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An home made HF mobile multiband antenna inspired by the KM4IE HF 20 dollars antenna or the Texas Bugcatcher can work 75 to 15 meters band with an acceptable SWR.

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.

The **Solarcon A99** vertical antenna, a half-wave over a quarter-wave variable mutual inductance design, primarily serves the 11-meter CB band but also finds use on 10 and 12 meters for amateur radio operators. Its simple construction, consisting of three fiberglass sections and a 16 AWG radiating element, makes it an accessible option for new operators or those seeking an easy-to-install base station antenna without complex mounting requirements. Despite claims of 9.9 dBi gain being widely considered exaggerated, and a manufacturer rating of 2000 watts power handling often viewed with skepticism (with 300 watts suggested as a practical limit), the A99 maintains popularity due to its low cost and ease of deployment. It typically tunes to a 1.2-1.3 SWR out of the box, requiring minimal adjustment via its two tuning rings. Its high angle of radiation allows for effective local communication even when mounted at low heights, such as 8-10 feet off the ground. However, the A99 is known for significant RF bleed-over issues, particularly when operated with higher power or mounted close to residential electronics. While its internal design is often described as cheap, the antenna exhibits remarkable durability, frequently lasting a decade or more in various weather conditions. Its affordability and straightforward setup continue to make it a go-to choice for many radio enthusiasts.

This wire antenna for 40 and 20 meter band feature a good SWR. Horizontal side of the antenna is placed at two meters above the ground. Impedance of the antenna are depending by the height of the base from the ground and conditions of the ground

The article, "Using 75 Ohm CATV Coaxial Cable," details methods for employing readily available 75-ohm CATV hardline in standard 50-ohm amateur radio setups. It addresses the inherent impedance mismatch and practical considerations, such as connector compatibility, for hams seeking cost-effective, low-loss feedline solutions. The resource specifically contrasts common 50-ohm cables like RG-8, RG213, and _LMR-400_ with 75-ohm hardline, highlighting the latter's lower loss characteristics, particularly at VHF and UHF frequencies. It explores two primary approaches to manage the impedance difference: direct connection with an acceptable SWR compromise and precise impedance transformation. The direct connection method acknowledges that a perfect 1:1 SWR is not always critical, especially when using low-loss coax. For impedance transformation, the article explains the use of half-wavelength sections of coax to reflect the antenna's 50-ohm impedance back to the transmitter, noting its single-frequency effectiveness. It also briefly mentions transformer designs using toroid cores and a technique involving two 1/12 wavelength sections of feedline for broader bandwidth. The content further clarifies the concept of _velocity factor_ for calculating electrical versus physical cable lengths, providing a generic formula for precise length determination. It notes that while half-wave matching is practical for 10 meters and above, it can result in excessively long runs for lower bands like 160 meters, potentially adding **250 feet** of cable. The article also mentions achieving a usable bandwidth of 28.000 MHz up to at least **28.8 MHz** on 10 meters with specific transformation techniques.

A moxon antenna for the 50 MHz build with 19 feet of 14 AWG copper wire, and based on a set of PVC pipes. This is an easy to build project that will give you an efficient directional antenna on 6 meters band with low SWR on more than 1 MHz bandwidth.

ATV products manufacturer, antennas, ATV transmitters, SWR meters, amplifiers

Have wondered why a Smith chart has such strange grid lines. Believe it or not, there is a logical progression from Speedometers to Smith charts that will make the Smith grid crystal clear.

A guide to measuring SWR with different types of SWR Meters, the single needle and dual needle meters

A fand dipole antenna home made for the 7,14,50 MHz. This article descbribes how to homebrew the antenna, hot to setup and some SWR measurements.

The Buddistick antenna, as demonstrated by KP4MD, effectively handles up to **250 watts** and provides coverage from 40 through 10 meters, with an optional coil extending operation to 80 and 60 meters. KP4MD's video presentation meticulously describes the antenna setup, emphasizing the critical role of the _shunting coil_ for achieving resonance on lower bands like 40 and 80 meters. This practical approach highlights how a compact antenna can deliver solid performance from a constrained location. SWR curve diagrams are included, clearly illustrating the impact of the shunting coil on the antenna's resonating frequency. These visual aids provide concrete evidence of the adjustments needed for optimal operation across different bands, particularly when space is at a premium. KP4MD's insights are particularly valuable for hams operating from apartments or other limited spaces, showcasing real-world results from a balcony installation.

This page describes a comparison study on seven different beam antennas for 40 meters band. Yagi antennas, moxon antennas, mini horse all antennas are described with schema diagram , azimuth plot and SWR F/B Gain diagram

Have you been looking for an easy way to measure power or SWR at 1296 MHz? One thing is certain, it is not easy - simply because the normal range of SWR meters that most of us have is not up to 1300 MHz.

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_.

With this antenna the coverage is 80,40,20,15 and 10 meter band without any antenna tuner and the average SWR is below 1.2 on phone bands. The total antenna lenght is about 23 meters , with one 20.4 meters long segment from the 1:49 transformer to the 110uh coil and about 2.2 meters long segment from the coil to the insulator.

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

This article documents the author's journey in building, modifying, and testing a DIY short vertical antenna for 40, 30, and 20 meters, with potential 80m capability. Initially inspired by Parks On The Air (POTA), the author explores pedestrian mobile operation and details various experiments to enhance antenna performance. The piece highlights challenges, SWR tuning, portability, and practical results, emphasizing a balance between efficiency and size. Ultimately, it showcases the adaptability of DIY antennas for portable ham radio applications.

Building an End-Fed Half-Wave (EFHW) antenna from a kit, as detailed by Frank Bontenbal, PA2DKW, with process photos by Bob Inderbitzen, NQ1R, offers a practical approach for hams. This specific kit, a collaboration between ARRL and HF Kits, targets 10, 15, 20, and 40 meters, making it a versatile option for HF operations. Unlike a center-fed dipole, the EFHW is a half-wavelength antenna fed at one end, which simplifies deployment, particularly for portable use. The construction guide meticulously outlines the assembly of the 49:1 impedance matching network, crucial for transforming the antenna's high impedance (around 2,500 Ohms) to a transceiver-friendly 50 Ohms. Steps include preparing the enclosure by drilling holes for the coaxial connector and antenna connections, followed by the precise winding of enameled copper wire onto a toroid to create the transformer. The guide emphasizes careful insulation removal and soldering for reliable connections. Final assembly involves integrating a 100 pF capacitor for higher band compensation, soldering the transformer's primary and secondary sides, and conducting SWR tests with a 2K7 resistor or a half-wavelength wire. The document also provides examples of wire lengths for different bands, such as 16 feet for 10 meters or 66 feet for 40 meters, demonstrating the transformer's adaptability for various half-wavelength configurations.

This utility program shows the impedance and reflection coefficient parameters (SWR, reflection coefficient magnitude Rho, or Return Loss RL in dB) at both ends of a transmission line and the details of power loss in the line. It includes built-in specifications for approximately 100 different line types. You can modify the specs to see how small changes affect the results or to specify custom lines. All program inputs may be changed directly or you can use spin buttons to make the changes.

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.

This article details a ham radio operator’s experience setting up HF antennas in an antenna-restricted community. Initially using an AEA Isoloop magnetic loop for QRP PSK, the author later built an attic antenna system, including dipoles for multiple HF bands and a slinky dipole for 40 meters. The setup allowed for operation on six bands with acceptable VSWR. Despite space constraints and some compromises, performance was effective. The article highlights practical strategies, emphasizing experimentation and antenna modeling for optimizing performance in limited-space environments. A valuable guide for ham radio operators facing similar restrictions.

The article describes a high-gain, compact beam antenna design for the 2-meter band (144-146 MHz). The NSH 4x4 Boomer is a 4-element antenna that is mounted on a 4-foot boom with an 8.2 dB gain, 1.2:1 SWR, and a front-to-back ratio of 18 db. It is designed for mobile operations and little area, making it perfect for field usage such as disaster management. The design employs regularly spaced parts with a straightforward gamma match for tuning, and the construction materials include a square boom and polished aluminum tubes. In local and portable tests, the antenna worked regularly, achieving contact distances of up to 15 kilometers.

This page provides guidance on designing an End-Fed Half-Wave (EFHW) or Random-Length antenna for amateur HF bands, such as 80 or 40 meters. The content explains how to optimize the antenna for multi-band use and match it to a 50-ohm system using an unun. Hams can generate radiation patterns, VSWR charts, and antenna current diagrams for their customized antenna designs. Understanding how antenna dimensions affect performance is essential for successful field operations. The page caters to ham radio operators looking to build efficient and effective HF antennas for their stations.

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.

The article explores the concepts of return loss, VSWR, and S11 within the context of microwave engineering, highlighting the confusion arising from their definitions. It clarifies that these parameters, while seemingly distinct, fundamentally describe the same phenomenon related to wave reflection and transmission in microwave circuits. The discussion emphasizes the historical context and mathematical relationships among these terms, revealing that their interpretation can vary significantly across different engineering disciplines. Ultimately, it advocates for a pragmatic approach to using these parameters based on familiarity rather than strict definitions.

This page provides information on how to design an Off-Center-Fed Dipole (OCFD) antenna, suitable for amateur HF bands like 80 meters or 40 meters. The antenna design allows for VSWR minima on multiple bands, making it a good choice for multi-band use. Learn how to create an OCFD antenna in either flat-top or inverted-Vee form using a single support. The page also offers tools to generate radiation patterns, VSWR charts, and antenna current diagrams for your specific antenna design, helping hams understand performance factors. Ideal for ham radio operators looking to build their own effective antennas.

This report details a modification of a Diamond V2000 antenna, replacing its original two 0.50 m radials with two 1.55 m radials. Initial M5-threaded rods failed to fit; the housing required M6 threads. Custom radials were made using 8 mm OD aluminium tubing and M6-threaded stainless steel ends, secured with nuts machined to 9 mm. SWR issues on 6 m (>2:1) were largely due to a poor counterpoise connection, resolved during reassembly. NanoVNA measurements showed no adverse effects on 2 m or 70 cm. The final setup retains the two 1.55 m radials and original counterpoise. Other operators reported SWR degradation with similar mods—sometimes fixed by adding capacitance—but this was not observed here.

Demonstrates various technical projects and tutorials for amateur radio operators, focusing on digital modes, monitoring, and station setup. It covers topics such as implementing a _WSPR_ station, setting up ADS-B reception, configuring a _DXSpider_ cluster, and utilizing monitoring tools like Prometheus and Grafana. The resource provides practical guides for integrating modern IT solutions with ham radio activities, including Docker and Linux environments for radio applications. This site also features a publicly accessible online logbook, offering detailed statistics on QSOs by band, mode, and geographical zone, with visual mapping of contacts. It includes a comprehensive amateur radio lexicon, explaining hundreds of terms, and provides a real-time display of the F4HXN station's local weather conditions. The resource also aggregates information on upcoming ham radio events and offers a **SWR simulator** for antenna analysis, allowing users to visualize ROS changes based on frequency and antenna parameters.

The 4m Slim Jim antenna project provides a construction guide for a low-cost, high-performance aerial designed specifically for the 70 MHz FM band. This design achieves a 1:1 SWR across the 4m FM band with straightforward adjustment of the feed point, utilizing RG-58 coax. Its low angle of radiation contributes to effective signal propagation. Construction involves using plastic knitting needles as spreaders and a telescopic fishing pole for support, with components secured using two-part epoxy. Annealed bare single-core copper wire forms the radiating element. The setup process includes raising the antenna at least 3 meters above ground for tuning, adjusting the RG-58 feed point for optimal SWR, and then soldering connections. Waterproofing is achieved with yacht varnish. The design emphasizes low wind resistance for durability, making it suitable for exposed outdoor installations. A PDF construction diagram is available to supplement the written instructions.