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This device was designed as an SWR and power meter for Radio Amateurs. In addition to SWR, it measures forward and backwards power, therefore can also be used as a wattmeter. With a large measuring range from 1 to 1000 watts, it is suitable for use from QRP to QRO

Operating in antenna-restricted communities presents unique challenges for amateur radio operators, often necessitating creative solutions for antenna deployment. This resource details the design and implementation of stealth antennas within a townhouse community in Exton, PA, where external antennas were strictly forbidden by covenants. The author, WB5NHL, describes his setup, which involved locating the shack in the basement and utilizing an unused space under the roofline of a finished third-floor loft for antenna placement. The content specifically addresses the practicalities of routing coax cables three floors and maximizing antenna performance within limited attic space. It covers solutions for multi-band operation, including dedicated sections for 40-10 meter and 80-meter antennas, along with strategies for mitigating potential interference issues. The approach emphasizes full compliance with community covenants, achieving maximum height-above-ground for horizontal antennas, enabling instant band switching, and efficiently utilizing available attic volume. While acknowledging limitations such as potential interference with high power and fixed antenna patterns, the resource provides a detailed account of a functional compromise for restricted environments. Links to individual pages on _coax cables_, _40-10 meter antennas_, _80-meter antennas_, and _interference issues_ offer deeper dives into each specific aspect of the installation.

Integrating a **160-meter vertical wire antenna** with an existing 80-meter Yagi system presents unique challenges for Top Band operation. This project outlines the author's experiences with seasonal antenna removal and reinstallation, a necessary task for agricultural land use. It details specific issues encountered, such as incorrect coil sizing and relay configuration problems, providing practical insights into common pitfalls. The article describes the iterative tuning process, comparing **NEC model** predictions with actual on-air performance. It emphasizes the importance of precise measurements and adjustments to achieve optimal resonance and impedance matching. The author shares lessons learned from troubleshooting, including the impact of ground system integrity and feedline considerations. Concluding with an antenna checkup, the resource addresses long-term maintenance aspects, including galvanic corrosion prevention and general upkeep for reliable operation.

Steve Nichols, G0KYA, presents a practical examination of ground systems for vertical antennas, drawing heavily on the empirical research of Rudy Severns, N6LF. He explains that a robust radial field is crucial for ground-dependent verticals, effectively replacing the antenna's "missing half" and mitigating severe RF absorption in lossy soil. Nichols clarifies that surface radials do not strictly require a quarter-wavelength; instead, deploying a minimum of 16 to 32 shorter wires often yields superior results compared to fewer, longer ones. The presentation also addresses the common SWR paradox: a poor ground might show a perfect 1:1 match, but adding radials, while potentially raising the SWR to around 1.4:1, significantly improves true radiation efficiency. Nichols defines counterpoises as elevated wire networks that substitute for earth connections, offering solutions for limited-space installations, such as the **Folded Counterpoise (FCP)** for 160 meters. This resource provides actionable engineering data for optimizing vertical antenna performance.

WB8LZR details the construction and initial field results of a multi-band vertical wire antenna, designed to complement his existing horizontal loop for improved DX on 80 meters. The antenna utilizes a 67-foot vertical wire, configured as a quarter-wave radiator on 80m, and employs a 1:1 current balun for RF isolation on 80m, 30m, and 17m. For bands like 40m, 20m, and 10m, where the wire acts as a half-wave or full-wave radiator, an additional impedance transforming _unun_ is integrated to manage the significantly higher feedpoint impedance and voltage. The author notes the vertical's performance as a receiving antenna, observing reduced noise compared to his main horizontal loop, particularly on 80m, and even hearing some long-path signals the loop missed. Initial QRP contacts, including a **1-watt** QSO with a _VP2 station_ on 30m, demonstrate its transmit capability. While the radial system is currently rudimentary, the project outlines practical considerations for multi-band vertical deployment and impedance matching.

A rotatable 40-meter dipole antenna designed and constructed to fit within backyard constraints. The project utilized two fishing poles attached to a fiberglass center pole, resulting in an easy-to-build, lightweight, and cost-effective antenna. Essential materials included fishing rods, a center support pole, mast support, and basic tools. Linear loading was implemented to achieve the necessary length for optimal performance. The antenna, which proved effective during the contest, is ideal for field days and additional contest bands. Assembly and installation were straightforward, showcasing the antenna's practicality and efficiency.

The article details the design and construction of a four-band Moxon beam by a radio amateur. The beam, mounted atop a rooftop tower, aimed for gain over a dipole on 20 meters, cost under $500, and included additional bands. The design features fiberglass spreaders, four bands (20/15/10/6 meters), and a single feedpoint. The construction involved computer modeling, NEC source code, and specific dimensions. The article outlines the assembly, materials, and tuning process, including in-situ adjustments for optimal performance. Despite initial challenges, the beam improved signal strength and facilitated contacts on multiple bands, marking it as the best HF antenna the author has owned.

Presents a detailed construction guide for a 9 dB, 70cm collinear antenna, utilizing readily available _RG58/U_ coaxial cable and PVC pipe for housing. The resource outlines the critical calculations for ½ wavelength sections at 444 MHz, incorporating the coaxial cable's velocity factor of 0.66, which yields a section length of 223 millimeters. It specifies the preparation and soldering of eight such half-wavelength sections, each cut to 231mm to allow for trimming, forming the core of the array. Further instructions detail the integration of a ¼ wave element (169mm #16 solid wire) at the top and a ¼ wave aluminum tube (160mm, 5/16 inch) at the bottom, crimped to the feed point's braid. The guide also addresses RF common mode current suppression by suggesting the use of _FT50-43_ toroids on the feedline. Final assembly steps cover mounting the antenna within ¾" PVC pipe using a wooden dowel, waterproofing connections, and initial SWR checks. The article also discusses scaling the design for different element counts and other VHF/UHF bands.

A vertical antenna project for POTA operations. This shortened antenna is aimed to work from 20 to 40 meter band implementing a loading coil, with an additional wire lenght, determined by on field testing and tuning.

This article addresses the issue of unwanted RF in amateur radio setups and introduces a practical method to measure common-mode currents (CMC) using a homebuilt RF meter. The meter, constructed with readily available materials, measures unwanted RF on the coaxial cable shield by inductively coupling to the shield using a split-bead ferrite. The article provides detailed instructions on building the meter, interpreting measurements, and using ferrite chokes to mitigate RF interference. Emphasis is placed on the importance of verifying CMC levels and installing chokes to improve equipment performance.

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.

The Portable EFHW antenna for the 40, 20, 15, and 10-meter bands utilizes a broadband transformer with a 1:49 ratio, designed on a PCB by either Jan or DL2MAN. The design incorporates an **FT114 core**, offering an alternative to the FT82 core. The antenna requires precisely 20.5 meters of DX Wire Ultralight for optimal performance. Additional components include DX Wires "Dyneema" 1mm rope and 1mm bricklayers string for structural support. The SWR plot indicates performance at two elevation heights: 5.5 meters (blue line) and 4 meters (yellow line), demonstrating optimization for low-elevation portable use without poles. The antenna's components, including spool and rope tensioners, are available for 3D printing, with spool dimensions scaled to 130% for a length of approximately 110mm. The design emphasizes simplicity and portability, suitable for field deployment.

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

The field strength meter (FSM) is a very useful addition to any HAM toolbox. If you are messing around with antennas, or building PA's, or trying to repair some TX gear, the FSM will come to your rescue when there is doubt about the output level.

The PicoFox is a versatile fox transmitter for 2-meter ham radio operators, built around the RP2040 microcontroller. With open-source hardware and software, it can be customized to suit your needs, from APRS to other digital modes. This fully assembled transmitter comes with a rechargeable battery and antenna, ready for use. The design allows for easy addition of features like sensors or interactivity. Modulation is handled in software for smooth FM output, with ample CPU, flash, and GPIO available. Configure your PicoFox by connecting it to a computer via USB and adjusting settings in a text file. Explore the possibilities of this innovative transmitter for your amateur radio projects.

A cost-effective alternative to the Optibeam OB10-3W, a high-performance but expensive tri-band Yagi antenna for the 20, 17, and 15-meter bands. The original Optibeam, featuring three full-size elements on each band, delivers strong forward gain and front-to-back ratio but comes with a high price tag. To address this, a custom design was developed, offering similar performance at a fraction of the cost. Using accessible materials and a simple 1:1 current balun, the homemade version proved highly effective, making it a practical solution.

Explores the addition of a reflector to the traditional Hentenna design for 6m band, providing construction insights, performance comparisons, and modeling data

Single-sideband (SSB) radio enhances spectral efficiency but poses challenges with audio intelligibility, particularly in noisy conditions. A microphone audio compressor addresses these issues by dynamically managing the audio signal’s dynamic range. It amplifies quiet sounds and attenuates loud ones, ensuring consistent audio levels for improved clarity. Benefits include increased intelligibility, higher average power, and reduced spurious emissions. While essential for optimal SSB performance, careful parameter adjustment is crucial to balance natural sound quality and effective communication across various operating modes.

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.

Spectrogram, a PC-based audio frequency spectrum analyzer available from Visualization Software, aids ham radio enthusiasts in aligning receivers like Elecraft K2. Versions are downloadable, with an intuitive interface and customizable parameters. Tutorials by experts like Tom Hammond and John Grebenkemper offer additional guidance.

This article explains the trick of how to shorten and lengthen pairs of radials to make a 2-band ground plane antenna. Included is a "Table of Multi-Band Possibilities" covering the range of 6 to 40 meters.

This page discusses the construction and design of a shortened 2-element Yagi antenna for the 40-meter band, focusing on the driven element. The author shares insights on adding hats to the coil to reduce losses and improve performance. The article also mentions the use of EZNEC modeling software and an AIM4170 analyzer for tuning. Amateur radio operators interested in such antenna design and optimization for the 40-meter band can find useful information and practical tips on this page.

The _MFJ-915_ RF Isolator, rated for 1.8-30 MHz and 1500W PEP, exemplifies the product range available from The Ham Shop. The inventory includes various antenna support ropes, such as 3/16" _Dacron Polyester Rope_ in lengths from 100 to 1500 feet, alongside a selection of cables for _SignaLink USB_ sound card interfaces. Specific SignaLink cables are offered for radios like the Yaesu FT-847 (SLCAB847), Yaesu HTs (SLCABVXY), and the Elecraft K3 (SLCABHTY). Additionally, the shop provides modular jumper cables and modules, including the SLMOD8RY for Kenwood/Alinco 8-pin round mic jacks and the SLMOD8RI for Icom 8-pin round mic jacks. The product line supports diverse station configurations, encompassing antennas, coax, baluns, dummy loads, duplexers, insulators, microphones, power supplies, SWR meters, and watt meters.

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.

After years of reliable performance, a 26-year-old Icom 706MK2G exhibited an unusual deviation during FM transmission, with the actual frequency being 10kHz off from the displayed frequency. Additionally, the power meter showed a sharp dip during transmission. Upon investigation, it was discovered that the FM VCO voltage adjust variable had become dirty and sluggish over time. By adjusting the variable capacitor and cleaning it with switch cleaner, the issue was resolved, restoring stable power output and accurate frequency transmission.

This article describes a DIY RF field strength meter project inspired by VK3YE's "The Squeakie" design. The device, built around a 555 timer IC and a 1N4148 diode, converts RF signal strength into audible tones with proportional pitch. The author enhanced the original design by adding volume control, LED indication, and digital readout capabilities using an Arduino Nano and LCD display. The completed project functions as a versatile RF detection tool, suitable for antenna testing and fox hunting, while offering multiple output methods: audio, visual, and digital measurement display.

The Gemini Amplifier Remote Control software operates on Windows 7 and above, facilitating remote management of the Gemini HF-1K and DX-1200 amplifiers. Users connect via Ethernet, configuring the amplifier's IP address through the front panel. The software allows seamless band and antenna selection, saving settings for each band without requiring transmission. Integration with _OmniRig_ from Afreet Software, Inc. enables automatic band adjustments based on the radio's frequency changes. Users can configure serial or virtual serial connections, with tracking options accessible through the ribbon bar. The software supports speech functionality, enhancing accessibility for operators. Firmware updates, such as version 2.5Ee, introduce features like background datalogging and power output control, uploaded via FTP. Version 1.2.0 allows users to offload internal parameter data for support purposes. The firmware upload process requires the amplifier's IP address and port 21, taking approximately 90 seconds. Users are encouraged to upgrade to the latest firmware for improved performance and remote diagnostics.

An Arduino-based interface provides a remote tuner call command for Icom **IC7700** and **IC7800** transceivers, addressing the lack of a built-in function for external tuners such as the MFJ 998RT. This setup initiates a low-power transmit signal, typically 15 watts, allowing the remote autotuner to perform its matching sequence. The article details the required CI-V line communication and modifications to existing Arduino code, specifically referencing contributions from Jean-Jacques ON7EQ for improved Icom interrogation routines. The system involves a sequence of steps: storing the transceiver's current mode and power, disabling the internal autotuner, activating a control relay to interrupt the amplifier line, switching to RTTY mode at low power, and initiating transmit. The transmit duration is manually controlled by the operator, observing the SWR meter until a low SWR is achieved, then a second button press stops the transmission. A built-in 4-second transmit limit provides a safety measure. After tuning, the routine restores the original mode and power settings, re-enables the internal autotuner, and performs a brief 2-second RTTY transmission for internal tuner adjustment. The circuit diagram includes a Panasonic form 2 relay for amp control and emphasizes critical delays in the Arduino code for stable operation at 9600 baud CI-V communication. Compatibility with logging software like DXLab, N1MM, and N3FJP is noted, with specific interrogation time settings required to avoid conflicts.

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.

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.

The resource provides a technical installation guide for _MeshCom 4.0_, an amateur radio mesh networking project utilizing LoRa hardware modules. It systematically covers the setup process for several supported devices, including the RAK Wireless LoRa WisBlock Core RAK4631, T-Beam T22 V1.1, T-Lora T3 V1.6.1, HELTEC WiFi ESP32 LoRa 32 (V2 and V3), HELTEC E290, ESP32 / E22 modules, and the T-deck from Lilygo. The guide specifies support for the **EU433** frequency band, ensuring amateur radio compatibility, and details the use of an online flash tool for ESP32 modules and an embedded drive for RAK modules. It further describes accessing the MeshCom 4.0 Dashboard and Map functionalities, crucial for network visualization and management. Firmware configuration for ESP32 modules is meticulously outlined, covering essential parameters such as setting callsigns, country codes, and gateway parameters via a serial console like PuTTY. Commands for activating gateway mode, setting internet IP addresses, and configuring WLAN SSID and password for modules with WLAN capability are provided, enabling modules to function as either clients or gateways within the MeshCom network.