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MFJ manufacturer of ham radio antenna products, antenna tuners, antenna analyzers, morse code & CW, SWR wattmeters, antenna accessories , power supplies, audio filters, TVI filters, baluns, coax switches and more

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.

NGC is now distributor for COMET and MALDOL brand antenna products designed, manufactured in Japan. Distributor of DAIWA brand RF SWR/power meters and switching power supplies, antennas, test equipment, antenna analyzers and more

A small and inexpensive measurement device designed to determine antenna performance across the amateur bands through use of automatically collected SWR readings

A Portable Low Frequency Antenna Analyzer, For those of us who like to play with antennas on the ham bands, one of the handiest tools to have around the shack is an "antenna analyzer". These gadgets combine a signal generator and standing-wave ratio (SWR) sensor in a small battery-powered unit.

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.

AEA Wireless Director Software Series turns PC's (running Windows 95/98/2000/ME or NT) into powerful tools that expand the use and power of SWR, Return Loss and Complex Impedance Analyzers.

Various publications through the years have shown how the SWR measured on a shorted (or open) feed line can be used to calculate feed line attenuation

The ZS6BKW antenna, a popular multiband wire antenna, offers improved band matching compared to the traditional G5RV. This construction guide details the process, beginning with specific dimensions: 13.11 meters (43 feet) for the 450-ohm ladder line and initial dipole arm lengths of approximately 14.8 meters each. It emphasizes the critical role of an _antenna analyzer_ for accurate tuning, particularly for determining the velocity factor of the ladder line and achieving a 1:1 impedance match. The article outlines the materials required, including a 1:1 current balun, 450-ohm window line, wire for the dipole arms, and a 50-ohm non-inductive resistor for testing. It provides a step-by-step procedure for cutting the ladder line to its electrical half-wavelength, explaining how to calculate the velocity factor using measured and free-space frequencies. For instance, a measured 50-ohm impedance at 12.54 MHz with a calculated free-space half-wavelength frequency of 11.44 MHz yields a velocity factor of 0.91. Final adjustments involve hoisting the antenna to its operational height and fine-tuning the dipole arm lengths to achieve optimal SWR, specifically targeting 14.200 MHz. The _ZS6BKW_ design is noted for its performance on 80m, 40m, 20m, 10m, and 6m, though it is not optimized for 15m operation. The author, _VK4MDX_, shares practical tips for durable construction using stainless steel wire and cable clamps.

This document details the design and construction of a Vinecom 6N4 dual-band Yagi antenna for the 50MHz (6-meter) and 70MHz (4-meter) amateur radio bands. The antenna features 9 total elements (4 elements for 50MHz, 5 elements for 70MHz) on a 4.236-meter aluminum boom. Computer simulations using MMANA software predict 7.21 dBd gain on both bands with front-to-back ratios of 16.01dB (6m) and 15.37dB (4m). The design uses 12.7mm diameter elements mounted on a 32mm square boom, weighing 5.7kg total. Practical measurements with an MFJ-269 analyzer confirmed good SWR performance across both bands after element length adjustments.

A 50-ohm 10W resistor forms the core of this portable QRP antenna, designed by _K0EMT_ for convenient operation on 160m and 80m. The construction involves soldering the resistor to a BNC connector, with one lead to ground and the other to the center conductor, then insulating the assembly. This minimalist design aims to provide a highly portable solution for low-band QRP operations, acknowledging the inherent trade-offs between antenna size and efficiency. Testing with an antenna analyzer revealed low SWR on both 160m and 80m, with a Yaesu FT-817 confirming good matching. While 40m and 30m showed higher SWR, the primary focus remains on the lower bands. The author successfully tested the antenna with **2.5W CW** output, demonstrating its practical application for QRP field operations where ease of deployment is paramount, even if it means sacrificing some **gain** compared to full-sized antennas.

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.

Optimizing the ZS6BKW antenna for full HF band coverage often requires specific modifications beyond its standard configuration. This resource details several enhancements, beginning with a simple series capacitor to improve 80m SWR, a technique W5DXP found effective for permanent installation due to its minimal impact on higher bands. Further improvements include a 10-inch parallel open stub for 10m resonance, shifting the frequency to 28.4 MHz with an SWR of approximately 1.8:1, a practical solution for Technician class operators. The document then explores a switchable matching section, adding or subtracting one foot of ladder line at the 1:1 choke-balun, which significantly impacts higher frequency bands and eliminates the need for a tuner on 17m. W5DXP's _AIM-4170D_ antenna analyzer measurements confirm these effects. More advanced modifications involve a parallel capacitor for further 80m SWR reduction, requiring remote switching for multi-band operation, and relay-switched parallel capacitors at specific points on the 450-ohm matching section to achieve low SWR on 60m, 30m, and 15m. These detailed steps, including _Smith chart_ analyses for the challenging bands, aim to transform the ZS6BKW into a truly all-HF-band antenna, reflecting W5DXP's practical experience in antenna tuning.

The ZS6BKW multiband antenna, an optimized variant of the classic G5RV, features a 102-foot (31.1 m) horizontal span and a 39.1-foot ladder line matching section. This design, derived by G0GSF (formerly ZS6BKW) in the early 1980s using computer programs and _Smith charts_, aims for improved SWR across multiple HF bands compared to its predecessor. Construction details specify Wireman 554 ladder line and #14 AWG THHN copper wire for the radiators, with precise instructions for determining the velocity factor (VF) of the ladder line using an antenna analyzer or dip meter, ensuring accurate physical length for the matching section. The radiator length is electrically 1.35 wavelengths for the 20-meter band, requiring careful trimming during tuning. Field measurements with an _AIM-4170C_ analyzer by KI4PMI and NC4FB demonstrated good SWR curves and bandwidth on 6, 10, 12, 17, 20, and 40 meters. The antenna was deemed unusable on 15 and 30 meters due to very high SWR, but an LDG AT-100PRO autotuner successfully brought 6 and 80 meters into tune. Contacts were made on 80, 40, 20, and 17 meters, including a **17-meter** contact to Spain. EZNEC models for 80-6 meters are provided, along with an AutoEZ model by AC6LA, which predicted good SWR for 80-10 meters. W5DXP's modifications for an all-band HF ZS6BKW are also referenced.

Demonstrates the construction and implementation of a **two-element phased vertical array** for 40 meters, utilizing _Christman phasing_ techniques. The author, W4NFR, details the process from building individual 1/4-wave aluminum verticals to integrating them into a phased system. The resource covers antenna spacing of 32 feet, elevated radial design, and the critical steps for tuning each vertical to achieve a 1.1:1 SWR before combining them. It also provides insights into calculating precise coax lengths for feedlines and the phasing delay line, emphasizing the use of an MFJ-269 Antenna Analyzer for verification. The finished system exhibits good front-to-back nulls, with an overall SWR ranging from 1.6:1 to 2.2:1, which is managed by an antenna tuner. The project includes detailed photos of the relay box, showing 12 VDC relays capable of handling 5KV, and the control box in the shack for switching between three different antenna pattern configurations. Static bleed-off chokes are incorporated for protection, and the construction emphasizes robust weatherproofing for outdoor elements.

The ZS6BKW multi-band antenna, an optimized variant of the classic G5RV, is presented with detailed construction and tuning instructions. This resource outlines the antenna's design principles, which were developed by _Brian Austin (G0GSF)_ using computer programs and Smith charts to achieve optimal dimensions. It provides specific guidance on calculating and adjusting the lengths of the radiators (L1) and the matching ladder line (L2), emphasizing the critical role of velocity factor (VF) in achieving resonance. The article includes a step-by-step procedure for empirically determining the VF of ladder line using an antenna analyzer, ensuring accurate physical lengths for the matching section. It details the tuning process for the radiators, offering practical tips for incremental adjustments to achieve the best SWR curve. The resource presents SWR measurement results obtained with an _AIM-4170C_ analyzer across multiple bands, alongside predicted SWR graphs from an AutoEZ model. It confirms successful contacts on 80, 40, 20, and 17 meters, including a **17-meter DX contact** to Italy. EZNEC and AutoEZ models for the ZS6BKW antenna, covering 80 through 6 meters, are provided for download, allowing further analysis and customization. The document specifies component details, such as the use of Wireman 554 ladder line and #14 AWG THHN copper wire, and discusses the antenna's performance characteristics, noting high SWR on 15 and 30 meters but successful tuning on 6 and 80 meters with an external tuner.

The NB6Zep Antenna, an electrically shortened 80-meter end-fed wire, addresses space constraints for low-band operation by integrating two loading coils into a 37-foot wire. This design, modeled with _EZNEC_, explores configurations like the quarter-wave sloper and inverted-L, with the latter providing a more vertical radiation pattern and practical backyard deployment. The resource details specific coil construction, recommending 21 uH coils made from _BW coil stock #3026_ or similar, and outlines wire segment lengths for optimal tuning. Performance analysis indicates a radiating efficiency of approximately 27% with good ground conductivity, resulting in a signal typically 3-4 dB down compared to a full-size quarter-wave vertical. The antenna exhibits a narrow bandwidth, around 50 kHz, due to its high Q, necessitating a tuner for broader band operation. Feedpoint impedance is low, with ground resistance playing a critical role in achieving a usable SWR. The article emphasizes the importance of an effective ground rod at the feedpoint for proper operation and tuning, suggesting an antenna analyzer for precise adjustments. It confirms the antenna's suitability for DX, citing successful contacts from Oregon to the East Coast and Hawaii on a 160-meter variant, making it a viable option for urban operators seeking low-angle radiation on 80 meters.

Intermittent fluctuations of SWR readings with MFJ 259B antenna analyzer.

Available worldwide can be used as Arduino Shield or plug it in to you PC , or with a bluetooth adapter connect to Android. With a highly optimized software, KAI200 brings you: a. Antenna analyzer form 1 up to 200 Mhz; b. WSPR transmiter (set up by serial terminal); c. Square Wave Signal generator KAI200 is all you need for your radio whatever it is Yaesu, Icom, Kenwood or Drake and DIY projects.

Enables Android users to operate various _miniVNA_ antenna analyzers via Bluetooth, USB, or Wi-Fi, providing a portable solution for RF measurements. The application supports full control over data acquisition, offering features like custom frequency range selection from 1 KHz to the VNA's full range, and automatic screen adaptation for diverse Android device resolutions. It facilitates intuitive, wizard-based calibration for both reflection and transmission modes, saving calibration data for different VNA types (Standard, Pro, Pro with Extender) to avoid repeated procedures. The software displays critical parameters such as SWR, |Z|, Return Loss, Phase, Rs, and |Xs| on 2-axis graphs or Smith charts, with multi-touch gestures for zoom and frequency shift. It includes a frequency generator mode with independent channels and attenuator control for the miniVNA Pro, along with a sweeper function. The cable data mode automatically calculates phase and loss, measures cable length from less than 1 meter to hundreds of meters, and includes a table of common coax cable velocity factors. An experimental X-tal mode measures resonance frequency, Rs, and Q. Data export options include CSV, ZPLOT, and S1P formats, with CSV import capability. The application also features an SM6ENG Audio mode for SWR tuning without visual reference and provides a miniVNA battery voltage indicator. It supports a wide frequency range, with the miniVNA Extender extending coverage up to **1500 MHz**. The application is compatible with Android version 2.2 and later, tested on devices like the _Galaxy TAB 7.7 P6800_.

Unlock the secrets of RF signal optimization in a presentation covering Balun essentials, diverse types, SWR Analyzer checks, revealing results, Ferrite impedance measurements, and practical applications on feeders and house conductors.

This project details the design and construction of a Spider Quad antenna for HF bands (20m, 17m, 15m, 12m, and 10m). The boomless structure optimizes driver and reflector spacing, enhancing performance. Tuning and impedance matching were refined using antenna analyzers and a 1:2 balun. Final tests confirmed excellent SWR and gain, making this an efficient solution for top performance DXing.