts, and offers a technique for evaluating unknown ferrites by winding 10 turns and measuring resonance with a 1 nF capacitor. This approach emphasizes a hands-on, iterative method for balun winding and adjustment, allowing operators to quickly approximate component values. The article compares the characteristics of ferrite-cored coils with air-cored coils, highlighting the reduced pickup and radiation of ferrite designs. It refines the air-coil estimation method for frequencies between 2.5 MHz and 10 MHz and provides a scaling factor for frequencies outside this range, aiming to get operators into the correct general area for their designs. The author's standardized ferrite choice (RND Components 165-00182) is presented as a practical example for reproducible projects.

Four _Headway 38120_ LiFePO4 cells form the core of an 8AH 12V battery pack, designed for reliable emergency and field power in amateur radio operations. These batteries offer significant advantages over traditional lead-acid types, including a lifespan up to **10x** longer in charge/discharge cycles, lower internal resistance for faster recharging, and a flatter discharge curve that maintains voltage stability during use. Their inherent safety, being a flame-retardant technology, makes them a preferred choice for portable applications. Proper configuration, including parallel/serial setups, and careful charging/discharging protocols are crucial for maximizing battery life. Each cell has a nominal voltage of 3.2 volts, with a maximum charge voltage of 3.65 volts. A Battery Management System (BMS) is highly recommended to prevent overcharging or deep discharging, safeguarding the cells. The project emphasizes safety, noting the batteries' high short-circuit capacity of **200 AMPS** and the critical importance of incorporating an inline fuse between the battery pack and the load. Components like the battery holder, buss bars, and a suitable case are also detailed.

The recognition of telegraphy masked by noise at 40 and 80 signs/min telegraphy speed was studied in 10 normal-hearing subjects at different sound pressure levels (25-85 dB SPL in steps of 5 dB) as well as at different test frequencies (2000, 1000, 800, 630, 500 and 250 Hz). The ability to recognize the signs varied with varying SPL. Recognition for most of the subjects was best at an SPL close to 70 dB. All subjects improved their recognition as the frequency was lowered to 500 Hz, some even at 250 Hz. These facts should be taken into consideration when training telegraphy operators as well as in the construction of radio receivers to permit listening at low frequencies. Furthermore, the critical ratio was calculated at the different test frequencies.

Single Sideband (SSB) operation requires careful attention to the relationship between a radio's displayed frequency (suppressed carrier) and the actual 3 kHz wide audio signal. This resource clarifies how Upper Sideband (USB) and Lower Sideband (LSB) signals occupy spectrum above or below the indicated frequency, respectively. It provides practical examples for General Class operators on the **20m** and **40m** bands, such as setting a VFO to 14.226 MHz for USB on 20m or 7.178 MHz for LSB on 40m, to maintain a safe margin from band edges. The resource emphasizes the critical importance of staying within allocated band limits to prevent out-of-band emissions, particularly when operating close to band edges. It includes relevant excerpts from **FCC Regulation Part 97**, specifically section 97.307, which details emission standards, necessary bandwidth, and spurious emission attenuation requirements. The text explains that unused sidebands are considered spurious emissions and notes that modern HF equipment typically exceeds the 43 dB spurious emission reduction standard, often achieving 60 dB or more.

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.

This document provides comprehensive guidance on modeling and constructing multiband dipole antennas using traps. It addresses common segmentation issues in EZNEC modeling software, recommends optimal segment lengths for trap models, and compares trapped dipoles with paralleled multiband dipoles. While trap dipoles are significantly shorter, they exhibit lower gain and narrower bandwidth. Detailed instructions for building weatherproof coaxial traps include material lists, construction steps, and tuning methods. The guide notes that properly constructed coaxial traps introduce only minimal signal loss (0.6 dB) while offering practical multiband performance in a compact design.

The Big Gun's Guide" is a comprehensive exploration of low-band propagation, aimed at serious Amateur Radio operators. It delves into the complex physics of the ionosphere at lower frequencies, contrasting it with HF propagation. The book covers essential topics like ionospheric fundamentals, propagation mechanisms, magneto-ionic effects, and disturbances. It also addresses the challenges of low-band DXing and provides insights for overcoming them. Brown's work is detailed and technical, offering valuable knowledge for those seeking to master the intricacies of low-band communication

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.

Rob Conklin N4WGY delivered an informative presentation on Hexagonal Beam antennas (Hex Beams), detailing their construction, performance, and benefits over traditional multiband Yagi antennas. He highlighted their cost-effectiveness, lower wind loading, lightweight design, and multi-band capabilities without requiring traps. Conklin also discussed the improved G3TXQ design, which offers better SWR performance across ham bands. The presentation included practical construction tips, resource recommendations, and demonstrations of performance analysis tools, making it a valuable resource for both novice and experienced antenna builders.

This website explains signal variations on a local radio net by tracking the foF2, a measure of ionosphere's ability to reflect radio waves. The website shows daily foF2 variations and how it affects Near Vertical Incidence Skywave (NVIS) propagation for local nets. It also considers D-layer absorption affecting lower bands and F2 MUF distance for long-distance communication. Additionally, the website tracks foEs for E-layer propagation and an EPI index for predicting Es chances.

Detecting stray RF voltages on station grounds, chassis, and interconnecting cables is crucial for preventing program and hardware failures in the shack. This article details the construction and application of an LED RF V-probe, which offers significantly higher sensitivity compared to conventional neon lamp indicators. The probe leverages two specific properties of modern red LEDs: their ability to glow at microampere currents and their rectification capability at frequencies up to tens of megahertz. The design features a simple circuit with two LEDs, allowing for indication of both positive and negative RF voltage half-waves. The minimum detectable RF voltage is approximately 2 V, a substantial improvement over the 40-60 V threshold of neon bulbs. The resource illustrates the probe's physical construction on a PCB and provides a direct comparison demonstrating its superior sensitivity in detecting RF fields near a coil. Two operational modes are described: a non-contact mode for high RF voltages (above 15-20 V) and a direct-contact mode for measuring lower RF voltages, with a safety caution for the latter. Practical examples show the probe's use in analyzing RF voltage distribution across a radio station setup at 1.84 MHz and 24.9 MHz, revealing insights into common-mode current issues and the effectiveness of mitigation strategies like adding radials.

This is a theoretical look at propagation on 630-Meters and 2200-Meters using ray tracing software. It expands on the brief discussion in the ARRL Handbooks. The Earth's magnetic field affects 630-Meter and 2200-Meter band propagation. Lower ionization reduces absorption, aiding low-frequency propagation. Differences exist between bands, limited daytime sky-wave propagation. Sunrise/sunset show promise, yet mechanisms are unclear. Ducting possible at night in specific conditions. Negative ions enhance propagation. Inefficient antennas and high man-made noise are anticipated. Groundwave propagation is significant on 2200-Meters.

Presents an online retail platform for amateur radio operators, showcasing a diverse inventory of equipment and accessories. The site lists popular transceivers such as the _Icom IC-7300_ and _Icom IC-7610_, alongside various antenna solutions including base, HT, mobile, and end-fed designs. Operators can find coaxial cable, including bulk options and products from "The Wire Man," essential for shack setup. The platform also stocks crimping and stripping tools, adapters, and power supplies, crucial for station maintenance and construction. Test equipment like _RigExpert Analyzers_ and accessories such as Daiwa meters and _West Mountain Radio_ Power Poles are available. Additionally, the site offers software from _Ham Radio Deluxe_ and _RT Systems_, catering to logging and radio programming needs. Shipping policies include free shipping on C.Crane Radios and most orders over $100.00 within the lower 48 states, providing clear purchasing incentives.

Illustrates the potential for radio frequency (RF) energy from amateur transceivers to interfere with vehicle electronics, drawing parallels to military _Radio Frequency Vehicle Stopper_ (RFVS) technology. The resource details personal experiences with VHF/UHF signals activating household devices and then pivots to the complexities of RF interaction with automotive systems, noting the development of multi-frequency RFVS (MFRFVS) to overcome vehicle-specific vulnerabilities. It highlights that while car manufacturers conduct RF immunity tests, the rigor varies, with luxury brands likely performing more extensive evaluations than others who merely meet minimal certification. The article explores practical considerations for mobile amateur radio installations, suggesting antenna placement over the car, using lower power output, and proper grounding to mitigate adverse effects. It acknowledges the lack of comprehensive data on RF/vehicle combinations but emphasizes that adherence to these basic principles can reduce risks. The author shares observations of unexplained car computer codes in a 2002 SUV, speculating on potential RF induction. Concerns are raised about the increasing complexity and interconnectedness of modern car electronics, including Bluetooth, remote access, and electronic control systems for critical functions like steering and braking. The article points out the diminishing space for third-party installations in contemporary vehicles and references the ARRL's stance on auto manufacturer policies regarding amateur radio installations, which generally advise against them.

The Pressure Paddle V2.0 simplifies the original 2019 design by using MOSFETs’ unique properties for reliable, minimalistic switching. When pressure sensors detect a press, they reduce resistance, activating the MOSFET and lowering voltage until it stabilizes at the MOSFET’s threshold. This ensures consistent “key down” signals for the transceiver. Compatible with 3-5V logic systems, the circuit operates independently of pull-up resistor size. The PCB is lightweight, easy to assemble, and can be packaged in heat shrink or mounted. This version maintains durability with fewer components and flexible packaging options.

The Spartan Sprint Special 40m CW Transceiver, originally documented in 2002 and reproduced in 2019, details a **QRP** direct conversion rig designed for portable operation. This project evolved from an experimental CMOS digital IC receiver, which proved too noisy for weak signals, into a dedicated 40-meter CW transceiver. The author, VE3SMA, aimed for reduced size, lower weight, and decreased receive current drain compared to earlier iterations, drawing on his extensive contesting experience and even his time operating million-watt transmitters at Radio Canada International. This compact transceiver delivers approximately 200 mW output, VFO-tunable over 15 kHz within the 40m band, and weighs a mere 73 grams (0.16 lb) including its balsa wood case. It features fast semi-break-in and sidetone, with a receive current draw of about 14 mA (no signal) and transmit current draw around 125 mA key down. The design incorporates various construction techniques, including knife-cut surface mount boards and through-hole components, often salvaged from junked cordless phones and cellphones. Despite its direct conversion architecture, which offers usable but not superheterodyne-level selectivity, the rig proved effective, achieving a fourth-place finish in a June 2001 Spartan Sprint contest when paired with a 26-foot vertical antenna. The article provides comprehensive circuit details, including an unconventional VFO using a high-speed CMOS inverter chip and a balanced mixer utilizing a 74HC4053.